Performance of insect vectors can be influenced by the viruses they transmit, either directly by infection of the vectors or indirectly via infection of the host plants. Southern rice black-streaked dwarf virus (SRBSDV) is a propagative virus transmitted by the white-backed planthopper, Sogatella furcifera (Hovath). To elucidate the influence of SRBSDV on the performance of white-backed planthopper, life parameters of viruliferous and nonviruliferous white-backed planthopper fed rice seedlings infected or noninfected with SRBSDV were measured using a factorial design. Regardless of the infection status of the rice plant host, viruliferous white-backed planthopper nymphs took longer to develop from nymph to adult than did nonviruliferous nymphs. Viruliferous white-backed planthopper females deposited fewer eggs than nonviruliferous females and both viruliferous and nonviruliferous white-backed planthopper females laid fewer eggs on infected than on noninfected plants. Longevity of white-backed planthopper females was also affected by the infection status of the rice plant and white-backed planthopper. Nonviruliferous white-backed planthopper females that fed on infected rice plants lived longer than the other three treatment groups. These results indicate that the performance of white-backed planthopper is affected by SRBSDV either directly (by infection of white-backed planthopper) or indirectly (by infection of rice plant). The extended development of viruliferous nymphs and the prolonged life span of nonviruliferous adults on infected plants may increase their likelihood of transmitting virus, which would increase virus spread.

While morphological identification of thrips species has been difficult because of their minute size and a lack of easily recognizable characteristics, molecular identification based on the development of specific molecular markers can be easily and reliably carried out. Among the known molecular markers, the nuclear internal transcribed spacer (ITS) exhibits distinguishable variations among thrips species. In this study, sequences of ITS2 region of 10 agriculturally important thrips were established to design species-specific primers for polymerase chain reaction (PCR). ITS2 sequence variations within these species were far less than those among species, indicating the suitability of this marker for species-specific primers design. These primers, though with one or two sporadically variable positions, showed a good efficacy within species. The specificity of these primers, examined on thrips species belonging to 15 genera, proved satisfactory. Furthermore, a multiplex PCR was used successfully for identifying Frankliniella occidentalis (Pergande), an insect pest monitored for quarantine purpose, and three additional thrips also commonly found in imported agricultural products and field samples, i.e., Thrips tabaci Lindeman, Thrips hawaiiensis (Morgan), and Frankliniella intonsa (Trybom). This study has demonstrated that specific primers and multiplex PCR based on ITS2 are reliable, convenient, and diagnostic tool to discriminate thrips species of quarantine and agricultural importance.

We determined the virulence and insecticidal activity of the hypocrealean fungus Metarhizium brunneum (Petch) strain EAMb 09/01-Su and its crude extract against Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae) and we evaluated the combined use of the fungus with its crude extract. We also determined the effect of fermentation time, temperature, and initial pH of the M. brunneum culture medium on the insecticidal activity of the crude extract. When C. capitata adults were sprayed with a conidial suspension, the strain EAMb 09/01-Su caused 100% mortality with a mean lethal time (LT₅₀) of 5.6 d and mean lethal concentration (LC₅₀) of 2.84 × 10⁷ conidia per milliliter. Fermentation time significantly affected the lethality of the crude extract when it was provided to C. capitata per os. The highest level of mortality (73.3%) and the shortest median survival time (25.5 h) was obtained from 15-d-old cultures. The crude extract was demonstrated to be thermostable, given that the mortality was >50% at 48 h when the extract had been heated to 100°C for 3 h. Lastly, the optimum initial pH for maximum crude extract activity in terms of mortality ranged between 7 and 9. Additivity was observed for all M. brunneum EAMb 09/01-Su strain crude extract combinations tested, indicating compatibility between products. We concluded that the M. brunneum EAMb 09/01-Su strain is a promising tool for medfly control alone or in combination with its crude extract.

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is an endemic pest in Israel and there can be low levels of infestation of dates (Phoenix dactylifera L.). Because C. capitata is considered a quarantine pest by several major importing countries, the export of fresh dates requires the elimination of this pest. For mandarin, cold storage at 1.11°C for 15 d is considered to be an effective treatment for the elimination of C. capitata. In this study, we compared the cold tolerance of C. capitata in ‘Barhi’ dates to that of C. capitata in mandarins (Citrus unshiu Marcovitch, ‘Satsuma’). In Barhi dates, we found the third instars to be the most cold-tolerant as compared with other life stages. Ceratitis capitata in date fruits were significantly less cold-tolerant than C. capitata in Satsuma mandarins. The last viable larvae in dates and mandarins were found after 8 and 13 d of treatment, respectively, and the calculated mortality curves in the two crops were significantly different. These results demonstrate that C. capitata is more sensitive to cold treatment when in date fruits than in mandarins. Therefore, the quarantine cold treatments used to eliminate C. capitata from mandarins should be sufficiently effective if applied to fresh date fruits.

