The number of larval instars varies widely across insect species. Although instar number is frequently considered to be invariable within species, intraspecific variability in the number of instars is not an exceptional phenomenon. However, the knowledge has remained fragmentary, and there are no recent attempts to synthesize the results of relevant studies. Based on published case studies, we show that intraspecific variability in the number of larval instars is widespread across insect taxa, occurring in most major orders, in both hemimetabolous and holometabolous insects. We give an overview of various factors that have been observed to affect the number of instars. Temperature, photoperiod, food quality and quantity, humidity, rearing density, physical condition, inheritance, and sex are the most common factors influencing the number of instars. We discuss adaptive scenarios that may provide ultimate explanations for the plasticity in instar number. The data available largely support the compensation scenario, according to which instar number increases in adverse conditions when larvae fail to reach a species-specific threshold size for metamorphosis. However, in Orthoptera and Coleoptera, there are some exceptional species in which instar number is higher in favorable conditions. In more specific cases, the adaptive value of the variability in instar number may be in reaching or maintaining the developmental stage adapted to hibernation, producing additional generations in multivoltine species, or increasing the probability of surviving in long-lasting adverse conditions.

Mixed viral infections of heterologous viruses such as Potato virus Y (familyPotyviridae, genusPotyvirus, PVY) and Potato leafroll virus (familyLuteoviridae, genusPolerovirus, PLRV) are a regular occurrence in Idaho’s potato,Solanum tuberosum (L.), cropping systems. An increased number of plant samples from Idaho’s potato fields over the past 2 yr has serologically tested positive for both PVY and PLRV via double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and exhibited more severe symptoms than singly-infected plants (PVY or PLRV). Several studies have extensively examined the mixed infection phenomenon but to the best of our knowledge, none have examined the effect of such infections on vector biology and preference. Laboratory studies were conducted to examine the effect of mixed viral (PVY–PLRV) infection on the fecundity and preference of two of the most efficient PVY and PLRV vectors, the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae).M.persicae andM.euphorbiae adults were clip-caged (one adult per cage) to leaflets of PVY, PLRV, PVY–PLRV-infected, and noninfected potato plants. The number of nymphs produced in all four treatments was recorded after 96 h.M.persicae andM.euphorbiae fecundity was significantly higher on mixed infected plants than on singly infected plants or noninfected plants. Preference of alatae and apterae ofM.persicae andM.euphorbiae was determined with the use of settling bioassays. Both alatae and apterae ofM.persicae andM.euphorbiae preferentially settled on PVY–PLRV-infected plants than on singly infected plants (PVY or PLRV) or noninfected plants.

A new defect of potato,Solanum tuberosum L., “zebra chip,” so named for the characteristic symptoms that develop in fried chips from infected potato tubers, has recently been documented in several southwestern states of the United States, in Mexico, and in Central America. This defect is causing millions of dollars in losses to both potato producers and processors. Zebra chip plant symptoms resemble those caused by potato purple top and psyllid yellows diseases. Experiments were conducted to elucidate the association between the psyllidBactericera cockerelli (Sulc) (Homoptera: Psyllidae) and zebra chip by exposing clean potato plants to this insect under greenhouse and field conditions. Potato plants and tubers exhibiting zebra chip symptoms were tested for phytoplasmas by polymerase chain reaction. Potato psyllids collected from infected potato fields also were tested. Results indicated that there was an association between the potato psyllid and zebra chip. Plants exposed to psyllids in the greenhouse and field developed zebra chip. In the greenhouse, 25.8 and 59.2% of tubers exhibited zebra chip symptoms in the raw tubers and fried chips, respectively. In the field, 15 and 57% of tubers showed symptoms in raw tubers and chips, respectively. No zebra chip was observed in tubers from plants that had not been exposed to psyllids, either in the greenhouse or field. No phytoplasmas were detected from potato plants or tubers with zebra chip symptoms, suggesting that these pathogens are not involved in zebra chip. Of the 47 samples of potato psyllids tested, only two tested positive for the Columbia Basin potato purple top phytoplasma.

