Diagnosis and assessment of species boundaries of economically important insects are often problematic because of limited morphological and/or biological characters. DNA data can help to identify and revise species. Nonoverlapping intra- and interspecific sequence divergences are often used as evidence for species. Thus, the establishment of a standardized percent nucleotide divergence to predict species boundaries would aid in cases where species status is suspect. However, given variation in nucleotide mutation rates and species concepts, association between a standard percent sequence divergence and species is questionable. This review surveys the percent DNA sequence difference found between sister-species of economically important insects, to assess whether a standard divergence associates with all taxa. Sixty-two comparisons of intra- and interspecific pairwise DNA differences were made for mitochondrial and nuclear loci spanning families of Isoptera, Phthiraptera, Hemiptera, Coleoptera, Lepidoptera, Diptera, and Hymenoptera. Intra- and interspecific sequence divergences varied widely among insects, 0.04–26.0 and 1.0–30.7%, respectively. The ranges of intra- and interspecific sequence divergences overlapped in 28 of 62 comparisons. This implies that a standardized percent sequence divergence would fail to correctly diagnose species for 45% of the cases. Common occurrence of nonmonophyly among closely related species probably explains this observation. Nonmonophyly and overlap of intra- and interspecific divergences were significantly associated. The reviewed studies suggest that a standard percent sequence divergence does not predict species boundaries among economically important insects. DNA data can help best to predict species boundaries via its inclusion in nonphenetic phylogenetic analysis and subsequent systematic expert scrutiny.

Honey bees, Apis mellifera L., often thought to be extremely susceptible to insecticides in general, exhibit considerable variation in tolerance to pyrethroid insecticides. Although some pyrethroids, such as cyfluthrin and lambda-cyhalothrin, are highly toxic to honey bees, the toxicity of tau-fluvalinate is low enough to warrant its use to control parasitic mites inside honey bee colonies. Metabolic insecticide resistance in other insects is mediated by three major groups of detoxifying enzymes: the cytochrome P450 monooxygenases (P450s), the carboxylesterases (COEs), and the glutathione S-transferases (GSTs). To test the role of metabolic detoxification in mediating the relatively low toxicity of tau-fluvalinate compared with more toxic pyrethroid insecticides, we examined the effects of piperonyl butoxide (PBO), S,S,S-tributylphosphorotrithioate (DEF), and diethyl maleate (DEM) on the toxicity of these pyrethroids. The toxicity of the three pyrethroids to bees was greatly synergized by the P450 inhibitor PBO and synergized at low levels by the carboxylesterase inhibitor DEF. Little synergism was observed with DEM. These results suggest that metabolic detoxification, especially that mediated by P450s, contributes significantly to honey bee tolerance of pyrethroid insecticides. The potent synergism between tau-fluvalinate and PBO suggests that P450s are especially important in the detoxification of this pyrethroid and explains the ability of honey bees to tolerate its presence.

A mark–release–recapture technique was developed and tested for use in tracking the field movements of adult glassy-winged sharpshooters, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), in various agricultural and urban plantings. Greenhouse experiments in which adult H. coagulata were marked with one of five colored fluorescent dusts (Aurora Pink-A11, Horizon Blue-A19, Blaze Orange-A15N, Saturn Yellow-A17, and Corona Magenta-A21) and released into cages with citrus seedlings showed that their mortality rates during a 30-d period were statistically similar to that of the undusted controls. Adults marked with a sixth dust color (Signal Green-A18N) suffered higher rates of mortality than did the undusted controls and thus were eliminated from further consideration. Adult H. coagulata marked with one of the five accepted colors of fluorescent dust were able to fly beyond 100 m in a field devoid of vegetation within minutes of their release, and the marking did not affect overall flight behavior significantly compared with that of the undusted controls. However, at wind speeds above 5 m/s, percentage recapture was significantly reduced, which indicates that both dusted and undusted adults were unable to orient their flight. In total, 41,124 marked and unmarked adults were released in the three field experiments in southern California (Riverside and Kern counties) during 2000 and 2001 to evaluate flight dispersal and estimate densities of H. coagulata. The mark–release–recapture and feral data obtained during the June, July, and August 2001 studies, when coupled with the Lincoln index, yielded estimates of adult H. coagulata of 1.2 and 2.2 million per ha, respectively, at a San Joaquin Valley (Kern Co.) and a southern California (Riverside Co.) citrus grove. The use of colored dusts to mark H. coagulata proved to be reliable, cost-effective, and time-efficient for mark–release–recapture studies with this insect within a citrus grove, but they are less likely to be useful for studies of adult H. coagulata movements among plantings.

Xylella fastidiosa Wells is a bacterial pathogen that causes a variety of plant diseases, including Pierce’s disease (PD) of grapevine, almond leaf scorch, alfalfa dwarf, citrus variegated chlorosis, and oleander leaf scorch (OLS). Numerous strains of this pathogen have been genetically characterized, and several different strains occur in the United States. The dominant vector in southern California is the glassy-winged sharpshooter, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae). The high mobility of this insect, and its use of large numbers of host plant species, provides this vector with ample exposure to multiple strains of X. fastidiosa during its lifetime. To learn more about the ability of this vector to acquire, retain, and transmit multiple strains of the pathogen, we developed a polymerase chain reaction (PCR)-based method to detect and differentiate strains of X. fastidiosa present in individual glassy-winged sharpshooter adults. Insects were sequentially exposed to plants infected with a PD strain in grapevine and an OLS strain in oleander. After sequential exposure, a few insects tested positive for both strains (7%); however, in most cases individuals tested positive for only one strain (29% PD, 41% OLS). In transmission studies, individual adults transmitted either the PD or OLS strain of the pathogen at a rate (39%) similar to that previously reported after exposure to a single strain, but no single individual transmitted both strains of the pathogen. PD and OLS strains of X. fastidiosa remained detectable in glassy-winged sharpshooter, even when insects were fed on a plant species that was not a host of the strain for 1 wk.

Screening of different adjuvants, namely, suspending agents, phagostimulants, stickers, antimicrobial agents, and UV screens to develop aqueous biopesticidal suspensions of Bacillus thuringiensis (Bt) variety kurstaki HD-1 fermented broths, specifically, nonhydrolyzed sludge, hydrolyzed sludge, starch industry wastewater, and soya (commercial medium), were investigated. The selected suspending agents [20% (wt:vol)] included sorbitol, sodium monophosphate, and sodium metabisulfite with corresponding suspendibility of 74–92, 69–85, and 71–82%, respectively. Molasses [0.2% (wt:vol)] increased adherence by 84–90% for all fermented broths. The optimal phagostimulants [0.5% (wt:vol)], namely, soya and molasses, caused entomotoxicity increase of 3–13 and 7–13%, respectively. Sorbic and propionic acids showed high antimicrobial action [0.5% (wt:vol)], irrespective of fermentation medium. Sodium lignosulfonate, molasses, and Congo red, when used as UV screens [0.2% (wt:vol)], showed percent corresponding entomotoxicity losses of 3–5, 0.5–5 and 2–16, respectively. The Bt formulations, when exposed to UV radiation, showed higher half-lives (with and without UV screens) than the fermented broths or semisynthetic soya medium and commercial Bt formulation. UV screen-amended nonhydrolyzed, hydrolyzed, and starch industry wastewater formulations showed 1.3–1.5-fold higher half-lives than commercial Bt formulation. Thus, the recommended formulation comprises sorbitol, sodium monophosphate, sodium metabisulfite (suspending agents); molasses, soya flour (phagostimulants); molasses and skimmed milk powder (rainfasteners); sorbic and propionic acids (antimicrobial agents) and sodium lignosulfate; and molasses and Congo red (UV screens). These waste-based Bt formulations offer better UV resistance in comparison with commercial formulation.

Biological control using hymenopteran parasitoids presents an attractive alternative to insecticides for reducing infestations and damage from the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), in retail and warehouse environments. We examined the potential for using combinations of the egg parasitoid Trichogramma deion Riley (Hymenoptera: Trichogrammatidae), and the larval parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) for preventing infestations of P. interpunctella in coarse-ground cornmeal as well as the influence of packaging on parasitoid effectiveness. Treatments included one or both parasitoids and either cornmeal infested with P. interpunctella eggs or eggs deposited on the surface of plastic bags containing cornmeal. H. hebetor had a significant impact on the number of live P. interpunctella, suppressing populations by ≈71% in both unbagged and bagged cornmeal. In contrast, T. deion did not suppress P. interpunctella in unbagged cornmeal. However, when released on bagged cornmeal, T. deion significantly increased the level of pest suppression (87%) over bagging alone (15%). When H. hebetor was added to bagged cornmeal, there was a significant reduction of live P. interpunctella compared with the control (70.6%), with a further reduction observed when T. deion was added (96.7%). These findings suggest that, in most situations, a combined release of both T. deion and H. hebetor would have the greatest impact; because even though packaging may protect most of the stored products, there are usually areas in the storage landscape where poor sanitation is present.