The suitability of mature green ‘Maradol’ papaya as a host of Anastrepha ludens (Loew) was studied under field and laboratory conditions. Field tests were conducted on commercial-ripened and spot-ripened fruit in two orchards and during two seasons in the state of Chiapas. Fruits at exportation ripeness are in “commercial ripeness,” while fruits that are harvested immediately preceding exportation ripeness are in “spot ripeness.” The field tests consisted of forced infestation experiments that evaluated papayas at two ripeness stages: the commercial- or exportation-ripened fruit (green fruits with one or two yellow stripes) and fruit before exportation ripeness called “spot ripeness.” These tests were conducted in two orchards and during two seasons in the state of Chiapas, Mexico. Laboratory trials were performed with commercial-ripened fruit only. Fruit from four different postharvest periods (3, 24, 48, and 72 h) were exposed to groups of gravid flies. No larvae emerged from the fruit that was collected in the field experiments. However, some larvae and several fertile flies were obtained from the commercial-ripened fruit 72 h postharvest but not 3, 24, and 48 h postharvest in the laboratory. The results of this study indicate that the commercially ripe fruits of papaya Maradol were resistant to or free from infestation of A. ludens flies under field conditions, though these fruits must be considered nonnatural, conditional host because they became infested in the laboratory.

Although many reports suggested the economic importance of the red imported fire ant, Solenopsis invicta Buren, few attempts to test the hypothesis that the red imported fire ant-aphid mutualism enhances the occurrence of red imported fire ant on crops, thereby interfering with their flowering and fruiting and affecting their output. To address this problem, we compare the effects of red imported fire ant on the flowering and fruiting of self-pollinating and cross-pollinating crops by field investigations and indoor experiments. In the field, our results revealed that regardless of the aphid interaction, red imported fire ant preferred flowering mungbean plants, and their activities decreased the yields of single plants, total pod number, kernel number, and kernel weight. The interaction of red imported fire ant and aphids generated unfavorable effects on rapeseed yields per plant, total pod number, grain number, grain weight, and thousand-kernel weight and stimulated an elevated proportion of malformed seeds. However, the differences were not significant if only red imported fire ant was present. In the laboratory, although red imported fire ant display no apparent preference toward the seedlings of mungbean or rapeseed, the ants clearly favor the flowering plants of mungbeans. Therefore, this study indicated that one of the main mechanisms whereby red imported fire ants affect the crop yield is by compromising the reproduction processes.

Tuta absoluta (Meyrick), a tomato leaf miner, is one of the destructive pests of tomatoes, which is native to South America, and has been considered as a quarantined pest for Iran since 2010 while it has quickly spread all around the country and is known as a key pest in tomato-cultured regions since 2012. In the current study, the life table parameters of T. absoluta were studied on cut leaves of three greenhouse cultivars of tomato including ‘Atabay’, ‘Cluse’, and ‘Perenses’. Data were analyzed based on the age-stage, two-sex life table analysis. Results showed differences in the duration of egg, larvae, pupae, and adults. Meanwhile, the life table parameters including intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R₀), and gross reproductive rate (GRR) were categorized increasingly based on the feeding on Cluse, Atabay, and Perenses, respectively. The findings of the current study showed that the Cluse could be nominated as an unsuitable host for tomato leaf miner among cultivars because of its negative influences on the pest’s biological parameters. Moreover, these results may develop the finding and screening process of relatively resistant cultivars to be used in the management of T. absoluta.

The spotted wing drosophila, Drosophila suzukii Matsumura, has widely established in North America and become an economic concern for a variety of fruit crops. To better understand fruit susceptibility, we evaluated peach surface characteristics on the pest's oviposition success. The number of D. suzukii eggs laid into the fruit flesh was tested on 1) peaches with or without indumenta (commonly referred to as peach fuzz), 2) peaches physically damaged by harvest operations, 3) peaches damaged by the peach twig borer Anarsia lineatella Zeller or the forktailed bush katydid, Scudderia furcata Brunner von Wattenwyl, and 4) peaches with punctures that simulated stink bug damage. Female D. suzukii did not lay eggs in intact fuzzy sections of the fruit or into small punctures (0.3 or 0.5 mm), but readily laid eggs in sections without fuzz, with insect damage, and with large punctures (1 mm). The number of eggs per treatment was positively related to the area of the damaged section; the overall fruit firmness and sugar content was not related to the number of eggs laid in treated or damaged spots. Direct observations of D. suzukii oviposition confirmed that peach fuzz appeared to be an obstacle for the fly's oviposition success, and female flies ceased ovipositional attempts on fuzzy peach sections after a short period of time. Successful oviposition times were associated with substrate firmness, with shorter oviposition time in damaged spots than in cherry fruit or shaved spots of the peach. The results indicate that intact, preharvest peach fruit are unlikely to be infested by the fly, but any surface damage could render the fruit susceptible to the fly.

Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) were colonized so that larval growth rates could be compared. Colonies were also established to provide insight into the protein needs of adult C. rufifacies and developmental rates of the ensuing larvae. The C. megacephala and C. rufifacies laboratory colonies were reared for five and six generations, respectively, at 28°C. C. megacephala developmental mean rate from egg to adult was 20.4 ± 0.38 d. First-instar larvae emerge in 1.4 ± 0.24 d, second-instar larvae develop in 2.6 ± 0.38 d and third instars occur at 6.3 ± 0.72 d. Development from egg to pupation occurred in 12 ± 1.10 d. C. rufifacies developed at a mean rate of 16.2 ± 0.78 d from egg to adult emergence. Each stage occurred in succession from first-instar larvae 1.1 ± 0.25 d, second-instar larvae developed 2.3 ± 0.25 d later, and the third-instar larvae developed 5.7 ± 0.41 d later. The larvae pupated 10.0 ± 0.57 d after oviposition. Both of these flies can be collected in the wild and easily colonized using conditioned chicken as an oviposition and larval medium. C. megacephaïa apparently prefers a lower development and maintenance temperature than C. rufifacies, as evidenced by the high pupal mortality. Laboratory-reared C. rufifacies benefited from bloodmeal as a protein supplement to enhance egg production. C. rufifacies larvae were not observed preying on each other and additional larval species were not provided to serve as prey.

The bean bug, Riptortus pedestris (F.) (Hemiptera: Alydidae) is one of the most important pests of soybean (Glycine max L. Merrill) in Korea and Japan. R. pedestris is known to appear early in spring when leguminous seeds such as soybean are not available. Because soybean has been reported to be the most important food source for R. pedestris development, in this study, we assessed the effect of this period of soybean deprivation during the nymphal stage on the development and reproduction of R. pedestris and on egg parasitism by its two egg parasitoids. More than 50% of the R. pedestris population tested survived on barley, even when they did not start feeding on soybean until the fourth instar. Nevertheless, R. pedestris nymphs deprived of soybean developed more slowly and became smaller adults than those provided with soybean. However, no difference was observed in the preovipositional period or fecundity between these groups. In addition, neither the hatch nor the egg parasitism rate by two egg parasitoids was affected by the presence or absence of soybeans in the nymphal diet. This study indicates that R. pedestris nymphs can develop successfully even when lacking this important food source in early life, and that adult reproduction is not affected by the quality of diet ingested during the nymphal period.

The Oriental Fruit Moth Grapholita molesta (Busck) causes substantial damage to stone and pome fruit crops worldwide. Light-based traps offer a potential means for pest monitoring and management. In this study, we tested the preference of G. molesta for the following light sources: monochromatic light produced from light-emitting diodes (LEDs) (red, orange, yellow, green, blue, violet, and white), specific wavelengths of light produced from filters (405, 450, 480, 512, 540, 576, and 610 nm), and polychromatic light produced by different numbers (0, 12, 24, and 36) of green, blue, and violet LEDs. The arrangement of polychromatic lights was based on an orthogonal design matrix of L₁₆ (4³). Based on the results of former studies, we further determined the optimal number of green and violet LEDs. The results showed that: 1) G. molesta strongly preferred the green, violet, and blue LEDs; 2) G. molesta significantly preferred light at 405 nm, followed by 540 nm, and showed no phototaxis to 480 nm; 3) for the polychromatic light configuration, violet and green were the factors that determined the preference of G. molesta, and the lamp with 12 violet LEDs captured the most moths; and 4) for the lamps with different light intensities, 36 violet LEDs or 12 green LEDs attracted the most moths, with the former performing better.

Several rare and common monosaccharides were screened for toxic effects on the Formosan subterranean termite, Coptotermes formosanus Shiraki, with the aim of identifying environmentally friendly termiticides. myo-inositol and phytic acid, which are nontoxic to mammals, were identified as potential termite control compounds. Feeding bioassays with termite workers, where both compounds were supplied on filter paper in concentrations from 160.2 to 1,281.7 µg/ mm³, showed concentration-dependent toxicity within 2 wk. Interestingly myo-inositol was nontoxic when administered to termites in agar (40 mg/ml) in the absence of a cellulosic food source, an unexplained phenomenon. In addition, decreased populations of termite hindgut protozoa were observed upon feeding on myo-inositol but not phytate-spiked filter paper. Radiotracer feeding studies using myo-nositol[2-³H] with worker termites showed no metabolism after ingestion over a 2-d feeding period, ruling out metabolites responsible for the selective toxicity.

The body of pesticide research on spiders is sparse with most studies using topical or residual applications to assess efficacy. Data on the effects of fumigation on spider survivorship are scarce in the scientific literature. In this study, we exposed adult male and female brown recluse spiders, Loxosceles reclusa Gertsch & Mulaik, and female brown widow spiders, Latrodectus geometricus C. L. Koch, to a commercial fumigation event using sulfuryl fluoride directed at termite control. General consensus from the pest control industry is that fumigation is not always effective for control of spiders for a variety of reasons, including insufficient fumigant dosage, particularly, for contents of egg sacs that require a higher fumigant dosage for control. We demonstrated that a sulfuryl fluoride fumigation with an accumulated dosage of 162 oz-h per 1,000 ft³ at 21°C over 25 h (≈1.7× the drywood termite dosage) directed at termites was sufficient to kill adult brown recluse and brown widow spiders. The effectiveness of commercial fumigation practices to control spiders, and particularly their egg sacs, warrants further study.

