Water relations and desiccation tolerance of adults of five species of heliconiine butterflies were examined in laboratory studies. Percentage of total body water ranged from 63.25% in female Dryas iulia F. to 67.8% in male Heliconius charitonius L.; water content of females was less than that for males in all five species. Male and female H. hecale Hewitson and D. iulia had lower percentages of total body water than the other species and sexes. Cuticular permeability ranged from 30.71 ± 2.21 μg cm⁻²h⁻¹ mmHg⁻¹ in female D. iulia to 50.1 ± 15.5 μg cm⁻²h⁻¹mmHg⁻¹ in female H. charitonius using Meeh’s formula to estimate body surface area. Actual surface area measurements of butterflies were 12–15 times greater for a given body mass than surface areas calculated from Meeh’s formula. Mortality of butterflies exposed to 30°C and 0–2% RH ranged from 15% (female H. melpomene rosina Boisduval and H. hecale) to 60% (male H. cydno Bates). Time of death varied between 8.67 ± 2.0 h in male D. iulia and 11.3 ± 1.55 h in female H. hecale; percentage of total body water lost at time of death ranged from 30.97% in male H. charitonius to 39.45% in female H. cydno. Percentage of initial mass lost and percentage of total body water lost increased as a power function with desiccation time. The implications of water loss and desiccation tolerance to butterfly exhibits are discussed.

Using greenbugs, Schizaphis graminum (Rondani), as a host, the number of days required for development, survival, and sex ratio (female:male) were studied at five constant temperatures (10, 14, 18, 22, and 26°C) for colonies of Lysiphlebus testaceipes (Cresson) collected in south Texas, central Oklahoma, and central Nebraska. Developmental rate and lower development threshold were described by a linear function and compared among wasp colonies. The temperature thresholds for development from egg to adult for the Nebraska, Oklahoma, and Texas wasp colonies were estimated to be 5.64, 6.61, and 6.42°C, respectively; corresponding degree-day requirements for development were 181.2, 169.5, and 188.0 DD, respectively. No differences in developmental rate or lower development threshold estimates were observed among the wasp colonies. However, adult survival at 10°C was greater in the Nebraska colony, suggesting that there may be variation in the ability of L. testaceipes populations to tolerate and survive cold temperatures.

Dow AgroSciences has modified cotton plants (Gossypium hirsutum L.) by inserting a gene from Bacillus thuringiensis Berliner subsp. aizawai that produces an insect-active, full-length Cry1F delta-endotoxin, and is planning to commercialize insect-resistant cotton lines expressing this protein. These cotton lines control tobacco budworm, Heliothis virescens (F.), along with other lepidopteran larvae. A laboratory study was conducted to better understand the degradation of Cry1F protein in a representative soil from the midsouth cotton-growing area of the United States. Bioassay results with tobacco budworm were used to measure the relative titer of the protein in the soil after a series of incubation periods. Based on the decrease in toxicity over time, the half-life of the microbial Cry1F delta-endotoxin was estimated to be less than 1 d under laboratory conditions, indicating a rapid decay rate in soil.

We predict the future range of the fire ant Solenopsis invicta Buren within the United States based on climate and its current extreme distributions. To reach that goal, a dynamic model of colony growth with two time steps per day was formulated that operates by colony area, S, and alate production, a. Colony growth rate depended on daily maximum and minimum soil temperatures. Temperature records at 4,537 meteorological stations within the current (near 1.5 million km²) and potential range of S. invicta were obtained from NOAA’s National Climatic Data Center. At each station, a colony was allowed to grow and lifetime female alate production was calculated. Estimated alate production was then examined at current extremes of the fire ant distribution at selected locations in Arkansas, Tennessee, and Oklahoma. Estimates from these locations were used to define four zones of colony proliferation success: certain, possible, undemonstrated, and improbable. An annual precipitation limit (510 mm) was selected to indicate regions where arid conditions may prohibit growth in areas without supplemental water sources. Results of the model predict that S. invicta will likely move 80–150 km north in Oklahoma and Arkansas. It will also likely continue expanding into portions of Virginia, Maryland, and Delaware in the east and New Mexico, Arizona, California, Oregon, Nevada, and maybe even Washington and Utah in the west.