Field and laboratory studies were conducted to determine the effect of transgenic Bacillus thuringiensis (Bt) corn, Zea mays L. (YieldGard Rootworm), expressing the Cry3Bb1 protein on aboveground nontarget insect predators (minute pirate bug, ladybird beetles, and carabids). Visual counts of adult and immature Orius insidiosus (Say), Coleomegilla maculata (DeGeer), Hippodamia convergens Gurin-Meneville, and Scymnus spp. occurring in Bt corn and its non-Bt isoline were made at Manhattan, KS, in 2002 and at Manhattan and Scandia, KS, in 2003. No significant differences were found between the Bt corn and non-Bt isoline plots in the abundance (number per plant) of O. insidiosus, C. maculata, H. convergens, and Scymnus spp. Field predation on Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) egg masses was also observed during the silking stage of corn at Manhattan and Scandia in 2003. No significant differences were observed among treatments in predation rate for predators with chewing versus sucking mouthparts. Two laboratory studies determined the effect of Cry3Bb1 protein expressed in Bt corn pollen on C. maculata and carabids. The larvae of C. maculata were reared on Bt pollen, non-Bt pollen, or greenbugs, Schizaphis graminum (Rondani). The duration of larval and pupal stages, developmental time from egg hatch to adult emergence, percentage of survival, and elytra length were compared among treatments. There were no significant differences in developmental time of larvae fed pollen or greenbugs during their first two instars. However, significantly prolonged development of the third (1 d) and fourth instars (2 d) was observed for larvae fed greenbugs only. Total time for larval development was significantly longer for larvae that fed on greenbugs versus larvae fed on pollen. No significant differences were observed among treatments in the percentage of larvae that pupated or pupal stage duration. Larvae that fed on greenbugs had higher pupal and adult weights compared with pollen-fed larvae. However, pupal and adult weights did not vary between the Bt and non-Bt pollen treatments. No significant differences occurred in longevity and elytra length of beetles among all treatments. Two carabid species, Harpalus caliginosus F. and Harpalus pensylvanicus DeGeer, were reared on moistened dog food sprinkled with Bt or non-Bt corn pollen. No significant differences in mortality of H. caliginosus and H. pensylvanicus were detected among any of the treatments. There was no significant effect of Bt pollen on fecundity and egg viability of H. caliginosus. Our studies showed that YieldGard Rootworm had no effect on the selected coleopteran predators; therefore, this Bt corn hybrid could be used in an integrated pest management system.

The susceptibility of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) to selected strains of the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin was evaluated through bioassays with direct immersion or foliar exposure under laboratory conditions. Results showed that A. planipennis adults were susceptible to B. bassiana and M. anisoplae. Significant time–mortality response was found for each isolates. Isolate B. bassiana GHA killed A. planipennis adults at a faster rate compared with other isolates tested, with the lowest average time-to-death values. The LC₅₀ values estimated under direct immersion method ranged from 1.7 × 10⁵ to 1.9 × 10⁷, 3.5 × 10⁴ to 5.3 × 10⁵, and 4.1 × 10³ to 2.9 × 10⁵ conidia/ml for B. basissiana and from 3.2 × 10⁶ to 1.1 × 10⁷, 4.5 × 10³ to 4.5 × 10⁵, and 1.4 × 10² to 1.2 × 10⁵ conidia/ml for M. anisopliae at 4, 5, and 6 d after treatment, respectively. By days 5 and 6, B. bassiana GHA outperformed all other isolates tested except ARSEF 7234, followed by ARSEF 7152, 6393, and 7180. Significant concentration–mortality response was also observed for two B. bassiana GHA formulations, BotaniGard ES and Mycotrol O, and M. anisopliae F52 when insects were treated through foliar exposure. The LC₅₀ values ranged from 114.5 to 309.6, 18.4 to 797.3, and 345.3 to 362.0 conidia/cm² for BotaniGard, Mycotrol, and M. anisopliae F52, respectively. Based on the results of these bioassays, the efficacy of both B. bassiana GHA formulations and M. anisopliae F52 were similar against adult A. planipennis. The potential use of entomopathogenic fungi for management of A. planipennis in North America is discussed.

To assess biological control as a management tool for the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), the efficacy of Aphidius colemani Viereck (Hymenoptera: Braconidae) for suppression of A. gossypii in greenhouse-grown chrysanthemums, Dendranthema grandiflora (Tzvelev), was compared with a pesticide standard, imidacloprid (Marathon 1% G) and an untreated check. No significant differences were found between aphid populations in the two treatments. A. colemani and imidacloprid kept aphid numbers very low, with the correspondent aphid populations exhibiting very low intrinsic rates of increase (r_m = −0.0369 and r_m = 0.0151, respectively), in contrast to the exponential growth of aphid populations (r_m = 0.1085) observed on the untreated plants. Parasitism levels in A. colemani plots ranged from 48.93 to 83.38%. Esthetic damage parameters, including exuviae, honeydew, and sooty mold on leaves, were significantly different between treatments and untreated control, and damage levels were minimal with the insecticide treatment and natural enemy releases. The cost of A. colemani releases was 4.7 times greater than the cost of the imidacloprid treatment.

In laboratory bioassays, Steinernema riobrave Cabanillas, Poinar and Raulston (355 strain), Steinernema carpocapsae (Weiser) (Mexican 33 strain), Steinernema feltiae (Filipjev) (UK76 strain), and Heterorhabditis bacteriophora Poinar (HP88 strain) were all capable of infecting and killing three termite species, Heterotermes aureus (Snyder), Gnathamitermes perplexus (Banks), and Reticulitermes flavipes (Kollar) in laboratory sand assays. S. riobrave and S. feltiae caused low levels of Reticulitermes virginicus (Banks) mortality under the same conditions. At 22°C, significant mortality (≥80%) of worker H. aureus and G. perplexus was caused by S. riobrave, in sand assays, indicating the need for further study. Because of the short assay time (3 d maximum), reproduction of the nematodes in the target host species was not recorded. All nematode species were observed to develop to fourth-stage juveniles, preadult stages, or adults in all termite species with the exception of R. virginicus. Only S. riobrave developed in R. virginicus. Nematode concentration and incubation time had significant effects on the mortality of worker H. aureus. S. riobrave consistently generated the highest infection levels and mortality of H. aureus in sand assays.

Commercial formulations and unformulated conidia of Beauveria bassiana strain GHA were applied to field-grown plants and artificially infested with Trichoplusia ni (Hübner) larvae to compare the relative insecticidal activity resulting from direct spray contact with insecticidal activity due to contact with dry spray residue. In general, applications to cabbage, Brassica oleracea L., resulted in nearly equal mortalities when comparing insects exposed to direct spray contact with those exposed by spray residue, suggesting a potential benefit by improving formulations to extend residual activity. For applications to beans, Phaseolus vulgaris L., direct spray contact provided significant insect mortality, but mortality due to residual contact was generally not different than the untreated control. In contrast to the differences observed for larvae exposed in the field, larvae exposed in laboratory bioassays to leaf disks collected from the same treated cabbage and bean plants (residual contact exposure) resulted in nearly identical mortalities. Field applications of Beauveria showed rapid loss of activity, expressed as a loss of conidia viability and loss of insecticidal activity during the first 8 h after application. Evidence of significant mortality by residual contact and the rapid loss of insecticidal activity with field exposure support additional research to improve formulations to extend the residual activity of fungal biopesticides.

Agrotis ipsilon multiple nucleopolyhedrovirus (family Baculoviridae, genus Nucleopolyhedrovirus, AgipMNPV), a naturally occurring baculovirus, was found infecting black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), on central Kentucky golf courses. Laboratory, greenhouse, and field studies investigated the potential of AgipMNPV for managing black cutworms in turfgrass. The virus was highly active against first instars (LC₅₀ = 73 occlusion bodies [OBs] per μl with 2-μl dose; 95% confidence intervals, 55–98). First instars that ingested a high lethal dose stopped feeding and died in 3–6 d as early second instars, whereas lethally infected fourth instars continued to feed and grow for 4–9 d until death. Sublethal doses consumed by third or fifth instars had little or no effect on subsequent developmental rate or pupal weight. Horizontal transmission of AgipMNPV in turfgrass plots was shown. Sprayed suspensions of AgipMNPV (5 × 10⁸–6 × 10⁹ OBs/m²) resulted in 75 to >93% lethal infection of third or fourth instars in field plots of fairway-height creeping bentgrass, Agrostis stolonifera (Huds.), and on a golf course putting green collar. Virus spray residues (7 × 10⁹ OBs/m²) allowed to weather on mowed and irrigated creeping bentgrass field plots significantly increased lethal infection of implanted larvae for at least 4 wk. This study, the first to evaluate a virus against a pest in turfgrass, suggests that AgipMNPV has potential as a preventive bioinsecticide targeting early instar black cutworms. Establishing a virus reservoir in the thatch and soil could suppress successive generations of that key pest on golf courses and sport fields.

Coconut scale, Aspidiotus destructor Signoret (Homoptera: Diaspididae), is a quarantine pest of banana (Musa spp.) and many tropical crops. Irradiation was examined as a potential phytosanitary treatment to control coconut scale. Dose–response tests were conducted with second-stage nymphs, adult females without eggs, and adult females with eggs at a series of irradiation doses between 60 and 200 Gy to determine the most tolerant stage. The adult female with eggs was the most tolerant stage. In large-scale validation tests and dose–response tests, a total of 32,716 adult female scales with eggs irradiated with doses between 100 and 150 Gy produced no F₁ adults with eggs. Irradiation treatment with a minimum absorbed dose of 150 Gy should provide quarantine security for coconut scale on exported commodities.