Isoline pairs of hybrid corn, similar except for presence or absence of a Bt trait, were planted at eight sites across Alabama over three years. This study evaluated insect damage, yield, and aflatoxin levels as affected by the Bt traits, YieldGard Corn Borer (expressing Cry1Ab), Herculex I (expressing Cry1F), Genuity VT Triple PRO (expressing Cry1A.105 and Cry2Ab2), Agrisure Viptera 3111 (expressing Vip3Aa20 and Cry1Ab), and Genuity SmartStax (expressing Cry1A.105, Cry2Ab2, and Cry1F). When examined over all sites and years, hybrids with any of the included Bt traits had lower insect damage and higher yields. However, insect damage was not consistently correlated to yield. Bt traits expressing multiple proteins provided greater protection from corn earworm feeding than did traits for single proteins. Yields and aflatoxin levels were highly variable among sites although irrigated sites had higher yields than nonirrigated sites. Aflatoxins commonly accumulate in corn in the southeastern United States because of prevailing high temperatures and frequent dry conditions. Aflatoxin levels were not consistently associated with any factors that were evaluated, including Bt traits.

Asiatic rice borer, Chilo suppressalis (Walker), larvae cause extensive crop losses worldwide. Because chemical control is problematic, and sex pheromone applications are a valuable management tactic in China, judicious timing of a minimal density of pheromone dispensers is important in developing a cost-effective C. suppressalis IPM program. During June–October in 2011, 20, 30, 40, and 50 dispensers per hectare for mass trapping, and 200, 300, 400, and 500 dispensers per hectare for mating disruption were placed in northeastern China rice fields. Based on those results, only the two highest mass trapping densities were used in 2012–2013. The 40, 50, and 500 dispenser densities reduced egg masses to <2.0 per 100 tillers, compared with >9.5 in the insecticide-treated plots in 2011–2013. The reduced oviposition resulted in >85% reduction of larval damage, which was comparable with the currently used insecticides, dimethoate and deltamethrin (0.35 kg/ha), which gave no egg reduction, but ≈80 and 89% reduction in larval damage. The 40 and 500 densities are recommended to Chinese rice farmers for mass trapping and mating disruption programs, respectively.

Brown marmorated stink bug, Halyomorpha halys (Stål), injury to late-season apple cultivars was measured at harvest in 2011 and 2012 in commercial orchards in four mid-Atlantic states. In each orchard block, a border zone (adjacent to woods), an interior zone (near orchard center), and an intermediate zone (between border and interior zones) comprised 1–3 tree rows per zone, depending on block size. Just before commercial harvest, 10 fruit were sampled from the upper, middle, and lower third of the canopy from five trees in each zone. After 3–5 wk in cold storage, fruit were examined for external and internal injury, and severity of internal injury (number of injury sites per fruit) from H. halys. A zero-inflated negative binomial model accounted for significant variation among the orchards and showed that apples from the upper canopy of border zone trees had the highest probability of experiencing external and internal injury. A minor interaction was detected among the orchards and zones for injury prevalence and severity, but there was no evidence of an orchard showing less expected injury in the border zone compared with other zones. Adjusting for orchard-to-orchard variation, differences in injury distributions among the zones and canopies were primarily due to injury prevalence rather than expected injury severity. The implications of these results to scouting and managing H. halys in eastern apple orchards are discussed.

Use of early ripening highbush blueberry cultivars to avoid infestation and mass trapping were evaluated for managing spotted wing drosophila, Drosophila suzukii (Matsumura). Fourteen highbush blueberry cultivars were sampled for spotted wing drosophila infestation. Most ‘Earliblue’, ‘Bluetta’, and ‘Collins’ fruit were harvested before spotted wing drosophila oviposition commenced, and so escaped injury. Most fruit from ‘Bluejay’, ‘Blueray’, and ‘Bluehaven’ were also harvested before the first week of August, after which spotted wing drosophila activity led to high levels of blueberry infestation. In a separate experiment, damage to cultivars was related to the week in which fruit were harvested, with greater damage to fruit observed as the season progressed. Attractant traps placed within blueberry bushes increased nearby berry infestation by 5%, irrespective of cultivar and harvest date. The significant linear reduction in infestation with increasing distance from the attractant trap suggests that traps are influencing fly behavior to at least 5.5 m. Insecticides applied to the exterior of traps, compared with untreated traps, revealed that only 10–30% of flies visiting traps enter the traps and drown. Low trap efficiency may jeopardize surrounding fruits by increasing local spotted wing drosophila activity. To protect crops, traps for mass trapping should be placed in a perimeter outside fruit fields and insecticides need to be applied to the surface of traps or on nearby fruit to function as an attract-and-kill strategy.