The biology ofCirrospilus coachellae Gates (Hymenoptera: Eulophidae), an ectoparasitoid of the larvae ofMarmara gulosa Guillén & Davis (Lepidoptera: Gracillariidae) was studied in the laboratory. In total, 120.3 ± 21.2 adults were produced per female at 26°C. Females survived an average of 23.5 ± 4.4 d and parasitized an average of 49.8 ± 10.2 hosts over their lifetime.C.coachellae is a facultatively gregarious parasitoid with up to eight parasitoids developing per host with an average of 2.5 ± 0.1 in the laboratory. A female-biased sex ratio of 0.31 (male/total) was exhibited. Development times decreased with increasing temperatures from 23.7 ± 0.2 d at 20°C to 9.2 ± 0.1 at 29°C. Estimated lower and upper development thresholds were 14.1 and 36.7°C, respectively. Maximal development rate occurred at 31.3°C, and 138 degree-days was required to complete the cycle.

Oriental fruit fly,Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), was discovered on Tahiti Island in July 1996. Eradication programs were conducted from 1997 to 2001, but failed. From 1998 to 2006,B.dorsalis was recovered from 29 different host fruit from the five Society Islands: Tahiti, Moorea, Raiatea, Tahaa, and Huahine. Analysis of coinfestation patterns byB.dorsalis,Bactrocera tryoni (Froggatt), andBactrocera kirki (Froggatt) suggestedB.dorsalis had displaced these two species and become the most abundant fruit fly in coastal areas. To suppressB.dorsalis populations, a classical biological control program was initiated to introduce the natural enemyFopius arisanus (Sonan) (Hymenoptera: Braconidae) into French Polynesia from Hawaii. Wasps were released and established on Tahiti, Moorea, Raiatea, Tahaa, and Huahine Islands. In guava,Psidium guajava L., collections for Tahiti,F.arisanus parasitism of fruit flies was 2.1, 31.8, 37.5, and 51.9% for fruit collected for 2003, 2004, 2005 and 2006, respectively. Based on guava collections in 2002 (before releases) and 2006 (after releases), there was a subsequent decrease in numbers ofB.dorsalis,B.tryoni, andB.kirki fruit flies emerging (per kilogram of fruit) by 75.6, 79.3, and 97.9%, respectively. These increases inF.arisanus parasitism and decreases in infestation were similar for other host fruit. Establishment ofF.arisanus is the most successful example of classical biological control of fruit flies in the Pacific area outside of Hawaii and serves as a model for introduction into South America, Africa, and China where species of theB.dorsalis complex are established.

Diabrotica spp. (Coleoptera: Chrysomelidae) beetles and southern green stink bugs,Nezara viridula (L.) (Heteroptera: Pentatomidae), are pests on corn,Zea mays L., and soybean,Glycine max (L.) Merr., as well as on cucurbits. Control of these insects has depended on chemicals. An alternative to chemical control is the use of biologicals. Use of bacteria, fungi, viruses, pheromones, and metabolites to control these insects can potentially improve resistance management and reduce pesticide use. Other thanBacillus thuringiensis Berliner, few bacteria have been discovered that are lethal to either of these pests.Chromobacterium subtsugae Martin et al., a newly described bacterium that is known to be toxic to Colorado potato beetle,Leptinotarsa decemlineata (Say), larvae, was found to be toxic to both diabroticite adult beetles and southern green stink bug adults. In laboratory assays, toxins produced by these bacteria kill 80–100% of the adults of two species of diabroticite beetles,Diabrotica undecimpunctata howardi Barber andDiabrotica virgifera virgifera LeConte, and 100% of southern green stink bug adults within 6 d. For green stink bug, live bacteria were not needed for toxicity.

This study assessed the effects of refrigerated storage on the suitability of eggs of the glassy-winged sharpshooter,Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), as hosts for propagation of the parasitoidGonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). Development of the host eggs was terminated by chilling at 2°C for 5 d before storage was initiated at 10°C for up to 70 d. Parasitism, adult emergence rate, developmental time, and sex ratio were used to gauge the suitability of the eggs as hosts after storage. In addition to these measures, demographic growth parameters also were used to assess the quality of the wasp progeny through the F₂ generation. Host eggs stored 20 d remained fully acceptable to the wasps for attack. Although the parasitism rate decreased with storage time, > 80% adult parasitoid emergence was realized from eggs stored 30 d. After 70 d storage, adult emergence rate was decreased by 48%, fecundity decreased by 53%, female production by 19%, developmental time was extended 3 d, and female longevity was shortened 5 d. The emergence pattern of F₁ but not F₂ adults varied with storage time of the parental and grandparental hosts, respectively. For the F₂ generation, emergence rate, development, and sex ratio did not vary with storage time when the F₁ parents parasitized fresh host eggs. Demographic parameters for the F₁ population showed that net reproductive rate was > 20 although it decreased significantly after their parental host eggs were stored for > 30 d. The intrinsic and finite rates of increase, population doubling time, and mean generation time decreased only after storage for 60 d. Our results show that short-term cold storage could be used for maintaining wasp populations in a mass-rearing program and that the detrimental effects of chilling host eggs in storage for over 30 d do not extend to F₂ generation.