A study of predation choices of Macrolophus caliginosus Wagner (Heteroptera: Miridae) late instars and adults, when offered various developmental stages (eggs and nymphs) of the recently established whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), was made based on two preference indices. In addition, prey choices of late instars when presented with three ratios of Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) and B. tabaci at a similar developmental stage (eggs, young or late instars) were assessed. M. caliginosus preferred older nymphs of B. tabaci than any other stage. It also chose T. vaporariorum over B. tabaci, unless the latter consisted of >75% of the available prey. These results suggested that M. caliginosus might interfere with parasitoids such as Encarsia, Eretmocerus, or Amitus spp. because all three species emerge from the host pupal case. Furthermore, in mixed infestations, M. caliginosus preference for T. vaporariorum might either negatively affect the control of B. tabaci, or, contrarily, enhance the predator population, before a B. tabaci outbreak occurs in the greenhouse.

Field experiments in the subtropical Lower Rio Grande Valley of Texas were conducted to determine the extent of adult boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), dispersal from cotton, Gossypium hirsutum L., fields during harvest operations and the noncotton-growing (“overwinter”) period between 1 September and 1 February. Using unbaited large capacity boll weevil traps placed at intervals extending outward from commercial field edges, boll weevils did not move in substantial numbers during harvest much beyond 30 m, primarily in the direction of prevailing winds. From traps placed in fallow cotton; citrus; lake edge; pasture; treeline; sorghum, Sorghum bicolor (L.) Moench, and sugarcane, Saccharum spp., habitats during the overwinter period, the most boll weevils were collected in the fallow cotton fields and adjacent treelines during the fall. However, the greatest abundances of boll weevils were found in citrus orchards in the spring, before newly planted cotton fields began to square. One of the three lake edges also harbored substantial populations in the spring. Egg development in females was not detected between November and April, but in cotton fields most females were gravid between May and August when cotton fruiting bodies were available. Mated females, as determined by discoloration of the spermatheca, made up 80–100% of the female population during November and December but declined to ≈50% in February. The lower incidence of mating indicates a reduction in physical activity, regardless of overwinter habitat, until percentages increased in March and April after cotton fields had been planted and squares were forming.

Attraction and feeding responses of oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), were determined for different protein baits. In separate choice attraction assays for each species, significantly more flies arrived at stations with bait than water, but no differences existed among baits of GF-120 Fruit Fly Bait, GF-120 NF Naturalyte Fruit Fly Bait, Provesta 621 autolyzed yeast extract, and Mazoferm E802. In comparison with B. dorsalis, B. cucurbitae had 2.8 times more responders and a 4.8 times better discrimination between baits and water. In a second attraction assay with only B. dorsalis, volume of bait was negatively correlated to numbers of flies alighting on the bait. Feeding assays for both species demonstrated that time spent feeding and duration on a leaf were both significantly affected by bait type. B. dorsalis fed the longest on Provesta 621, with significantly less feeding on the other baits, and with all baits resulting in more feeding than water. The longest feeding times for B. cucurbitae resulted with Mazoferm E802 and Provesta 621, and all baits except GF-120 NF resulted in eliciting a significantly longer feeding duration than water. In separate toxicology assays for each species, significantly higher mortality resulted from bait formulations containing spinosad compared with blank baits, but no differences existed between GF-120 and GF-120 NF formulations. The differences are discussed between the two Bactrocera species primarily in regard to bait preference, extent of response, and previous work on laboratory flies.

The leafminer Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) is a worldwide pest of ornamental and vegetable crops. The most promising nonchemical approach for controlling Liriomyza leafminers in greenhouses is regular releases of the parasitoid Diglyphus isaea (Walker) (Hymenoptera: Eulophidae). In the current study, we examine the hypothesis that the use of D. isaea for biological control of leafminers in greenhouse crops may be more practical and efficient when supplemented with additional control strategies, such as the sterile insect technique (SIT). In small cages, our SIT experiments suggest that release of sterile L. trifolii males in three sterile-to-fertile male ratios (3:1, 5:1, and 10:1) can significantly reduce the numbers of the pest offspring. In large cage experiments, when both parasitoids and sterile males were released weekly, the combined methods significantly reduced mine production and the adult leafminer population size. Moreover, a synergistic interaction effect between these two methods was found, and a model based on our observed data predicts that because of this effect, only the use of both methods can eradicate the pest population. Our study indicates that an integrated pest management approach that combines the augmentative release of the parasitoid D. isaea together with sterile leafminer males is more efficient than the use of either method alone. In addition, our results validate previous theoretical models and demonstrate synergistic control with releases of parasitoids and sterile insects.

Recently, the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), has emerged as a major problem on apples (Malus spp.) grown in the mid-Atlantic and midwestern United States, despite its historically important and frequent occurrence as a peach (Prunus spp.) pest. It is possible that host-driven biological phenomena may be contributing to changes in G. molesta population dynamics resulting in outbreaks in apple. Studies were designed to examine the effects of host plants on oviposition behavior, in an effort to clarify the host association status of eastern U.S. populations and also to gain insight into how pest modeling and management efforts may be altered to take into account various host-associated effects. G. molesta adults exhibited ovipositional preference for nonbearing peach trees over nonbearing apple trees in close-range choice tests conducted in the field, regardless of the larval host origin. A significant preference for peach shoots over apple shoots was observed on six of 12 sampling dates with a wild G. molesta population at the interface of adjacent peach and apple blocks. Numbers of eggs found on apple fruit were higher after peach fruit were harvested and apple fruit began to approach maturity (during the flight period for third and fourth brood adults). Possible implications for population modeling and integrated management of G. molesta are discussed.

Treating Mexican grapefruit with gibberellic acid (GA₃) before color break, significantly delayed peel color change and increased peel puncture resistance, but it did not reduce grapefruit susceptibility to Mexican fruit fly, Anastrepha ludens (Loew) attack under natural conditions. Despite GA₃ treatments, larval infestation levels increased with higher fruit fly populations, which also increased as the season progressed. Late in the season, infestation levels were even higher in GA₃-treated fruit compared with untreated fruit, possibly because treated fruit were in better condition at that stage. Egg clutch size was significantly greater in very unripe, hard, GA₃-treated fruit at the beginning of the harvest season and in December, compared with control fruit. Under laboratory conditions, egg injection into different regions of the fruit suggested that A. ludens eggs are intoxicated by peel oil content in the flavedo region. However, A. ludens’ long aculeus allows females to oviposit eggs deeper into the peel (i.e., albedo), avoiding toxic essential oils in the flavedo. This makes A. ludens a particularly difficult species to control compared with other citrus-infesting species such as Anastrepha suspensa (Loew), Anastrepha fraterculus (Wiedemann), and Ceratitis capitata (Wiedemann) (fly species with significantly shorter aculei), which can be effectively managed with GA₃ sprays. We discuss our findings in light of their practical implications and with respect to the oviposition behavior of various fruit flies attacking citrus.

Powders that adhere to insect cuticle can be used as carrier particles for synthetic insecticides, entomopathogens, or pheromones in insect control systems, and insects can be lured into contact with such powder mixtures by using attractants. Secondary transfer of adhesive powders to conspecifics during social interactions has been reported; however, this transfer relies on insects leaving the source of powder and continuing normal behavior when contaminated. We examined the ability of the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae), to fly and mate after being contaminated with one of two adhesive powders: an electrostatic wax powder, Entostat, and a proprietary metallic powder, Entomag. During continuous observations for 1 h in a flight tunnel, male C. capitata made significantly more flights than females. Treating C. capitata with either powder significantly suppressed the flight activity of male C. capitata compared with untreated controls, whereas powder treatment had a negligible effect on female flight activity. Within 1 h, male C. capitata treated with Entomag recovered normal flight activity, but Entostat-treated males were not fully recovered. Virgin male C. capitata treated with either Entostat or Entomag were able to mate with virgin female C. capitata, but the onset of mating was delayed compared with control C. capitata by ≈1 h. Even though the effect of powder uptake on behavior seemed to be temporary, scanning electron micrograph images of treated C. capitata showed that both powders were retained for >24 h on most body parts. The adhesive powders showed potential for use as carrier particles for pesticides, entomopathogens, or pheromones in novel C. capitata control systems.

A recently synthesized kairomone blend, based on the volatiles produced by potato (Solanum spp.) plants, has been demonstrated to be attractive to both adult and larval stages of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). It was subsequently formulated in a viscous inert carrier for field applications and showed potential for aggregating beetles in treated areas of the field. We investigated effects of this kairomone formulation on the potato aphid, Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae). The response of both winged and wingless adults to natural potato foliage and synthetic kairomone was tested in a Y-tube olfactometer. Aphid response to untreated potato foliage, foliage treated with the kairomone blend, and foliage treated with blank inert carrier also was tested in petri dishes. In addition, aphid densities on field plots treated with kairomone and blank inert carrier were compared with the control plots. The untreated potato foliage was found to be attractive to wingless, but not winged, potato aphids. In the olfactometer, the foliage treated with synthetic Colorado potato beetle kairomone was not attractive to either winged or wingless aphids. In petri dishes, aphids avoided leaflets treated with both kairomone formulation and its blank carrier. There was no statistical difference between any treatments compared in the field.