Both sexes of the noctuid moths Lacanobia subjuncta (Grote & Robinson), Mamestra configurata Walker (bertha armyworm) and Xestia c-nigrum (L.) (spotted cutworm) are attracted to the combination of acetic acid and 3-methyl-1-butanol (isoamyl alcohol). A controlled-release system for use of this attractant in traps was comprised of separate polypropylene vials for each chemical, with the chemical release rate delimited by a hole in the vial lid. When hole sizes for both acetic acid and 3-methyl-1-butanol were varied together, numbers of all three moth species trapped were greatest with vial hole diameters 1.0–3.0 mm. For all three species, captures of moths also were positively correlated with the ratio of acetic acid to 3-methyl-1-butanol vial hole sizes (acetic acid vial hole size was varied, 3-methyl-1-butanol vial hole size was held constant). Captures of these moths were not correlated with the ratio of 3-methyl-1-butanol/acetic acid vial hole sizes (3-methyl-1-butanol vial hole size varied, acetic acid vial hole size was held constant), over the range of hole sizes tested. Captures of L. subjuncta, M. configurata, and X. c-nigrum in a wet trap were significantly increased by the addition of boric acid to the trap drowning solution (to retard microbial growth and decomposition of specimens). In a comparison of different designs of traps baited with acetic acid and 3-methyl-1-butanol, greatest numbers of all three species were captured in a dry “bucket” trap which moths entered from near the trap top.

Collections of volatiles, ovipositor extracts, and electoantennography showed the sex pheromone of female currant borer moths, Synanthedon tipuliformis (Clerck), from Washington to be a 2-component (100:3) blend of (E,Z) -2, 13-octadecadienyl acetate and (E,Z) -3, 13-octadecadienyl acetate. Pheromone-baited sticky traps (rubber septa dispensers) captured male S. tipuliformis at one abandoned and two commercial red currant sites (one treated with insecticide, one untreated) in south central Washington from 19 May to 16 August 2000. Peak catches occurred during late May and June with up to 200–300 moths/trap/wk. Lowest numbers (overall mean: 4.8 ± 0.9 moths/trap/visit) were recorded at the insecticide-treated site and largest numbers (39.6 ± 5.5 moths/trap/visit) occurred at the untreated, commercial site.

Both sexes of the alfalfa looper moth, Autographa californica (Speyer), were captured in traps baited with chemicals and combinations of chemicals that are odorants from “moth-visited” flowers. When presented alone, phenylacetaldehyde was strongly attractive and benzyl acetate was more weakly attractive to alfalfa looper moths. Few alfalfa looper moths were captured in traps baited with cis-jasmone, linalool, phenethyl alcohol, benzyl acetate or benzyl alcohol. In a comparison of varied amounts of phenylacetaldehyde, accomplished by varying the diameter of the hole in the lid of vial dispensers, greatest captures of alfalfa looper moths occurred with the largest hole size tested, 6.3 mm in diameter. Catches of alfalfa looper moths were enhanced when phenylacetaldehyde was presented with cis-jasmone and when benzyl acetate was presented along with benzaldehyde, compared with these chemicals presented singly.

Landscape patterns of foraging activity in sympatric species of subterranean termites were examined. Foraging activity was observed biweekly within a grid of wooden monitoring stations covering an area of ≈900 m². The number and spatial distribution of active monitoring stations within the grid were used to determine seasonal patterns of foraging activity for each species. Gaps in the spatial distribution of occupied monitoring stations were quantified using the lacunarity index. Reticulitermes flavipes (Kollar) and Reticulitermes hageni Banks were observed within monitoring stations throughout the study. The number and spatial distribution of occupied monitoring stations varied seasonally. Seasonal patterns of activity and spatial distribution also varied between species. Lacunarity was highest for R. hageni during cool, wet months and highest for R. flavipes during hot, dry months. Seasonal changes in the number of active monitoring stations and their spatial distribution in the landscape were correlated with seasonal changes in soil temperature and soil moisture for both species. These patterns reflect differential degrees of adaptation to soil moisture and temperature extremes and could provide a mechanism for resource partitioning within the three-dimensional soil landscape.