Halyomorpha halys Stål, the brown marmorated stink bug (Hemiptera: Pentatomidae), is an invasive pest with established populations in Oregon. The generalist feeding habits of H. halys suggest it has the potential to be a pest of many specialty crops grown in Oregon, including hazelnuts, Corylus avellana L. The objectives of this study were to: 1) characterize the damage to developing hazelnut kernels resulting from feeding by H. halys adults, 2) determine how the timing of feeding during kernel development influences damage to kernels, and 3) determine if hazelnut shell thickness has an effect on feeding frequency on kernels. Adult brown marmorated stink bugs were allowed to feed on developing nuts for 1-wk periods from initial kernel development (spring) until harvest (fall). Developing nuts not exposed to feeding by H. halys served as a control treatment. The degree of damage and diagnostic symptoms corresponded with the hazelnut kernels' physiological development. Our results demonstrated that when H. halys fed on hazelnuts before kernel expansion, development of the kernels could cease, resulting in empty shells. When stink bugs fed during kernel expansion, kernels appeared malformed. When stink bugs fed on mature nuts the kernels exhibited corky, necrotic areas. Although significant differences in shell thickness were observed among the cultivars, no significant differences occurred in the proportions of damaged kernels based on field tests and laboratory choice tests. The results of these studies demonstrated that commercial hazelnuts are susceptible to damage caused by the feeding of H. halys throughout the entire period of kernel development.

Taro (Colocasia esculenta (L.) Schott) plays a prominent role in the economies and cultures of Pacific Island countries such as Fiji. Unfortunately, taro is highly susceptible to invasion from taro beetles, which burrow into the corms and weaken the plants, rendering them unmarkable and prone to rot. Papuana uninodis Prell, an invasive alien species that is native to the Solomon Islands and Vanuatu, was first reported on Viti Levu (Fiji's largest island) in 1984. Since that time, taro production on Viti Levu has fallen substantially. In this paper, we employ data from surveys of households and communities to document the impacts of P. uninodis on Viti Levu. We then identify three management approaches—chemical controls, cultural controls, and switching from taro to another staple crop—and conduct a cost—benefit analysis of each. We find strong arguments for pursuing chemical control, which derives a net present value of monetised benefits of about FJ$139,500 per hectare over 50 yr, or >FJ$21 for each FJ$1 spent. Still, any of the three management options is more efficient than no management, even without any attempt to quantify the benefits to biodiversity or forest protection, underscoring the value of actively managing this invasive alien species.

Intrinsic toxicities of chlorantraniliprole, fipronil, and imidacloprid were evaluated with topical applications on worker termites. Worker termites were exposed to substrates treated with formulated chlorantraniliprole to study contact toxicity, tunneling, and postexposure behaviors. The intrinsic toxicities (LD₅₀, ng/termite) of chlorantraniliprole (1.25, 0.96, and 0.44) and fipronil (0.12, 0.11, and 0.13) at 11 d were similar for workers from three termite colonies. Imidacloprid toxicity (LD₅₀) values were highly variable among the workers from three different colonies, values at 11 d ranging from 0.7 to 75 ng/termite. Termite workers exposed to sand and soils treated with chlorantraniliprole at 50 ppm exhibited delayed mortality and, for most of the exposure times, it took >5 d to observe 90–100% mortality in termite workers. Exposure to chlorantraniliprole-treated sand (50 ppm) for as little as 1 min stopped feeding and killed 90–100% of the workers. Tunneling (≈ 2 h) in different soil types treated with chlorantraniliprole at 50 ppm, even those with high organic matter (6.3%) and clay content (30%), caused immediate feeding cessation in worker termites and mortality in the next 7–14 d. Worker termites exposed for 1 and 60 min to sand treated with chlorantraniliprole (50 ppm) were able to walk normally for 4 h after exposure in most cases. Delayed toxicity, increased aggregation, and grooming were observed in exposed termites and discussed in the context of horizontal transfer effects within termite colonies.

The desert subterranean termite, Heterotermes aureus (Snyder), is the predominant termite of economic importance in the arid southwest. Chlorantraniliprole, a relatively new nonrepellent, slow acting termiticide has been shown to be capable of being transferred among colony members through social interactions, and thus may be effective beyond its original site of application. Using field grids, we evaluated the colony-level effects of chlorantraniliprole on H. aureus foraging activity. Repeated laboratory soil bioassays at 3, 15, 27 and 39 mo postapplication were performed to determine the effects of chlorantraniliprole on termite mortality and tunneling activity. Additionally, field tests of chlorantraniliprole were completed on 10 structures infested with H. aureus. In the experimental grids, the zone surrounded by a chlorantraniliprole perimeter was the only section in which a significant decrease in the number of termites collected occurred, but this was observed in both treatment and controls plots. Overall, no significant colony-level effects of chlorantraniliprole application were observed within the grids. Laboratory bioassays resulted in high mortality and significantly lower tunneling activity of exposed termites at all time points. In structures, the initial application of chlorantraniliprole was sufficient to control infestations in 6 out of 10 cases without supplemental applications. Additional treatments were confined to areas that had not been treated previously. Results show that chlorantraniliprole is capable of achieving control of desert subterranean termites under most conditions. This is likely a result of its high toxicity instead of colony-level effects resulting from termiticide transfer.