The root aphid Tetraneura nigriabdominalis (Sasaki) (Homoptera: Pemphigidae) is a pest of many Gramineae species; however, little is known about its biology and relationships with host plants. The objectives of this study were to quantify the effects of temperature on development, longevity, fecundity, and population growth of T. nigriabdominalis and to assess the effects of host plant on development of T. nigriabdominalis. The effects of temperature on performance of this root aphid were determined at 10, 15, 20, 25, 30, and 35 ± 1°C on rice roots, Oryza sativa L. Nymphal stages from birth to adult decreased from 46.3 d at 10°C to 8.5 d at 30°C. Aphid survival and development were lowest at 35°C, and no aphid produced progeny at this temperature. Average adult longevity decreased from 23.3 d at 15°C to 8.2 d at temperatures up to 35°C. Average number of nymphs produced per female was highest at 25°C; averaging near 30 nymphs per female, but it dropped to near zero at both 10 and 35°C. The highest intrinsic rate of increase (r_m) was 0.241 at 30°C. Net reproductive rate (R₀) ranged from 29.8 at 25°C to 0.2 at 10°C. The generation time (GT) decreased with increasing temperatures from 60.3 d at 10°C to 13.8 d at 30°C. In addition, root aphids reared at 30°C on three host plants [O. sativa, Zea mays L. and Sorghum bicolor (L.) Moench] revealed that the developmental time of the nymphal stages averaged 6.9 d when reared on O. sativa and 10.7 d when reared on Z. mays. Comparison of the nitrogen content of the three host plants indicated that the root nitrogen content was highest in O. sativa. The effect of nitrogen content on aphid performance, however, is still not clear. Other factors, such as plant secondary chemistry, may play a role in affecting aphid performance.

Changes in fitness parameters as a function of colony size (one versus 10 aphids) were measured in two biotypes (RWA1 and RWA2) of the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), feeding on three cultivars of wheat, Triticum aestivum L., at two temperatures. ‘Trego’ is a cultivar with no specific resistance to D. noxia, whereas, ‘Stanton’ and ‘Halt’ express Dny and Dn4 resistance sources, respectively. Feeding in a group accelerated the development of RWA1 on Trego and Stanton at 20°C, but not at 24°C, whereas grouped RWA2 developed faster than solitary RWA2 on all three cultivars at 24°C, but not at 20°C. Survival (first instar–adult) of RWA2 also was improved by grouping on Stanton and Halt at 24°C, but solitary RWA2 survived better at 20°C on all three cultivars. The reproductive rate of RWA1 was improved by grouping on Trego and Stanton at both temperatures, but only on Halt at 24°C. Lifetime fecundity of RWA1 also was increased by grouping in all cases except for Trego at 20°C. Grouped development increased the reproductive rate of RWA2 on all three cultivars at 24°C, but had no effect at 20°C. Grouped RWA2 developed and reproduced faster than grouped RWA1 on all three cultivars at 24°C. Thus, the fitness of D. noxia was positively correlated with group size during colony establishment, but the effects were sensitive to temperature, being more pronounced at 20°C for RWA1 and at 24°C for RWA2.

Effects of an organophosphorus insecticide, malathion, on survivorship and lipid peroxidation of the greater wax moth, Galleria mellonella (L.), pupae were investigated by rearing the newly hatched larvae on an artificial diet containing 0.01, 0.1, 1, 10, and 100 ppm of the insecticide. As bioindicators of long-term physiological stress responses, the adult emergence rate, longevity, and fecundity associated with lipid peroxidation level and antioxidant enzyme activity in the endoparasitoid Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae) were determined by rearing the parasitoid on a factitious host, G. mellonella pupae treated with malathion. At 100 ppm, malathion significantly decreased pupation rate of G. mellonella larvae and the rate of adult emergence of the parasitoid from these pupae. This concentration resulted in a significant increase in the lipid peroxidation product malondialdehyde (MDA) in both the host and the parasitoid. Malathion at 1 and 10 ppm significantly increased pupation rate and lipid peroxidation level of G. mellonella pupae. The adult emergence rate of P. turionellae was significantly decreased from 63.7 to 20% by these concentrations, whereas MDA content was increased by two- and three-fold, respectively, compared with the control (45.3 ± 3.2 nmol/g protein). The longevity of adults was significantly extended from 52.5 ± 5.7 to 75.7 ± 6.3 d when the parasitoids emerged from host pupae exposed with 0.1 ppm malathion. At low concentrations (0.01 and 0.1 ppm), malathion significantly increased the number of eggs laid per female per day. However, the lowest concentration (0.01 ppm) had no significant effect on hatchability, whereas 0.1 ppm of the insecticide resulted in significant decrease in egg hatch compared with the control. A significant increase in total superoxide dismutase (SOD) activity for low concentrations of malathion (0.01–1 ppm) was found compared with the control. There was a significant positive correlation of SOD activities with adult longevity and fecundity. This study suggested that malathion-induced oxidative stress was causative factor in the deterioration of biological fitness and that increased SOD activities may have resulted in decreased oxidative damage, which retarded the rate of deteriorative physiological changes in P. turionellae in response to sublethal doses of malathion.

Cultivars of glandular-haired alfalfa, Medicago sativa L., such as ‘54H69’, are currently available and marketed as being resistant to potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae). 54H69 and a standard, nonglandular-haired alfalfa ‘Choice’ were evaluated at two locations in Virginia over a 3-yr period. Dry matter yields and concentrations of crude protein and acid detergent fiber were compared at the first, second, and third harvests. Overall, the two cultivars produced similar dry matter yields of comparable forage quality in the absence of insecticides at both locations in each year. Untreated 54H69 did not produce greater dry matter yields than untreated Choice under either light or heavier potato leafhopper pest pressure. Concentrations of crude protein did not vary between the two cultivars at any harvest. Some differences in concentrations of acid detergent fiber were detected between cultivars, but these differences were not consistent among years, harvests, or between locations. Further comparisons between untreated 54H69 and treated Choice were made, but few significant differences were detected in dry matter yields or forage quality. An economic analysis for the study indicated that a grower planting 54H69 would realize less net revenue than a grower planting Choice, largely because of the seed premium for the glandular-haired cultivar and the evident need to treat 54H69 with insecticide for control of alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), and potato leafhopper.

The moth Tecia (Scrobipalpopsis) solanivora Povolny (Lepidoptera: Gelechiidae) is the most important pest of potato, Solanum spp., in Central America and adjacent South American countries. Insecticide treatments are not sufficiently effective; therefore, we investigated the feasibility of pheromone-mediated mating disruption for control of T. solanivora. Pheromone dispensers were formulated with 70 mg of the three sex pheromone compounds (E)-3-dodecenyl acetate, (Z)-3-dodecenyl acetate, and dodecyl acetate, in a ratio of 100:56:100, respectively. Male attraction to these compounds is optimal at a ratio of 100:1:20, thus the mating disruption dispensers contained an off-blend, which attracted only a few males. Nonetheless, one mating disruption dispenser suppressed male attraction to calling females in a flight tunnel and reduced male activation in response to female pheromone. Communication disruption is accordingly due to camouflage of the female signal and possibly due to a reduction of male responsiveness by sensory imbalance. Only a few males were observed in a 3-ha potato field treated with 84 g pheromone/ha, compared with an untreated control field. During 2 mo, male attraction to traps baited with calling females or synthetic pheromone was strongly reduced. This reduction confirms the potential of mating disruption for management of T. solanivora. The efficacy of the pheromone treatment can be further improved by earlier dispenser application, by increased dispenser load, and by treatment of larger fields to reduce immigration of mated females.

In some parts of the boll weevil’s, Anthonomus grandis grandis (Boheman) (Coleoptera: Curculionidae), distribution from the United States to Argentina, insecticides are applied after cut-out (end of square production) when bolls are the predominant stage of fruiting body. This study demonstrates that the standard spray regime in southern Texas, which involves insecticide applications after cut-out, did not result in more bolls than a nonsprayed control. An alternative “proactive” spray regime focusing on protecting large squares before cut-out resulted in 1.9- to 2.5-fold more bolls in the lower half of the canopies than the control. At one of two experimental field locations, the percentage of damaged boll carpels was 3-fold greater in the standard spray regime’s lower canopy than in the proactive spray regime, and the percentage in the control was 1.6-fold greater than in the standard regime. At both experimental field locations, the upper canopy control had 2.1- to 2.3-fold greater percentages of carpel damage than the proactive spray regime. The standard spray regime resulted in 2.3-fold greater percentage of carpel damage than the proactive regime. In the control and the standard spray regime, percentages of upper canopy nondamaged bolls were mostly lower than or not different from percentages of bolls with one, two, three, or all four carpels damaged, but in the proactive regime, percentage of nondamaged bolls in the upper canopy was greater than percentages of bolls with one or more damaged carpels. Reasons for the ineffectiveness of the standard spray regime and the benefits observed in the proactive approach are discussed.