Life-history traits correlated to reproduction are important in deciding adaptability of insects. Lagria hirta L. has a short phytophagous adult phase in summer and a very long saprophagous larval phase extending from autumn until spring. This study revealed that its reproduction was modified by external factors and by complex interactions involving different life-history traits. Oviposition occurred only at 15–25°C, LD (L16: D8) or SD (L8: D16). Within this temperature range, preoviposition time, fecundity and adult life span were affected (P ≤ 0.05). Photoperiod was found significantly to affect fecundity, viability of eggs and preoviposition time (P ≤ 0.04). Unmated females can lay eggs, but the eggs are sterile. The survival of eggs is also influenced by photoperiod (P < 0.001). In this study, the subtle variations were examined in the last instar’s duration, pupal weight, fecundity and adult life span. In terms of reproduction, two correlations were apparent: larval short last instar durations result in heavier pupae and eclose to longer-lived adults; conversely, larvae with longer last instars produce lighter pupae which, if female, tend to lay fewer eggs. These correlations were statistically significant (P ≤ 0.05). These trends represent a trade-off in resource allocation: long final instar duration may consume more energy that would be invested in reproduction. This is heterogeneous (phenotypically or genotypically) among the individuals of L. hirta.

We modeled development in grape berry moth, Endopiza viteana (Clemens), which exploits wild and cultivated Vitis. Laboratory experiments were used to derive the temperature-dependent developmental curve for eggs, larvae, and pupae. We used linear interpolation to estimate stage-specific base temperature thresholds and degree-day requirements under laboratory conditions. We also estimated parameters of the Logan and Lactin nonlinear developmental models. Lastly, we conducted field experiments to evaluate the conventional degree-day model, which has a base threshold of 10°C; an improved degree-day model that was based on our laboratory observations; and nonlinear developmental models in predicting seasonal grape berry moth development. We concluded that the Logan nonlinear model provided the best estimates of grape berry moth field development, and an improved degree-day model should use 8.41°C as a minimum base temperature threshold and 423.9 as the egg-to-adult degree-day requirement. Also, after comparing degree-day accumulation estimates using the maximum-minimum method and trapezoidal integration to hourly temperature measurements, we concluded that the two approaches provided similar estimates during June–September.

To observe the aggregation and dispersal behavior of adult European corn borer, Ostrinia nubilalis (Hübner), males in search of mates, two populations were marked, each with a different dye. One population was continuously reared in the laboratory (>5 yr) and the other was collected annually from the field. From 1986 to 1988, marked adults were released in two release sets per year, with three to five releases per release set, coinciding with the spring and summer flights of European corn borer in central Iowa. Traps for recapture contained lures baited with 40 μg of synthetic 97:3 Z:E-11-tetradecenyl acetate. Traplines extended from 200 m to 48 km. Each trap was assigned a compass direction. Males from the laboratory-reared population dispersed similarly to males just 1 generation from the wild. European corn borer males and females dispersed 23–49 km and some were recovered 14 km from the release site within 100 min after release. Sampling of aggregation sites demonstrated that on the nights of release, many adults aggregated in adjacent dense vegetation and did not disperse until the following night. Upon dispersal, these adults seemingly moved many meters or kilometers before settling again. Recapture of marked adults at 200 m might have been influenced by open landscapes (short, vegetative-growth corn). Recapture at 800 m or beyond, however, was unaffected by open landscapes, and in 1988 a greater proportion of marked males was recaptured while the landscape was closed. (tall, mature-growth corn). In 1987, during the first flight of European corn borer, displacement to 800 m was southeasterly, south, or west, but during first flights in 1986 and 1988, displacement to 800 m was predominately northeasterly. During the second flight in midsummer, displacement to 800 m for all 3 yr of the study also was northeasterly. Recapture results from 1986 suggest that male movement >800 m is common. During the first release set (early summer), 37% of the males recaptured flew 800 m or more and 8% flew 3.2 km or more. During the second release set (late summer), 51% of the males recaptured flew 800 m or more and 11% flew 3.2 km or more. The recommendation for placement of nontransgenic corn (Zea mays L.) as refuge in the Corn Belt is a half mile or closer to Bacillus thuringiensis Berliner (Bt)-corn if the refuge corn is not sprayed and a quarter mile or closer when the refuge corn is sprayed. Based on the dispersal results from this study, at least in Iowa, a half-mile proximity recommendation should be robust. Studies still should be conducted in other regions, especially where corn is commonly irrigated, to determine whether European corn borer adult movement patterns are similar.