Six mango,Mangifera indica L., plantations around Parakou, northern Benin, were sampled at 2-wk intervals for fruit fly damage from early April to late May in 2005. Mean damage ranged from 1 to 24% with a weaver ant,Oecophylla longinoda (Latreille), being either abundant or absent. The fruit fly complex is made up ofCeratitis spp. andBactrocera invadens Drew et al., a new invasive species in West Africa. In 2006,Ceratitis spp. peaked twice in the late dry season in early April and early May, whereasB.invadens populations quickly increased at the onset of the rains, from mid-May onward. Exclusion experiments conducted in 2006 with ‘Eldon’, ‘Kent’, and ‘Gouverneur’ confirmed that at high ant abundance levels,Oecophylla significantly reduced fruit fly infestation. Although fruit fly control methods are still at an experimental stage in this part of the world, farmers who tolerated weaver ants in their orchard were rewarded by significantly better fruit quality. Conservation biological control with predatory ants such asOecophylla in high-value tree crops has great potential for African and Asian farmers. Implications for international research for development at the Consultative Group on International Agricultural Research level are discussed.

(E,Z)-2,4-decadienoate (pear ester) is a larval kairomone for the codling moth,Cydia pomonella (L.) (Lepidoptera: Tortricidae). Orchard studies were conducted in 2005 and 2006 in apple,Malus domestica Borkhausen, and pear,Pyrus communis L., to evaluate a 5% active ingredient (AI), microencapsulated formulation of pear ester (PE-MEC) as an insecticidal additive for the codling moth granulovirus (CpGV). Although CpGV applied at 5–15-d intervals at commercial rates (2.2 × 10¹²–10¹³ granules per ha) killed the majority (82–94%) of larvae found inside infested fruit, it did not eliminate significant damage, i.e., 30–92% fruit injury at harvest versus 51–82% in controls. PE-MEC treatments had significant but inconsistent results in our tests. In apple (mixed cultivars), PE-MEC (3.7–4.7 g [AI]/ha) plus CpGV reduced the percentage of fruit injured during the second but not the first larval generation, compared with CpGV alone, but there no was no additional population reduction (live larvae collected from infested fruit and tree bands). In ‘Bartlett’ pear, PE-MEC (3.7 g [AI]/ha) plus CpGV significantly increased larval mortality and reduced deep fruit entries at harvest over CpGV alone in 2006, but similar improvements were not observed in 2005 when a lower rate (1.5 g [AI]/ha) was tested. Surprisingly, compared with untreated controls, the PE-MEC formulation alone also reduced fruit injury (mid-season in Bartlett) and larval survivorship inside infested fruit at harvest (2006 apple tests and both years in Bartlett). Although pear ester seems amenable as a kairomonal adjuvant for use with insecticides, our inconsistent data with CpGV in apple and pear suggest practical improvements in formulation and application strategies (e.g., to optimize and maintain attractive release rates) are needed.

From 2001 to 2004, field studies were conducted to evaluate the effect of the ecorational insecticides SpinTor (spinosad), BotaniGard (Beauveria bassiana), Neemix (azadirachtin), and Surround (kaolin) against crucifer flea beetle on canola,Brassica napus L., at the cotyledon stage. The ecorational treatments were compared with a standard foliar chemical insecticide, Capture (bifenthrin), and the chemical seed treatment insecticide Helix XTra (thiamethoxam). This study indicated that flea beetle injury was lower for Helix XTra, Capture, and the ecorational insecticide SpinTor. SpinTor was less effective when flea beetle populations were relatively high (200–300 per trap-week). Yields for chemical insecticide treatments were always greater than SpinTor, with differences being the smallest (68–374 kg/ha) at low levels of flea beetle feeding injury. Differences were greatest when canola seedling injury was high (775–1,364 kg/ha). Yield differences between the conventional insecticides and BotaniGard, Neemix, and Surround were 119–439 and 61–2,248 kg/ha at low and high flea beetle feeding injury, respectively. Although yield differences between SpinTor and chemical insecticides were relatively small at lower levels of flea beetle injury, net losses ranged from $47 to $151/ha when SpinTor was used as an alternative to a standard chemical seed treatment, Helix XTra. This suggests that SpinTor would not be a viable alternative to the chemical insecticide. Net losses ranged from $30 to $266/ha when BotaniGard, Neemix, and Surround were used as alternatives to the seed treatment.