We studied imidacloprid application methods and timing to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in forests. The methods compared were 1) soil injection near the trunk; 2) soil injection dispersed throughout the area under the canopy; 3) soil drench near the base of the trunk; and trunk injection with the 4) Arborjet, 5) Wedgle, and 6) Mauget systems. The applications were made in the fall and the following spring. Adelgid populations on the hemlocks (Tsuga spp.) were assessed in the fall of two successive years after the treatments. Relative to the untreated control trees, all the soil applications resulted in population reductions, but none of the trunk injections resulted in reductions. Fall and spring treatment efficacy did not differ. Reductions by the soil treatments were between 50 and 100% (avg 80%) by the first fall and 83–100% (avg 98.5%) by the second fall. Analysis of imidacloprid residues using enzyme-linked immunosorbent assay found residues in sap, needles, and twigs 1 mo to 3-yr after application. A laboratory dose–response bioassay using excised, adelgid-infested hemlock branches with cut ends immersed in serial dilutions of imidacloprid determined the LC₅₀ value to be 300 ppb, based on an exposure of 20 d. A high degree of suppression of the adelgid on forest trees was associated with residues in hemlock tissue >120 ppb 2 yr after soil treatment. Although precise relationships between residues and efficacy are elusive, it is clear that soil application of imidacloprid resulted in chronic residues of imidacloprid in tissues and suppression of adelgid populations for >2 yr.

The pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), is a serious insect pest infesting open field lettuce plantings in northern Italy. In these cropping systems, it coexists with several other agromyzid species that have negligible economic importance on open field vegetables. The rapid detection of L. huidobrensis is crucial for effective management strategies, but the identification of agromyzids to species can be very difficult at adult as well at immature stages. In this study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism assay is proposed to separate L. huidobrensis from Liriomyza bryoniae (Kaltenbach), Liriomyza trifolii (Burgess), and Chromatomyia horticola (Goureau), which usually occur in the same lettuce plantings. An ≈1,031-bp region of the mitochondrial genome encompassing the 3′ region of cytochrome oxidase I, the whole leucine tRNA, and all of the cytochrome oxidase II was amplified by PCR and digested using the enzymes PvuII and SnaBI separately. Both endonucleases cut the amplicons of L. huidobrensis in two fragments, whereas the original band was not cleaved in the other analyzed species. The presence of Dacnusa spp. DNA does not bias the assay, because the PCR conditions and the primer set here described do not amplify any tract of this endoparasitic wasp genome.

The production of clementine fruit was affected by varying densities of Aphis spiraecola Patch (Hemiptera: Aphididae) maintained on four groups of clementine, Citrus clementina Hort. ex Tan., trees individually isolated in mesh cages. A formula relating the number of aphids per square meter of canopy per group of trees to yield loss in that group of trees was obtained, permitting us to calculate the economic injury levels (EILs) and economic thresholds (ETs) for treatment against A. spiraecola, i.e., EIL, ET, environmental economic injury level (EEIL), and environmental economic threshold (EET). In an example case with current values, EIL = 370, ET = 322, EEIL = 614, and EET = 533 aphids per m² of canopy. Formulae designed for easier use in the field were obtained to express each of these thresholds. The formulae are compared with those obtained for Aphis gossypii Glover in a previous study; the intervention thresholds for A. spiraecola are slightly higher than those found for A. gossypii.

Experiments were conducted to test a mating disruption program for the mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) in California vineyards. The sprayable, microencapsulated formulation of the racemic sex pheromone lavandulyl senecioate was applied with an air-blast sprayer, using three and four applications in 2003 and 2004, respectively. Mating disruption was combined with an application of buprofezin (2004) in June. Compared with a no-pheromone control, there were significantly lower season-long trap catches of adult males, season-long mealybug densities (2003 only), and crop damage in mating disruption plots. The amount of mealybug reduction and mechanisms that resulted in lower crop damage in mating disruption plots is discussed. In samples taken during the growing season (April to September), mealybug density was only 12.0 ± 15.6 and 31.1 ± 11.6% lower in the mating disruption plots than in control plots in 2003 and 2004, respectively. In the mating disruption treatment, mealybug egg production was significantly lower (2003 only), as were the proportion of ovisacs and crawlers produced. There was no treatment impact on percentage of parasitism. Mealybug density influenced treatment impact. In 2004, vines were categorized as having low, medium, or high mealybug densities during a preapplication survey. After treatment application, mealybug density was reduced by 86.3 ± 6.3% on vines in the low mealybug density category, but it was unchanged on vines in the high density category. Another factor that reduced treatment impact was the relatively short effective lifetime of the sprayable formulation.

Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite 50 WP (bifenazate), for control of twospotted spider mite, Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). In greenhouse tests, three treatments consisting of releases of P. persimilis, N. californicus, and an untreated control were evaluated. Both species of predatory mites significantly reduced twospotted spider mite numbers below those found in the control during the first 3 wk of evaluation. However, during week 4, twospotted spider mite numbers on the plants treated with P. persimilis increased and did not differ significantly from the control. Field studies used releases of P. persimilis and N. californicus, applications of Acramite, and untreated control plots. Both N. californicus and P. persimilis significantly reduced populations of twospotted spider mite below numbers recorded in the control plots. During the 2003–2004 field season P. persimilis took longer than N. californicus to bring the twospotted spider mite population under control (<10 mites per leaflet). Acramite was effective in reducing twospotted spider mite populations below 10 mites per leaflet during the 2003–2004 field season but not during the 2004–2005 field season, possibly because of a late application. These findings indicate that N. californicus releases and properly timed Acramite applications are promising options for twospotted spider mite control in strawberries for growers in north Florida and other areas of the southeast.

Studies were designed to examine the effects of host plants on oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), survival. G. molesta larval survival in the orchard was comparable between apple (Malus spp.) and peach (Prunus spp.) shoots, indicating that both host species can harbor large larval populations during the early season. G. molesta larvae used multiple shoots for feeding and development on peaches but usually only damaged single shoots in apple. Survival differences were present between peach and apple fruit, but this survival was affected by fruit maturity level. Generally, larval survival higher was in ripening peach fruit than in green, immature apple fruit. Larval survival varied among several apple cultivars, indicating that cultivar-level variability needs to be considered. These host-associated effects may impact efforts to predictively model G. molesta populations in commercial orchards where multiple host plant species, or different cultivars of the same species are often grown in proximity. Thus, host-associated dynamics should be included into future population models that underlie management programs.

The midge Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae) was first confirmed in North America in Ontario, Canada, in 2000. The insect is now distributed throughout many counties in the provinces of Ontario and Québec. Nearly 1,200 farms in the northeastern United States that grow cruciferous vegetables are at risk for C. nasturtii infestation if this insect were to spread to that region. Over a period of 3 yr (2002–2004), ≈3,000 ha of crops on 94 farms in western New York State was scouted for C. nasturtii, but none were found. In 2004, 42 experimental pheromone traps were placed in fields of cruciferous vegetables in eight counties. C. nasturtii males were captured at low levels (1–50 per trap/8 wk) on four farms in Niagara County, but not at any other site. C. nasturtii larvae were found in plant tissue at one of the four farms. Insect specimens were identified by morphological methods, molecular methods, or both. This is the first confirmation of C. nasturtii in the United States, which we believe was made possible by the combined use of pheromone traps, morphological characters of trapped adults, and molecular methods. The early detection in New York presents an opportunity to implement measures to limit the spread and establishment of C. nasturtii across the state and into other regions of the United States.

GF-120 is a baited formulation of the insecticide spinosad containing 1% ammonium acetate, developed for control of economically important fruit flies. The response of feral cherry fruit flies, Rhagoletis cingulata Loew, to GF-120 augmented with 0, 5, or 10% ammonium acetate was evaluated under orchard conditions. Significantly more flies were observed within 30 cm of bait droplets with 10% ammonium acetate added compared with standard bait or to a water control. These fly visits to GF-120 enhanced with 10 or 5% ammonium acetate lasted an average of 263.2 ± 85.2 and 337.6 ± 72.6 s, respectively, compared with 50.3 ± 36.4 s for standard GF-120. Droplets containing additional ammonium acetate also were contacted by more flies, and more flies fed upon these droplets than on GF-120 or the water control. Furthermore, the duration of feeding on GF-120 bait enhanced with either level of additional ammonium acetate was significantly greater compared with standard GF-120 or water. Feeding events lasted between 61.5 ± 30.7 and 73.4 ± 21.0 s on enhanced GF-120 compared with 6.8 ± 5.7 s on standard GF-120. Collectively, these results indicate that the interaction of feral R. cingulata with GF-120 droplets and the toxicant spinosad can be increased by addition of ammonium acetate.

Development of Epipyas postvittna (Walker) (Lepidoptera: Tortricidae), on leaves and fruit of ‘Valencia’, ‘Washington navel’, and ‘Navelina’ orange trees was studied under constant and fluctuating temperatures. E. postvittna was able to complete its life cycle feeding exclusively on leaves or fruit of orange trees. However, larval survival rate was very low (<20%) on orange tissues compared with that on noncitrus hosts. Among the four types of orange tissues, young orange leaves and fruit afforded larvae higher survival rates than mature orange leaves and fruit. Fruit (young or mature) produced heavier pupae than leaves (young or mature). Larvae developed more slowly on mature orange fruit than on other orange materials and more slowly on orange leaves than on leaves of most noncitrus hosts. Degree-day accumulations based on the fastest developmental rates obtained in this study suggested that E. postvittna is capable of completing 4.4–4.7 generations per year in orange orchards in the Riverina region of New South Wales, Australia. Implications of the results in the management of the insect in citrus are discussed.