Applications of two doses of an internal physiological marker, rubidium, were applied as foliar solutions of rubidium chloride (RbCl) to field plots of cotton, Gossypium hirsutum L., and grain sorghum, Sorghum bicolor (L.) Moench, to determine the potential of this technique for detecting intercrop movement of generalist predators. Because artificially elevated rubidium levels of marked plants and insects decline with time, three applications were made at distinct phenological stages of grain sorghum to test if multiple mark-recapture experiments could be conducted at the same sites. Samples of predators and plant tissues were made at the onset of each sampling period and every 2 d through 6 d after RbCl application. Results showed that both crops, as well as all arthropod predators tested, exhibited significant elevation of rubidium levels over field-collected controls. Further, the effectiveness of the mark did not differ between crops, indicating that one set of protocols is sufficient for marking in both crops. No differences in mark effectiveness were detected between doses until the last sampling period, 6 d after mark application, and then only in one of three taxa. Using this method, we detected predator movement between crops, and the percentage of positive recaptures (>6%) was higher than those in similar studies using different marking systems. These results collectively suggest that this method can be used to elucidate the relationship between predator populations in these crops, and that it is potentially applicable to other multiple-crop agroecosystems.

RESUMEN Aplicaciones foliares de rubidio, un marcador fisiológico interno, en soluciones de cloruro de rubidio (RbCl) a dos concentraciones fueron hechas en parcelas de campo de algodón, Gossypium hirtusum L., y sorgo, Sorghum bicolor (L.) Moench, para determinar el potencial de esta técnica en el estudio del movimiento entre cultivos, de depredadores generalistas comunes a ambos. Tres aplicaciones fueron hechas a distintas etapas fisiológicas del sorgo para determinar si varias pruebas de marca-recaptura pueden ser conducidas en sitios similares. Muestras de plantas y de artrópodos depredadores fueron tomadas al comienzo de cada prueba y cada dos dias hasta seis dias despues de cada aplicación de RbCl. Resultados mostraron que en ambos cultivos y en todos los artrópodos depredadores que se analizaron, los niveles de rubidio fueron significativamente elevados en comparación a controles de campo y que la efectividad de la marca no varió entre cultivos, indicando que un solo procedimiento es suficiente para marcar en ambos cultivos. No se detectaron diferencias en la efectividad de la marca entre las dos concentraciones usadas hasta el ultimo muestreo, seis dias despues de la aplicación, y solo en uno de los tres grupos taxónomicos examinados. La recolección de depredadores con marca positiva en parcelas cercanas no tratadas, indicó que la marca fue suficiente para detectar el movimiento de depredadores de un cultivo a otro. El porcentage de recapturas positivas fue mas alto (>6%) que en estudios similares previos. Estos resultados colectivamente sugieren que este método ayudará a aclarar la relación entre poblaciones de depredadores en estos cultivos y que es potencialmente aplicable a otros agro-ecosistemas de cultivos multiples.

Developmental rates of the B- and Q-biotypes of Bemisia tabaci (Gennadius, 1889) were studied at seven constant temperatures (17, 20, 23, 26, 30, 33, and 35°C) on sweet pepper, Capsicum annuum L. (‘Morrón’). The egg incubation period and the times required to complete development at all immature stages decreased with increasing temperature up to 33°C, but at 35°C were found to be greater than at 33°C. The relationships between developmental rate of B. tabaci and temperature were influenced by the insect biotype. The lower and upper developmental thresholds as well as the optimal temperatures and thermal constant for the preoviposition period and all immature stages were estimated by fitting the observed developmental rates versus temperature with a nonlinear model and two linear models. For all stages, graphs obtained by plotting the reciprocal of development times against temperature could be described by the modification 2 of the Logan’s model. The simple linear model tT = K ct suffices for predicting B- and Q-biotype phenologies on sweet pepper for the temperature range of 17–33°C. The shortest developmental times as well as the lowest developmental thresholds and thermal constant were mostly obtained with the Q-biotype. Overall, the most favorable temperature range appeared to be 31–33°C. Mean generation times (adult-adult) ranged from 17 d (Q-biotype) and 18 d (B-biotype) at 33°C to 49 d (B-biotype) and 46 d (Q-biotype) at 17°C.