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide crop pest. The resistance to commonly applied acaricides (in this report, “acaricide” refers to both acaricides and insecticides that are toxic to mites) has seriously impaired T. urticae control in the field. Here, the sensitivity of eggs, larvae, and adults of laboratory and field populations of T. urticae to various acaricides was investigated. Based on data obtained with an acaricide-sensitive laboratory strain collected in 2009, abamectin was the most toxic of the tested acaricides. For each acaricide, susceptibility was greatest for larvae, least for adults, and intermediate for eggs. The egg was the most sensitive stage to abamectin, bifenazate, and hexythiazox; the larva was the most sensitive stage to abamectin, hexythiazox, bifenazate, propargite, and chlorfenapyr; and the adult was the most sensitive stage to abamectin, bifenazate, and chlorfenapyr. Based on the results obtained with the acaricide-sensitive laboratory strain, acaricides were selected to test against eggs, larvae, and adults of four field populations of T. urticae from Beijing, China. Although the field populations differed in their resistance to the acaricides in laboratory bioassays, the eggs, larvae, and adults of the four populations were sensitive to bifenazate and highly resistant to abamectin. Field trials for control of T. urticae in Beijing, China, should be conducted with bifenazate and other acaricides rather than with abamectin.

The vegetable leafminer, Liriomyza sativae Blanchard, is a key pest of vegetable and ornamental crops worldwide and is mainly controlled by insecticides. The toxicity of fenpropathrin on adult flies of F1 generation of six Iranian populations of the pest was assessed using the residual glass vial method. The bioassay results showed significant differences in susceptibility to fenpropathrin among the populations tested. Resistance ratios ranged from 5.09 to 28.32. The resistant populations were reared in the greenhouse under fenpropathrin pressure for 14 mo and then susceptibility of both larvae and adults of these strains to fenpropathrin was evaluated. The resistance levels significantly increased in these populations. Further study demonstrated that diethyl maleate and triphenyl phosphate had no synergistic effects on fenpropathrin, however, this compound was significantly synergized by piperonyl butoxide in all tested populations. S,S,S-tributyl phosphorotrithioate also showed a slight synergism with fenpropathrin. Enzyme assays for general esterases, glutathione S-transferases and monooxygenases were performed on adults and larvae of L. sativae. The activity of glutathione s-transferase in different resistant and susceptible strains was not significantly different. The activity of esterases in resistant strains was higher than the susceptible strain. Monooxygenase levels also were higher in resistant strains compared with the susceptible strain. Synergism and biochemical assays revealed that esterases and monooxygenases have a major role in resistance of L. sativae to fenpropathrin.

The whitebacked planthopper, Sogatella furcifera (Horváth), and small brown planthopper, Laodelphax striatellus (Fallén), both are important crop pests throughout China, especially in rice. Application of chemical insecticides is the major control practice. Consequently, insecticide resistance has become an urgent issue. In this study, resistance levels to six conventional insecticides were evaluated for these two species collected from major occurring areas of China. Additionally, imidacloprid- (resistance ratio [RR] = 10.4-fold) and buprofezin (RR = 15.1-fold)-resistant strains of whitebacked planthopper were obtained through laboratory selections for cross-resistance profiling and synergism assessment to understand resistance mechanisms. The results showed that all tested populations of both species exhibited low to high levels of resistance to chlorpyrifos, while remaining susceptible to thiamethoxam. Three of the 14 whitebacked planthopper populations showed low to moderate resistance to imidacloprid, while all small brown planthopper populations reminded susceptible. All small brown planthopper and whitebacked planthopper (except one) populations showed at least moderate resistance (RR = 10.1–271.1) to buprofezin. All small brown planthopper populations remained susceptible to pymetrozine and nitenpyram, and all whitebacked planthopper populations remained susceptible to isoprocarb. The imidacloprid-resistant whitebacked planthopper strain showed no significant cross-resistance to other tested insecticides. However, the buprofezin-resistant strain exhibited a low-level cross-resistance (CR = 3.1) to imidacloprid. Piperonyl butoxide, triphenyl phosphate, and diethylmaleate displayed no synergism effect on the resistant whitebacked planthopper strains.

Since 2004–2005 cotton expressing Cry1Ac and Cry2Ab insecticidal proteins from the bacterium Bacillus thuringiensis has been commercially available in Australia to manage the target pests Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren). In both target species, the frequency of alleles conferring resistance to Cry2Ab is unexpectedly high in field populations. A significant challenge for managing these pests would occur if resistance to Cry2Ab toxins inadvertently selected for resistance to other insecticides used to control them. Dose-response bioassays were performed to measure the toxicity of currently registered insecticide sprays on isogenic strains of Cry2Ab-resistant and Cry2Ab-susceptible H. armigera and H. punctigera. Within-species comparisons of Cry2Ab-resistant and Cry2Ab-susceptible strains of H. armigera and H. punctigera indicate no cross-resistance with pyrethroid insecticides. Additionally, Cry2Ab-resistant strains were not cross-resistant to the following selective insecticides: indoxacarb, chlorantraniliprole, and avermectins. In both H. armigera and H. punctigera, Cry2Ab-resistant colonies exhibited a small, but significant, degree of enhanced susceptibility in response to chlorpyrifos and methomyl. We report higher tolerance to conventional insecticides in H. armigera compared with H. punctigera. Our results indicate that there is no significant interplay between Cry2Ab resistance frequencies in H. armigera and H. punctigera and frequencies of resistance to a range of insecticide sprays currently registered for cotton. Therefore, we conclude that any increases in frequencies of the common Cry2Ab resistance phenotypes identified in Australian populations of Helicoverpa spp. are unlikely to increase resistance risk for the indoxacarb, chlorantraniliprole, or avermectin classes of insecticide.