Field experiments quantified the effect of synthetic pheromone release-site density and distribution on 1) orientational disruption of male codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), to pheromone-baited traps; and 2) fruit injury. A clustering test varied pheromone release-site density from 0 to 1,000 Isomate-C Plus dispensers per ha while maintaining the total number of dispensers at 1,000. Percentage of orientational disruption of pheromone-baited traps increased significantly as a function of increasing density of release sites. Fruit injury decreased as the density of release sites increased and was lowest in plots treated with Isomate-C Plus dispensers distributed as 1,000 point sources per ha. We also manipulated point source density of 0.1-ml paraffin-wax drops containing 5% codlemone [(E,E)-8,10-dodecadien-1-ol], and thus the total amount of pheromone deployed per hectare. The percentage of disruption of traps baited with either 1.0- or 0.1-mg codlemone lures increased with increasing density of wax drops deployed. Both trapping and field observations confirmed that wax drops were attractive to male codling moths, suggesting that disruption was mediated by competitive attraction. Development of dispensers that can be mechanically applied at high densities has potential to improve the efficacy and economics of codling moth disruption at high population densities.

The three key lepidopteran pests of cole, Brassica oleracea L., crops in North America are diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae); cabbage looper; Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae); and imported cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae). Two species-specific pheromone-based experimental attracticide formulations were evaluated against these pests: LastCall DBM for P. xylostella and LastCall CL for T. ni. No LastCall formulation was available against P. rapae. Laboratory toxicity experiments confirmed the effectiveness of each LastCall formulations in killing conspecific males that made contact. In replicated small plots of cabbage and collards in central Alabama, over four growing seasons (fall 2003, spring 2004, fall 2004, and spring 2005), an attracticide treatment receiving the two LastCall formulations, each applied multiple times at the rate of 1,600 droplets per acre, was compared against Bacillus thuringiensis subspecies kursatki (Bt) spray at action threshold and a negative untreated control. Efficacy was measured by comparing among the three treatments male capture in pheromone-baited traps, larval counts in plots, and crop damage rating at harvest. LastCall provided significant reductions in crop damage comparable to Bt in three of the four seasons. Efficacy of LastCall was dependent upon lepidopteran population densities, which fluctuated from season to season. In general, reduction in crop damage was achieved with LastCall at low-to-moderate population densities of the three species, such as typically occurs in the fall in central Alabama, but not in the spring when high P. rapae population pressure typically occurs in central Alabama. Significant reductions in pheromone trap captures did not occur in LastCall plots, suggesting that elimination of males by the toxicant (permethrin), rather than interruption of sexual communication, was the main mechanism of effect.

Control information for the desert subterranean termite Heterotermes aureus (Snyder) (Isoptera: Rhinotermitidae) is limited, despite being one of three major termite pests in the United States. Annual control information comes from field evaluations by the USDA–Forest Service. This partial assessment of termiticide efficacy is likely deficient without concurrent residual analysis and laboratory bioassays of termiticides. In this study, six termiticides were evaluated using exposed and covered field plots in Tucson, AZ, over a 5-yr period for persistence and efficacy by using both residue analysis and laboratory bioassays. All the termiticides degraded significantly during the study. Termiticide degradation seemed to be consistently slower in covered plots than in exposed plots, although this trend was not statistically supported. A comparison of yearly degradation rates showed the three classes of termiticides degraded at different rates. Chlorpyrifos, the organophosphate, degraded quickest at a rate of 68.9% for each doubling of time, whereas chloronicotinyls and pyrethroids degraded at much slower rates (50.4 and 48.4% for each doubling of time, respectively). Bioassays showed termites tunneled 1.26 ± 0.61 cm deeper in uncovered plots than in those that were covered. Mortality rates in bioassays from covered treatments were 16.13 ± 9.87% higher than in uncovered treatments. Our study demonstrated that the termiticides evaluated could remain effective against H. aureus for at least 4 yr after application, particularly under covered conditions. Additionally, it is anticipated that retreatments may be necessary before the 5-yr warranty expires when using final grade applications to stem walls in warmer parts of Arizona.

We investigated the efficacy of various chemical injections against Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) in hardwood shipping pallets. We had three principle interests: efficacy in whole structures, relative efficacy of the active ingredients, and whether acoustic evidence augmented treatment site selection. Infested pallets were delineated into boards with four monitoring sites each. Six chemical treatments were compared: chlorpyrifos aerosol, aqueous disodium octaborate tetrahydrate (DOT), resmethrin aerosol, distilled water (control), and two treatments of spinosad SC (one treatment applied based upon visual and the other treatment upon acoustic [AE] evidence). Individual boards were split apart; efficacy was determined by percentage mortality and pre- and posttreatment AE counts. Injections were constrained to a single point per board with the greatest level of termite activity. In whole pallets, mean percentage mortality ranged from 53.3 to 58.7% for the visual and AE spinosad treatments, respectively, whereas water averaged 6.8%. Remaining treatment mortalities were 33.2, 30.4, and 18.1% for chlorpyrifos, DOT, and resmethrin, respectively. Analysis of whole-pallet data indicated that none of the insecticides produced commercially acceptable mortality; localized injections of insecticides were not comparable with whole-structure treatments. We delineated independent groups of board sections (sectional aggregates; SA) that were connected by galleries. When treated SA were analyzed, spinosad and DOT treatments were significantly different from controls, whereas remaining treatments were not different from controls or spinosad and DOT. AE readings and visual termite evidence were compared with presence or absence of termites in SA, and it was determined that both AE and visual evidence were effective predictors of termite presence.

Bistrifluron, a benzoylphenylurea compound, was evaluated with regard to its efficacy against workers of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) by using three laboratory tests. In the no-choice feeding test, the mortality of bistrifluron-treated worker termites was significantly higher than that of termites exposed to the same concentrations of hexaflumuron (e.g., 6 wk at 500 ppm, 4 wk at 5,000 ppm, and 2 wk at 50,000 ppm) and untreated controls. Bistrifluron showed higher dose dependence and a faster speed of action than hexaflumuron. Both bistrifluron and hexaflumuron had feeding-deterrent effects at 5,000 ppm in the two-choice feeding test, although the mortality of worker termites exposed to bistrifluron or hexaflumuron at 5,000 ppm was not significantly different from untreated controls. In the allogrooming inhibition test, to examine effects of bistrifluron on allogrooming behavior of termites, termite movement was affected at 1 wk before termites died when exposed to 5,000 ppm bistrifluron. These results indicate bistrifluron is effective as a bait toxicant at 5,000 ppm; however, bistrifluron may cause some feeding repellency at ≥5,000 ppm.

Laboratory bioassays using leaf disks of apple dipped in test solutions of insecticides demonstrated that the apple aphid, Aphis pomi De Geer, and the spirea aphid, Aphis spiraecola Patch, differed significantly in susceptibility to a number of insecticides registered for control of aphids on apple (Malus spp.). Compared with A. pomi, A. spiraecola was approximately four- and three-fold less susceptible to pirimicarb and lambda-cyhalothrin, respectively, whereas there was little difference in response to dimethoate. Pymetrozine is thought to act on aphids primarily as a feeding inhibitor. Exposure of aphids to this material generated data that fit the probit model for only half the tested clones. However, the LC₅₀ value for one clone of A. spiraecola was nearly 1,000 times higher than the value for one clone of A. pomi. Although the results from these trials did not indicate that either species had developed significant levels of resistance to the test materials, differences in LC₅₀ levels of >10-fold suggest insecticide tolerances and the possibility of control failures in the future. The demonstrated differences in susceptibility to insecticides between these two morphologically similar species also should be considered during the evaluation of new products for use on apple.

A larval immersion bioassay was developed to identify susceptibility of onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae), to chlorpyrifos and to determine whether this assay could be used to predict control in onion fields. Laboratory colonies were established from larvae collected in New York onion fields during 2003 and 2004, providing us with test insects to use in bioassays. The larval assay effectively determined susceptibility of D. antiqua to chlorpyrifos, and results were congruent with an adult bioassay. However, use of similar-aged larvae (4 d old) in the assays was critical because larvae became more tolerant to chlorpyrifos as they aged. In a field survey, six of the 13 populations had LC₅₀ values above the recommended field rate of 3,600 ppm (range 4,031–6,869). Over two successive seasons in the same field, susceptibility of D. antiqua to chlorpyrifos decreased in two of three fields (by 45 and 42%) and remained the same in another field, indicating that resistance is not predictable from year to year. Based on the relationship between damage in the field and LC₅₀ values from 11 of the populations mentioned above, all five populations that had LC₅₀ values above the field rate caused unacceptable levels of damage, whereas five of six populations that had LC₅₀ values below the field rate did not cause serious damage.

Maize, Zea mays L., has been transformed to express the Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis strain PS149B1. These two proteins act together as a binary insecticidal protein that is effective against corn rootworm (Coleoptera: Chrysomelidae) species. The design of the resistance management plan to preserve the long-term durability of this trait largely depends on the level of rootworm mortality induced by Cry34/35Ab1 corn rootworm-protected maize (frequently referred to as “dose” in this context). Here, we report on studies that showed Cry34/35Ab1-expressing maize event 59122 caused 99.1 to 99.98% mortality of western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae, after adjusting adult emergence numbers for density-dependent mortality. In two of three studies, there was a short delay in time to 50% adult emergence from 59122 maize plots compared with control plots, although emergence was completed at approximately the same time from both types of maize. These data support an expectation that alleles conferring resistance to the Cry34/35Ab1 proteins in western corn rootworm will be functionally nearly completely to completely recessive on 59122 maize and that there is unlikely to be assortative mating of Cry34/35Ab1-resistant and susceptible rootworms. When incorporated into simulation models of rootworm adaptation to transgenic maize, these findings suggest that a 20% refuge is likely to be highly effective at prolonging the durability of 59122 maize.