Studies in New York and Pennsylvania compared egg mass recruitment and larval survival on corn and other hosts of the European corn borer, Ostrinia nubilalis (H[umlaut]ubner), to assess the potential of these plants to act as a refuge in a resistance management program. Assessments were made on replicated plantings and natural plant stands in the field and under controlled conditions in the laboratory. Scouting of mixed field plantings revealed more egg masses on corn than any other crop or weed species. At least twice as many larvae per plant were recovered from naturally infested corn compared with the next best host plant across both years. Larval recovery from noncorn host plants varied widely. Fewer adults emerged from overwintering weed stubble than from corn stubble, and the parasitoid Macrocentris grandii (Goidanich) was found associated only with corn stubble. Survival on plants infested with corn borer larvae was consistently higher on corn than on other plants. In a laboratory study, the number of corn borer tunnels in corn was double the next best host, ragweed. Noncorn hosts appear unlikely to provide a substantial number of corn borer individuals susceptible to B. thuringiensis (Berliner) in comparison with the number expected from the 20% planting refuge mandated by EPA registration of Bt-corn. Evidence from these studies do not support a recommendation of reduced refuge planting areas in the northeastern United States.

During 1991–1993 and 1998–1999, a leafblotch miner, Micrurapteryx salicifoliella (Chambers), infested willows (Salix spp.) throughout a vast area in drainages of the Yukon and Kuskokwim Rivers, AK. The insect’s biology had not been studied and it was unknown from Alaska. Eggs were laid singly, cemented to the epidermis of undersides of leaves. Hatched larvae mined directly into leaves beneath the chorion. Five instars occurred. Mining by the first three instars created little external evidence of their presence. Fourth and fifth instars, however, created conspicuous necrotic, reddish, blotches that often covered the upper leaf surface of susceptible host willows. Mature larvae exited through slits made on the undersides of leaves and spun cocoons on either leaf surface before pupating from mid-July into August. Adults emerged in late July and August and overwintered in that stage. Ten species of willows were infested, severity of which differed somewhat between localities and species. Feltleaf willow, S. alaxensis (Andersson) Coville, was not infested, apparently due to its under leaf surface being covered by a protective felt-like mat of hairs that prevented attachment of eggs to the epidermis, a condition deemed to be critical to survival of larvae upon hatching.

The Argentine ant, Linepithema humile (Mayr), is native to South America and invasive in many parts of the world, including North America. Various morphological forms of L. humile exist in South America, and it is possible that some forms may comprise distinct species. In Brazil, L. humile is reported to be attacked by parasitoids in the genus Pseudacteon (Diptera: Phoridae). If Pseudacteon parasitoids attack the invasive form of L. humile, they may be candidates for biological control of this ant. We compared body size, scape length, and pronotal pilosity among populations of L. humile that were attacked by parasitoids and those that lacked parasitoids. Ants that hosted parasitoids at foraging trails in Brazil tended to have more pronotal hairs and shorter scapes than ants that did not host parasitoids in Brazil, Argentina, and North America. We used paired experimental trials to determine whether phorid parasitoids exhibit narrow host specificity or whether they will attack the invasive form of L. humile if given the opportunity. Parasitoids located their natural host form but did not locate either North American L. humile or morphologically similar ants from Brazil. Together these results suggest that various forms previously treated as L. humile are in fact separate species, that L. humile is not a natural host of the parasitoids studied here, and that these parasitoids are not candidates for biological control of Argentine ants in North America.