Laboratory studies were conducted to develop ultralow oxygen (ULO) treatment for controlling western flower thrips,Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), on broccoli at a low temperature of 1°C. Complete control was achieved in 5 d at 0.003% oxygen. Oxygen level affected efficacy of ULO treatment. At a higher oxygen level of 0.03%, 6-d treatment killed ≈85% of thrips, and 10-d treatment killed all thrips. The 5-d ULO treatment with 0.003% oxygen was successfully tested on iced commercial broccoli of several cultivars without any noticeable negative effects on shelf-life and postharvest quality. The ULO treatment provided a safe and effective alternative to methyl bromide fumigation for postharvest control of western flower thrips on exported broccoli for industrial development.

Attraction of oriental fruit fly,Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), and nontarget insects to preservative fluids ethylene glycol antifreeze, propylene glycol antifreeze, or mineral oil in bucket traps that contained captured decaying male oriental fruit flies, a male lure (methyl eugenol), and a toxicant (DDVP vapor insecticidal strip) were compared with dry control traps. Significantly (P < 0.05) greater numbers ofB.dorsalis were captured in propylene glycol antifreeze traps than in other attractant trap types. Among attractant trap types with lowest negative impacts on nontarget insects, control traps captured significantly lower numbers of three species and one morphospecies of scavenger flies, one species of plant-feeding fly, and one species each of sweet- and lipid-feeding ants. Mineral oil traps captured significantly lower numbers of two species of scavengers flies and one morphospecies of plant-feeding fly, and one species of sweet-feeding ant. Because of the fragile nature of endemic Hawaiian insect fauna, the propylene glycol antifreeze bucket trap is best suited for use in environments (e.g., non-native habitats) where endemic species are known to be absent and mineral oil traps are more suited for minimizing insect captures in environmentally sensitive habitats.

We used the mark-and-recapture method in the field to test the effect of gamma radiation on the dispersal ability of the male sweetpotato weevil,Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), a serious sweetpotato pest in Japan. To evaluate the dispersal ability of male sweetpotato weevil, we released 27,218 males (13,302 males irradiated with a dose of 200 Gy and 13,916 nonirradiated males) in two replications (September and October 2005). Each replication lasted 5 d from the release of weevils to the removal of traps, and male weevils were released twice (1 and 3 d before trap setting). Forty pheromone traps were placed in lines corresponding to eight compass directions and five distance classes (20, 50, 100, 200, and 500 m) in each replication. We captured 2,263 irradiated males (17.0%) and 2,007 nonirradiated males (14.4%) in the two replications. Six irradiated and eight nonirradiated males were captured in the traps 500 m far from the release point. All parameters to evaluate the dispersal ability of irradiated male sweetpotato weevil (recapture rate, dispersal distance, and dispersal direction) were similar to nonirradiated males in three of the four trials. However, parameters were different between irradiated males and nonirradiated males in one trial. Because the majority of parameters consistently show that the similarity of the dispersal ability, we considered that male sweetpotato weevil irradiated with a dose of 200 Gy possessed equal dispersal ability to that of nonirradiated males in the field.

Pyramid traps, 2.44 m and 3.66 m in height, were compared with standard-sized pyramid traps, 1.22 m in height, to assess the impact of trap architecture on captures of adult plum curculio,Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), in two apple (Malus spp.) orchards and a blueberry (Vaccinium spp.) planting. The effects of adjacent habitat (organic orchard versus wooded areas), abiotic factors, and phenological stages of apple also were assessed to determine whether these variables influenced trap captures. Standard-sized pyramidal traps captured significantly more adults than larger trap variants. In the apple orchards, most adults (70–80%) were captured before petal fall with the exception of blocks adjacent to the organic orchard (25%). Significantly more adults were captured along the edge of an apple orchard (managed using an integrated pest management strategy) facing an organic apple orchard (76%) than along the edge facing wooded areas (24%). There was a significant positive correlation between daily trap captures and mean daily temperatures before petal fall in apple orchards.