We investigated the genetic basis of adult behavioral response and larval physiological tolerance to permethrin within two diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), populations from Wooster and Celeryville, OH, with different average levels of larval tolerance. The adult behavioral response was measured as oviposition site preference and was investigated using full-sib design and parent-offspring regression. Additive genetic variance (0.134 ± 0.02) and the heritability (h² = 0.31 ± 0.08) for the behavioral response was significant for the Celeryville population, suggesting that in this population, a high proportion of phenotypic variation for adult behavioral response to permethrin was heritable genetic variation. The larval physiological response was measured with a topical application bioassay and was investigated using a half-sib design. Significant additive genetic variances and heritabilities for physiological tolerance to permethrin were detected in both populations. The genetic correlation between adult behavioral response and larval physiological tolerance to permethrin were negative, but significant only in the Celeryville population; indicating that adults from this population that are more behaviorally responsive produced offspring that are more susceptible to permethrin. Our findings have implications for the evolution and management of insecticide resistance in the diamondback moth. The adult behavioral response can lower the exposure of larvae to the insecticide, lowering selection pressure for physiological resistance in larvae. Furthermore, to the extent that the adult behavioral response increases fitness, it can indirectly select for larval susceptibility because of the negative correlation between the two traits.

We used computer simulations to examine evolution of resistance to the insect growth regulator (IGR) pyriproxyfen by the sweetpotato whitefly, Bemisia tabaci (Gennadius), biotype B [=Bemisia argentifolii (Bellows & Perring)]. Consistent with trends seen in cotton (Gossipyium spp.) fields in Arizona and Israel, results suggest that evolution of resistance to pyriproxyfen may occur rapidly in this haplodiploid insect. Similar to results from models of diploid insects, resistance evolved faster with increases in toxin concentration, dominance of resistance in females, the initial frequency of the resistance allele, and the proportion of the region treated with pyriproxyfen. Resistance was delayed by fitness costs associated with resistance. Movement between treated and untreated cotton fields had little effect, probably because untreated cotton leaves provided internal refuges in treated fields and whiteflies were controlled with other insecticides in external refuges. Resistance evolved faster when susceptibility to pyriproxyfen was greater in susceptible males than susceptible females. In contrast, resistance evolved slower when susceptibility to pyriproxyfen was greater in resistant males than resistant females. Results suggest that growers may be able to prolong the usefulness of pyriproxyfen by applying lower toxin concentrations and promoting susceptible populations in refuges.

I expanded the population dynamics and genetics model published in 2005 by Crowder and Onstad to include larval survival and movement to evaluate the role of mixtures of transgenic and nontransgenic corn, Zea mays L., seed for resistance management of western corn rootworm. I studied both density-independent and density-dependent toxin survival. In all but the worst-case scenarios, resistance did not evolve within 30 yr when the resistance allele, R, was recessive. The standard model with density-independent toxin survival based on the expression of a medium dose of toxin indicated that 50% R allele frequency will be reached by years 5 and 7, respectively, with dominant and partially recessive expression and 20% nontransgenic seed. The standard model with density-dependent toxin survival indicates that resistance will occur in year 5 under the same conditions. These results are similar to the published results of Crowder and Onstad who studied a model with adjacent block refuges and mostly nonrandom mating in the landscape (random only within each block). Results depended on the heterozygote advantage (differential survival between SS and RS) and the degree of random mating provided by the seed mixture.

Five adhesive traps and the Nzi cloth-target trap were compared to determine their trapping efficiency and biases for stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae). Two configurations of the BiteFree prototype trap, constructed of polyethylene terephthalate, were most efficient for trapping stable flies, whereas the EZ trap was least efficient. The two Alsynite traps, Broce and Olson, were intermediate to the BiteFree prototype and EZ traps. All adhesive traps collected a ratio of approximately two males for each female. Approximately 50% of the flies collected on the adhesive traps, both male and female, were blood fed, and 20% were vitellogenic. The Nzi trap collected an older component of the stable fly population, 81% blood fed and 62% vitellogenic, but it was much less efficient than the adhesive traps. The effectiveness of the BiteFree prototype trap indicates that materials other than Alsynite are attractive to stable flies.

In many insect species, females can mate more than once and store sperm from more than one male. An assessment and understanding of polyandry in the field can be important for pest species with a high colonization potential, such as the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which is also highly polyphagous and among the most destructive agricultural insects. The use of polymorphic microsatellite markers, combined with different statistical approaches, provides evidence that polyandry occurs in two C. capitata natural populations, one population from the Greek island of Chios and one population from Rehovot, in Israel. The observed different level of polyandry is discussed in relation to the genetic diversity, seasonality, and demography of the two populations. When polyandry is present, paternity analysis also indicates that one male, presumably the last, tends to sire most of the progeny. Polyandry and paternity skew may have important implications for the evolution of the species, in terms of maintenance of the genetic variability. Moreover, these aspects of the mating behavior, i.e., remating frequency and paternity skew, may locally affect the sterile insect technique, the most commonly applied control strategy against C. capitata.

The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), is a major pest of bread wheat, Triticum aestivum L. (em Thell), in most wheat-growing areas worldwide. Aphid-resistant cultivars are used to combat this pest, but very little is known about the molecular basis of resistance. In this study, differential gene expression in D. noxia biotype 1-resistant wheat plants containing the Dnx gene and D. noxia biotype 1 feeding on Dnx plants was investigated using suppressive subtraction hybridization. The derived subtracted cDNA library includes sequences similar to Pto and Pti1, genes involved in gene-for-gene recognition of and resistance to bacterial speck disease in tomato, Lycopersicon esculentum (L.). Pto- and Pti1-like sequences contain an activation domain with conserved amino acid residues crucial for avr protein recognition and binding by Pto, and avr-Pto phosphorylation of Pti1. Wheat defense signaling is represented by sequences putatively involved in producing sterols, jasmonates, Ca² , and abscisic and gibberellic acids. We suggest that reductions in populations of D. noxia fed Dnx plants are related to the expression of sequences involved in defensive chemical production, cellular transport, and exocytosis. Dnx plant tolerance of D. noxia feeding is proposed to be based on the expression of sequences putatively involved in self-defense against reactive oxygen species and toxins, and proteolysis; DNA, RNA, and protein synthesis; chloroplast and mitochondrial function; carbohydrate metabolism; and maintenance of cell homeostasis. D. noxia unsuccessfully counter Dnx by expressing sequences putatively involved in detoxification; proteolysis; DNA, RNA, protein, and lipid synthesis; carbohydrate metabolism; and mitochondrial function.

The southern chinch bug, Blissus insularis Barber (Hemiptera: Blissidae), is the most important insect pest of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, in Florida and other Gulf Coast states. Resistance to southern chinch bug was identified previously in St. Augustinegrass lines ‘FX-10’ and NUF-76. Choice and no-choice tests and ovipositional and developmental studies were conducted to determine the categories of resistance in FX-10 and NUF-76 to southern chinch bug. When adult chinch bugs had a choice among attached stolons of three susceptible lines (‘Floratam’, ‘Bitter Blue’, and ‘Palmetto’) and the two resistant lines, chinch bugs were found significantly more often over a 5-d period on the susceptible lines. This result indicates the presence of antixenosis in the resistant lines FX-10 and NUF-76. In a no-choice study, chinch bugs produced less than half as many excretory spots on FX-10 as on the susceptible lines. Significantly fewer excretory spots produced by chinch bugs confined on NUF-76 accumulated by days 3 and 5 after release; however, on the first 2 d, the accumulative number of excretory spots was not significantly less than that found on susceptible lines. The no-choice study confirmed a high level of antixenosis in FX-10, a moderate level of antixenosis in NUF-76, and possible antibiosis in NUF-76. Ovipositional and developmental studies were conducted using only Floratam (a widely planted cultivar that was formerly resistant to B. insularis) and the two resistant lines. Adults released on Floratam produced 11 and 5 times more eggs and 18 and 9 times more offspring than adults on FX-10 and NUF-76, respectively. Plant anatomical and biochemical studies are required to investigate the exact cause of antixenosis in FX-10 and NUF-76 and possible antibiosis in NUF-76.

Atherigona soccata (Rondani) (Diptera: Muscidae) is one of the most important pests of sorghum, Sorghum bicolor (L.) Moench, in Asia, Africa, and the Mediterranean Europe. Exploitation of cytoplasmic male sterility (CMS) for hybrid production has resulted in considerable narrowing of the genetic base and may increase the vulnerability of this crop to insect pests. Therefore, we studied the expression of different mechanisms of resistance in sorghum to A. soccata in CMS (A) and maintainer (B) lines of 12 genotypes under field and greenhouse conditions. The CMS lines of A. soccata-resistant genotypes were preferred for oviposition (78.5 versus 71.5% plants with eggs) and suffered greater deadheart incidence (47.6 versus 41.6%) than the corresponding maintainer lines, whereas such differences were not apparent in CMS lines belonging to the susceptible genotypes (92.7 versus 92.3% plants with eggs and 75.6 versus 74.6% deadhearts) under multichoice field conditions. Similar differences also were observed under controlled conditions in the greenhouse. The larval period (9.0 versus 8.8 d) and pupal mortality (18.4 versus 13.4%) were greater on maintainer lines than that on the CMS lines in the resistant group. The male and female pupal weights, fecundity, and antibiosis index were greater on the CMS than on the maintainer lines. The maintainer lines showed better recovery resistance than the CMS lines, but no such differences were observed in tiller deadhearts. The differences in susceptibility to A. soccata were greater in the A. soccata resistant CMS and maintainer lines than in the CMS and maintainer lines belonging to susceptible genotypes. Conversion of A. soccata-resistant genotypes into alternate less susceptible cytoplasmic backgrounds may be undertaken for developing sorghum hybrids with stable resistance to A. soccata.