The cottonwood leaf beetle, Chrysomela scripta F., is the most serious defoliator of young plantation-grown Populus in the eastern United States, yet there is a paucity of data on larval feeding performance across Populus clones used in tree breeding. Field experiments were conducted in 1998 and 1999 to determine the overall feeding performance of larval C. scripta on 8 Populus selections from a pedigree family. Using a randomized complete block design, entire trees were enclosed in mesh cages, and female C. scripta were allowed to oviposit in sleeve cages on each tree. Larval cohorts were culled to 10 upon hatch and allowed to develop to pupation within each sleeve cage. Larval survival, pupal weight, adult emergence, and total mortality were recorded as performance parameters. Significant but inconsistent performance differences were found among clones, suggesting that some clones were less suitable for C. scripta larval development in some insect generations. Larval performance was generally poorer on clones with higher P. trichocarpa parentage. C. scripta performance was significantly poorer in 1999 and showed a decline throughout the 1999 growing season, but it is not clear whether this was caused by conditions of the host plants, weather patterns, or changes made in the source of insects for infestation. Clones with foliar characteristics detrimental to larval C. scripta performance could be used for plantings or in developing C. scripta-resistant hybrid Populus selections for short-rotation woody crop systems.

Population dynamics of colonies of the mymecophilous leafhopper Dalbulus quinquenotatus DeLong & Nault were recorded in the laboratory in the presence and absence of the tending ant, Formica fusca (L.). These experiments used colonies of leafhoppers started with five male and five female adults on a single Tripsacum dactyloides L. plant. The first experiment consisted of eight leafhopper colonies, four with tending ants and four without. The second experiment used 16 leafhopper colonies, eight with tending ants and eight without, with four of each of these ant treatments also with Nabis americoferus Carayon predators. The numbers of young nymphs, older nymphs, and adult leafhoppers, along with host plant condition were recorded every 2–3 d for 62 d for both experiments. Nontended leafhopper colonies exploded and overwhelmed their host plants, killing them in an average of 39.0 d, resulting in the extirpation of those leafhopper colonies. Ants maintained leafhopper colonies by regulating population dynamics, with colonies of leafhoppers tended by ants being significantly smaller (P < 0.02) and developing from egg to adult significantly slower (P < 0.001) than colonies of nontended leafhoppers. Ant-tended leafhopper colonies did not overwhelm their host plants during either experiment, as the ants removed excess honeydew and leafhopper exuvia, thus maintaining a constant supply of honeydew. Ants were observed protecting leafhoppers from nabid predators, although this protection did not significantly influence leafhopper population size or length of egg to adult development.

Season-long field studies were conducted in Washington apple orchards that compared the following: (1) twice per week releases of partially sterile codling moths, Cydia pomonella (L.), treated with either 100 or 250 Gy, and (2) combinations of mating disruption plus the release of partially sterile (100 Gy) codling moths, to control wild codling moth populations. No significant differences in the level of fruit damage at either midseason or harvest were found between any of the treatments, or between the treatments and the inside controls. Damage in all plots was <0.1%. In both studies, trap data suggest that the movement of the 100 Gy-treated moths into the other treatments and the inside controls may have masked treatment effects. However, fruit damage was significantly lower in all treatment plots when compared with control plots located outside of the treatment areas. Results indicated that the release of partially sterile male (and fully sterile female) codling moths does not result in increased fruit injury and that the lower dose of radiation used to partially sterilize males results in insects that are more active, disperse greater distances and are generally more competitive.

The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is a pest of rice in the seven rice producing states of the United States and several countries where it has been introduced. Carbofuran was used adequately for nearly 30 yr, but it is no longer registered for use in rice and has been replaced by λ-cyhalothrin (Karate) and diflubenzuron (Dimilin). The scouting methods for carbofuran were inadequate or too late in determining the need for insecticide applications of the newer insecticides. Therefore, a new population monitoring method was developed using a double-ended aquatic barrier trap. The trap function was based on weevil swimming behavior, and 16 barrier trap prototypes were tested on adult weevils, 22–23 July 1998, in a small bay of late planted rice. Adult means ± SE were 73.9 ± 9.4 per trap on 23 July 1998 and 54.4 ± 6.4 per trap on 24 July 1998. The core sample mean for this plot was 72.9 ± 7.0 larvae per core. The trap was tested in both commercial fields and early and late planted small bays in 1999. Larval weevil infestations ranged from moderate (near or slightly below the economic injury level (EIL) to high (62.8 per core). Regression analyses showed a significant correlation between adults captured in traps to subsequent larval density in field edges (r² = 0.98) and field interiors (r² = 0.92). For every 1.0 rice water weevil adult captured in barrier traps, a density of 1.2–2.8 larvae per core sample was predicted. The aquatic barrier traps caught adult weevils without lures. Trapping rice water weevil adults immediately after permanent flood in drill-seeded fields can be used to aid decision making for insecticide application in rice.