During oviposition, female Sirex noctilio (F.) (Siricidae) woodwasps inject their conifer hosts with a venom gland secretion. The secretion induces a variety of host physiological changes that facilitate subsequent lethal infection by a symbiotic fungus. A heat-stable factor that can migrate from the site of oviposition in the trunk through the xylem to needles in the crown of attacked pines was purified by size-fractionation and reversed-phase—high-performance liquid chromatography using activity assays based on defense gene induction as well as the needle wilt response in pine shoot explants. An 11-amino acid, posttranslationally modified peptide (SEGPROGTKRP) encoded by the most abundant transcript recovered from S. noctilio venom gland tissue comprised the backbone of the 1,850 Da active factor. Posttranslational modifications included hydroxylation of a Pro residue at position 6 as well as O-glycosylation of Ser and Thr residues at positions 1 and 8, respectively. The O-linked sugars were identical α-linked N-acetylgalactosamine residues modified at the C6 position by addition of phosphoethanolamine. In contrast to the native peptide, a synthetic version of the hydroxylated peptide backbone lacking the glycosyl side chains failed to induce pine defense genes or cause needle wilt in excised shoots. This peptide, hereafter called noctilisin, is related to the O-glycosylated short-chain proline-rich antimicrobial peptides exemplified by drosocin. The noctilisin structure contains motifs which may explain how it avoids detection by pine defense systems.

Population genetic diversity of the oriental fruit fly, Bactrocera dorsalis (Hendel), on the Hawaiian islands of Oahu, Maui, Kauai, and Hawaii (the Big Island) was estimated using DNA sequences of the mitochondrial cytochrome c oxidase subunit I gene. In total, 932 flies representing 36 sampled sites across the four islands were sequenced for a 1,500-bp fragment of the gene named the C1500 marker. Genetic variation was low on the Hawaiian Islands with >96% of flies having just two haplotypes: C1500-Haplotype 1 (63.2%) or C1500-Haplotype 2 (33.3%). The other 33 flies (3.5%) had haplotypes similar to the two dominant haplotypes. No population structure was detected among the islands or within islands. The two haplotypes were present at similar frequencies at each sample site, suggesting that flies on the various islands can be considered one population. Comparison of the Hawaiian data set to DNA sequences of 165 flies from outbreaks in California between 2006 and 2012 indicates that a single-source introduction pathway of Hawaiian origin cannot explain many of the flies in California. Hawaii, however, could not be excluded as a maternal source for 69 flies. There was no clear geographic association for Hawaiian or non-Hawaiian haplotypes in the Bay Area or Los Angeles Basin over time. This suggests that California experienced multiple, independent introductions from different sources.

Liriomyza huidobrensis (Blanchard) is a highly destructive invasive leafminer pest currently causing extensive damage to vegetable and horticultural crops around the world. Liriomyza langei Frick is a leafminer pest native to California that cannot currently be morphologically distinguished from L. huidobrensis. We used a DNA-barcoding approach, a published PCR-RFLP method, and a new multiplex PCR method to analyze 664 flies matching the morphological description of huidobrensis—langei. We found no evidence for the presence of L. huidobrensis in our extensive samples from California. In addition to the new molecular method, this work is important because it provides definitive data that the California “pea leafminer” is currently, and has probably always been, L. langei. These data will also be important in the event that the highly invasive L. huidobrensis ever becomes established.

Wild Mediterranean fruit fly specimens collected from various regions worldwide were screened for the glycine to alanine (Gly->Ala) point mutation (G328A) in the acetylcholinesterase enzyme, presumably causing resistance to organophosphates. We found that the single nucleotide polymorphism (SNP) responsible for this amino acid change is located at the beginning of exon 6 of the Ccace2 gene. The identification of the exact location of the SNP permitted PCR primer design around this site and direct sequencing of the corresponding genomic region. We detected the resistance allele in natural Mediterranean fruit fly populations from Brazil and Spain, but not from other sites in four continents. The known treatment history of sites suggests that the resistance buildup is linked to organophosphate application in the field. The PCR-based detection provides a screening method useful for monitoring Mediterranean fruit fly insecticide resistance in local populations and improving pest management strategies accordingly.

The Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), is an important pest in the western Great Plains of the United States, where it causes hundreds of millions of dollars of losses to barley and wheat production through reduced yields. Experiments to evaluate the effect of early planting and resistance in barley (Hordeum vulgare L.) on D. noxia were conducted at Fort Collins, CO; Tribune, KS; and Sidney, NE, in 2007, 2008, and 2009. Treatments included two planting dates and four cultivars, the D. noxia-resistant barley cultivars ‘Stoneham’ (Otis*4/STARS 9577B) and ‘Sidney’ (Otis*4/STARS 9301B), the susceptible cultivar ‘Otis’, and Otis treated with thiamethoxam. In tiller samples collected from May through early July, consistently lower D. noxia populations were found in plots planted ≈30 d earlier than normal at Fort Collins in all three years, and at Tribune in 2007. With one location-year exception, lower D. noxia populations occurred on plants of resistant varieties or the susceptible variety Otis treated with thiamethoxam than on untreated Otis plants. There were no significant differences in D. noxia populations produced on plants of either resistant variety and susceptible Otis plants treated with thiamethoxam. Interactions between resistant varieties and early planting resulted in reduced D. noxia populations at Fort Collins in 2007 and 2009, and at Tribune and Sidney in 2007. Planting D. noxia-resistant barley varieties, planting varieties earlier than normal, and the synergistic effect of resistant variety and early planting can significantly reduce D. noxia infestations on barley in the western High Plains.

The English grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae), is a common worldwide pest of wheat (Triticum aestivum L.). The use of improved resistant cultivars by the farmers is the most effective and environmentally friendly method to control this aphid in the field. The winter wheat genotypes 98-10-35 and Amigo are resistant to S. avenae. To identify genes responsible for resistance to S. avenae in these genotypes, differential-display reverse transcription-polymerase chain reaction was used to identify the corresponding differentially expressed sequences in current study. Two backcross progenies were obtained by crossing the two resistant genotypes with the susceptible genotype 1376. Six potential expected-differential bands were sequenced. Lengths of the expressed sequence tags ranged from 128 to 532 bp. Although these expressed sequences were likely associated with S. avenae resistance, there was one expressed sequence tag located on 7DL chromosome, and its potential function may associate with the ability to maintain photosynthesis in wheat. That serves as an active way for tolerant common wheat with resistant to S. avenae. Cloning the full length of these sequences would help us thoroughly understand the mechanism of wheat resistance to S. avenae and be valuable for breeding cultivars with S. avenae resistance.

Changes in protein content, peroxidase activity, and isozyme profiles in response to soybean aphid feeding were documented at V1 (fully developed leaves at unifoliate node, first trifoliate leaf unrolled) and V3 (fully developed leaf at second trifoliate node, third trifoliate leaf unrolled) stages of soybean aphid-tolerant (KS4202) and -susceptible (SD76R) soybeans. Protein content was similar between infested and control V1 and V3 stage plants for both KS4202 and SD76R at 6, 16, and 22 d after aphid introduction. Enzyme kinetics studies documented that control and aphid-infested KS4202 V1 stage and SD76R V1 and V3 stages had similar levels of peroxidase activity at the three time points evaluated. In contrast, KS4202 aphid-infested plants at the V3 stage had significantly higher peroxidase activity levels than control plants at 6 and 22 d after aphid introduction. The differences in peroxidase activity observed between infested and control V3 stage KS4202 plants at these two time points suggest that peroxidases may be playing multiple roles in the tolerant plant. Native gels stained for peroxidase were able to detect differences in the isozyme profiles of aphidinfested and control plants for both KS4202 and SD76R.

In total, 339 faba bean (Vicia faba L.) and 100 pea (Pisum sativum L.) accessions were screened for their ability to resist Callosobruchus chinensis L. in free choice laboratory tests. Four, 15, and 43 faba bean varieties were highly resistant, resistant, and moderately resistant to C. chinensis, respectively. Three immune, three highly resistant, and six resistant accessions were discovered among the pea germplasm. The faba bean and pea varieties presented a hundred-kernel weight reduction varied from 0.18 to 35.36% for faba bean varieties and 0 to 56.53% for pea varieties. Varieties with brown and black seed color had significantly fewer wormholes and higher C. chinensis resistance than varieties with light-color seeds. Resistance to C. chinensis showed a significant, positive correlation with catechin, total polyphenol, and γ-aminobutyric acid contents, but a significant, negative correlation with oligosaccharide content. Correlation coefficients (r) between infestation rate of faba bean and total phenol, catechin, and oligosaccharide contents were —0.9723, —0.8071, and 0.7631, respectively. The values of r for pea resistance and total phenol, catechin, and oligosaccharide content were —0.8846, —0.7666, and 0.8308, respectively. The results suggest that quality components in faba bean and pea have a great role in resistance against C. chinensis.

Heat stress exerts significant impact on plant—parasite interactions. Phytohormones, such as salicylic acid (SA), play important roles in plant defense against parasite attacks. Here, we studied the impact of a combination of heat stress and exogenous SA on the resistance of wheat (Triticum aestivum L.) plants to the Hessian fly [Mayetiola destructor (Say) ]. We found that the wheat cultivar ‘Molly’, which contains the resistance gene H13, lost resistance to Hessian fly under heat stress (40°C for 3 and 6 h), and that exogenous application of SA on Molly seedlings right before heat stress can partially prevent the loss of resistance of Molly plants under heat conditions. Our findings have significant implications for understanding the dynamics of plant—insect interactions in the context of heat stress.