Three grass host species—tall fescue, Festuca arundinacea Schreber; meadow fescue, Festuca pratensis Hudson; and perennial ryegrass, Lolium perenne L.—each infected with a number of different Neotyphodium endophyte isolates, were investigated for their effects on fall armyworm, Spodoptera frugiperda (J.E. Smith). Alkaloid profiles varied among associations. Choice and no-choice tests comparing feeding and early development of S. frugiperda larvae on endophyte-infected and endophyte-free leaf blade material were performed. Endophyte-mediated resistance to S. frugiperda was greatest in meadow fescue and weakest in tall fescue. Some endophyte isolates, particularly in perennial ryegrass and meadow fescue, had a major effect on feeding and development of S. frugiperda, whereas others had no effect or were only weakly efficacious. In tall fescue, some associations deterred S. frugiperda from feeding in choice tests but had no effect on development, whereas larvae reared on other associations weighed significantly more than control larvae fed endophyte-free grass. It was concluded that the deleterious consequences of endophyte infection were easily masked by other factors in tall fescue. Relative leaf age had no effect on feeding preferences in the three host species. Chemical analysis of herbage from the plants used, and results from a no-choice study using spiked artificial diets, failed to individually implicate any of the major known alkaloids (peramine, lolitrem B, ergovaline, and lolines) in the observed effects on S. frugiperda. Hypotheses explaining these observations, and their impact on creating desirable grass-endophyte associations for use in pastures, are discussed.

Host acceptance and population parameters of the aphid Illinoia pepperi (MacGillivray) (Hemiptera: Aphididae) were measured on highbush blueberry, Vaccinium corymbosum L. ‘Elliott’, and the wild species Vaccinium boreale Hall and Aalders, Vaccinium tenellum Aiton, Vaccinium pallidum Aiton, Vaccinium hirsutum Buckley, Vaccinium myrsinites Lamarck, and Vaccinium darrowi Camp. After 24 h of exposure, significantly fewer aphids remained in contact with V. boreale and V. hirsutum compared with V. corymbosum Elliott, V. darrowi, and V. pallidum. Length of the prereproductive period of I. pepperi was significantly longer on V. boreale and V. myrsinites, in contrast to V. corymbosum. Fecundity was also lower on V. boreale, V. hirsutum, V. myrsinites, and V. darrowi. Survivorship of I. pepperi 42 d after birth was significantly lower on V. hirsutum compared with the remaining Vaccinium spp. Reduced I. pepperi performance resulted in significantly lower intrinsic rate of increase (r_m) values being associated with V. myrsinites, V. boreale, V. hirsutum, and V. darrowi, compared with V. corymbosum. Net reproductive rate (R₀), generation time (T), and doubling time (T_d) of I. pepperi also were affected by the Vaccinium spp. Total phenolic and flavonol content varied between Vaccinium spp., with some high phenolic content Vaccinium spp. having reduced aphid performance. However, no significant correlation between phenolics and I. pepperi performance was detected. Results from this study identified several potential sources of aphid resistance traits in wild Vaccinium spp.

The influence of foliar glandular trichomes on developmental biology of the potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), was examined by selective removal of trichomes on resistant and susceptible potato germplasm comprising two glandular trichome-bearing genotypes (PI 473331 and PI 473334) of wild potato, Solanum berthaultii (Hawkes), two interspecific hybrids of S. berthaultii with Solanum tuberosum L. (Q174-2 and NY123), and two commercial S. tuberosum cultivars (‘Elba’ and ‘Allegany’). Adult mortality was affected, whereas nymphal emergence was unaffected by removal of glandular trichome exudates. No nymphs were observed emerging from leaves of PI 473331 or PI 473334. Regardless of the trichome removal treatment, no nymphs completed development on PI 473331, and only a small percentage of nymphs survived to adulthood on NY123 and PI 473334. PI 473331 had the greatest frequency of adults and nymphs with trichome exudate deposition on their bodies, followed by PI 473334. Nymphs, but not adults, had exudate accumulation when caged on foliage of Q174-2. Removal of type A trichome heads and type B droplets eliminated exudate deposition. The results of these studies provide evidence that phenolic oxidation chemistry and the physical barrier imposed by trichomes of S. berthaultii are responsible for much of the observed resistance but that other factors possibly linked to the presence of trichomes aid in the expression on resistance.

Tetranychus urticae Koch (Acari: Tetranychidae) is an important pest of clementine mandarins, Citrus reticulata Blanco, in Spain. As a first step toward the development of an integrated crop management program for clementines, dispersion patterns of T. urticae females were determined for different types of leaves and fruit. The study was carried out between 2001 and 2003 in different commercial clementine orchards in the provinces of Castelló and Tarragona (northeastern Spain). We found that symptomatic leaves (those exhibiting typical chlorotic spots) harbored 57.1% of the total mite counts. Furthermore, these leaves were representative of mite dynamics on other leaf types. Therefore, symptomatic leaves were selected as a sampling unit. Dispersion patterns generated by Taylor’s power law demonstrated the occurrence of aggregated patterns of spatial distribution (b > 1.21) on both leaves and fruit. Based on these results, the incidence (proportion of infested samples) and mean density relationship were developed. We found that optimal binomial sample sizes for estimating low populations of T. urticae on leaves (up to 0.2 female per leaf) were very large. Therefore, enumerative sampling would be more reliable within this range of T. urticae densities. However, binomial sampling was the only valid method for estimating mite density on fruit.

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic insect pest that is killing eastern hemlock, Tsuga canadensis (L.) Carrière, and Carolina hemlock, Tsuga caroliniana Engelmann, in the eastern United States. We used the sequential interval procedure to develop a binomial sequential sampling plan for A. tsugae sistens on individual eastern hemlock trees that uses nondestructive sampling of new shoots. The actual α (type I) and β (type II) error rates were essentially 5 and 10%, respectively. Tallies of new shoots infested by at least one A. tsugae sistens were compared with stop values for thresholds of 10 and 30% of new hemlock shoots infested. Twenty to 80 new shoots had to be examined per tree to render a low, high, or indeterminate classification, which took <2 min per tree regardless of the threshold used. This plan should be an efficient and cost-effective tool in the management of A. tsugae infestations on individual, high-value eastern hemlock trees.

Wandering phase Indianmeal moth, Plodia interpunctella (Hübner), larvae were exposed to the label rate of hydroprene (1.9 × 10⁻³ mg [AI]/cm²) sprayed on concreted petri dishes. Larvae were exposed for 1, 3, 6, 12, 18, 24, and 30 h and maintained at 16, 20, 24, 28, and 32°C and 57% RH until adult emergence. Larval developmental time and mortality were significantly influenced by temperature and exposure intervals. Maximum developmental time (47.2 ± 1.3 d) occurred at 16°C, and the minimum developmental time (7.0 ± 0.5 d) occurred at 32°C. Larval mortality generally increased at all of the five tested temperatures as exposure period increased. The greatest mortality (82.0 ± 0.1%) occurred when larvae were exposed for 30 h at 28°C, and minimum mortality (0.0 ± 0.5%) occurred at 16°C when larvae were exposed for 1 h. The relationships between temperature, exposure period, and developmental time were described by polynomial models, based on lack-of-fit tests. Hydroprene has potential to be an effective alternative to conventional insecticides in surface treatments for Indianmeal moth management. Response-surface models derived from this study can be used in simulation models to estimate the potential consequences of hydroprene on Indianmeal moth population dynamics.

Laboratory experiments were carried out to assess the insecticidal effect of the diatomaceous earth formulation SilicoSec against larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), in stored wheat (Triticum durum Desf.). Larvae were exposed to wheat treated with SilicoSec at 400 and 800 ppm and held at 20, 25, and 30°C and 55 and 75% RH. Larval mortality was assessed after 24 h, 48 h, 7 d, and 14 d of exposure in the treated wheat. At both dose rates, mortality increased with temperature, but this increase varied with the exposure interval. At short (≤48-h) exposures, larval mortality was significantly higher at 30°C than at the other two temperatures. In contrast, no significant differences were noted between 20 and 25°C. At longer exposures (≥7 d), the increase of temperature increased mortality at 800 ppm, but no significant differences were noted between 25 and 30°C at 400 ppm. Furthermore, significant differences in larval mortality were noted between the two humidity levels, but only at exposures ≥7 d. After 14 h of exposure, at both dose rates examined, the increase of temperature significantly decreased mortality. The results of the current study indicate that E. kuehniella is susceptible to SilicoSec, but temperature and relative humidity should be taken into consideration.