There is considerable interest in using pheromone trap catches of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), to estimate or predict population density and damage. At six sites in the Georgia Piedmont, adult tip moths were monitored through one or more years using pheromone traps while population density and damage for each tip moth generation were determined. During most years, trap catch was higher during the first adult generation compared with subsequent generations regardless of population density. Within each generation, trap catch was moderately to highly correlated with associated population density or damage levels. Hyperbolic regression models best described these relationships and suggested trap saturation when populations are high. Trap catch during the first adult generation was highly predictive of population density or damage during the subsequent generation. Trap catch during the second adult generation was fair at predicting subsequent density or damage. The models presented herein should be used with caution because they are likely to be region-specific. Validation of these relationships is necessary before widespread application of these models is warranted.

Four treatments were evaluated during 1997 and 1998 to determine the effects of pesticides on coccinellid densities: (1) untreated control, (2) foliar applications of a systemic insecticide, imidacloprid (Provado 1.6 F), when spray thresholds of aphid numbers were exceeded in all plots, (3) weekly foliar applications of a fungicide, chlorothalonil (Bravo 720), and (4) weekly foliar applications of imidacloprid (Provado 1.6 F). The coccinellids observed in Georgia cotton during the study included Hippodamia convergens Guérin-Méneville, Scymnus spp., Harmonia axyridis (Pallas), Coccinella septempunctata L., and Coleomegilla maculata (Mulsant). During 1997, H. convergens and Scymnus spp. comprised 75 and 15%, respectively, of all coccinellids observed during the study. During 1998, Scymnus spp. comprised 44% of all coccinellids, and H. convergens comprised 33%. Coccinellid population densities closely tracked those of cotton aphids during both years. Cotton aphid and coccinellid densities were greatest in the chlorothalonil treatment during both years of the study. In functional feeding response experiments, fourth-instar and adult Scynmus creperus exhibited a type II functional response to A. gossypii density under laboratory conditions. Fourth instars exhibited a higher search rate and shorter handling time than adult S. creperus. Collectively, coccinellids are a valuable component of the cotton aphid’s natural enemy complex.

The insect growth regulator (IGR), diflubenzuron (Dimilin 2L), was evaluated for its effect on development of Copidosoma floridanum (Ashmead) and its host, Pseudoplusia includens (Walker), when applied at 0.035 kg ai/ha to soybean, Glycine max (L.), a rate used in preventive programs for control of velvetbean caterpillar, Anticarsia gemmatalis Hübner. Parasitized and nonparasitized soybean looper larvae were fed either diflubenzuron-treated or nontreated foliage. The feeding period of parasitized larvae was 1.7 and 1.8 d longer on diflubenzuron-treated and nontreated foliage, respectively, than that of nonparasitized larvae. Pupation period of C. floridanum and soybean looper was not significantly influenced by diflubenzuron. Although parasitized soybean looper fed both foliage treatments experienced 100% mortality, nonparasitized soybean looper fed nontreated foliage was 23.2% and nonparasitized soybean looper fed diflubenzuron-treated foliage was 12.2%. Parasitized soybean looper fed nontreated foliage consumed 19.2% more leaf area than nonparasitized larvae fed nontreated foliage, whereas parasitized soybean looper fed diflubenzuron-treated foliage consumed 21.2% more leaf area than nonparasitized larvae on the same foliage. There was no significant difference in number of parasitoids emerging from host mummies among treatments; however, there was a positive correlation between leaf area consumed and adult parasitoids per mummy. Diflubenzuron does not appear to produce deleterious effects in C. floridanum or its host, soybean looper, at the current rate used for management of other lepidopteran pests.