The midgeDasineura mali (Kieffer) (Diptera: Cecidomyiidae) is a significant pest of apples (Malus spp.), and the recent identification of the female sex pheromone is enabling new direct control tactics to be considered. Direct control using male suppression will require knowledge of the frequency of multiple mating, dispersal and colonization rates, and the efficiency of male removal. Males were able to mate up to five times, with a mean of 2.7 times when presented in a 10 female-to-1 male group, designed to simulate male suppression. Male catch in response to the pheromone loading was curvilinear over 4 orders of magnitude from 3 μg to 30 mg on rubber septa. Trapping using a high-dose pheromone lure was combined with oil-based traps similar to the inexpensive New Zealand “Lynfield trap” used for tephritid surveillance, to test male suppression in young orchard blocks at 500 traps per ha. Monitoring traps indicated 96% lower catch in the treated plots compared with control plots, over 137 d. However, a lack of shoot tip infestation in both treated and untreated plots indicated limited colonization and prevented an assessment of potential population suppression. Furthermore, a contribution to these results from communication disruption cannot be ruled out. Replicated transects of frequency of infested shoots from a mature orchard across the adjacent young block confirmed that colonization by ovipositing females was essentially limited to the first 30 m.

To restore male mating competitiveness of Mexican fruit flies,Anastrepha ludens (Loew) (Diptera: Tephritidae), reared for sterile insect releases by the Mexican Fruit fly Eradication Campaign, two strain replacement techniques were evaluated. Field cage male competitiveness tests revealed that laboratory males of the Metapa strain mated 3 times less often with wild females than field-collected wild males. A strain developed from the cross of wild males and laboratory females (hybrid strain) was similar to a strain developed from the cross of laboratory males and females (laboratory strain) in that its females produced similar amounts of eggs and the eggs displayed similar levels of hatch and egg-to-pupa transformation in artificial diet. By contrast, a strain developed from the cross of wild males and females (wild strain), forced into artificial rearing, experienced a series of bottlenecks involving reduced egg laying and extremely poor development in diet. The male F1 progeny of the hybrid strain and field-collected wild males outcompeted F1 laboratory males in field cage tests for matings with field-collected wild females. In conclusion, we found that strains developed from the cross of wild males and laboratory females allowed us to restore male mating competitiveness of F1 Mexican fruit flies without compromising mass-rearing production.

Near-infrared spectroscopy (NIRS) was used to develop a simple and quick technique to differentiate two economically important species, the tobacco budworm,Heliothis virescens (F.), and corn earworm,Helicoverpa zea (Boddie), which are major pests of cotton,Gossypium hirsutum L., in the southern United States. In practice, it is difficult to distinguish the two species during their immature stages using morphological characteristics unless expensive microscopy equipment or trained technicians are available. The current studies demonstrated that the two species could be quickly and readily differentiated during early developmental stages, including egg and young larval (younger than third instar) stages, by using NIRS technology with up to 95% accuracy. NIRS technology could significantly improve pest diagnosis in cotton pest management.

We conducted a long-term investigation to ascertain effects on honey bee,Apis mellifera L., colonies during and after exposure to flowering canola,Brassica napus variety Hyola 420, grown from clothianidin-treated seed. Colonies were placed in the middle of 1-ha clothianidin seed-treated or control canola fields for 3 wk during bloom, and thereafter they were moved to a fall apiary. There were four treated and four control fields, and four colonies per field, giving 32 colonies total. Bee mortality, worker longevity, and brood development were regularly assessed in each colony for 130 d from initial exposure to canola. Samples of honey, beeswax, pollen, and nectar were regularly collected for 130 d, and the samples were analyzed for clothianidin residues by using high-performance liquid chromatography with tandem mass spectrometry detection. Overall, no differences in bee mortality, worker longevity, or brood development occurred between control and treatment groups throughout the study. Weight gains of and honey yields from colonies in treated fields were not significantly different from those in control fields. Although clothianidin residues were detected in honey, nectar, and pollen from colonies in clothianidin-treated fields, maximum concentrations detected were 8- to 22-fold below the reported no observable adverse effects concentration. Clothianidin residues were not detected in any beeswax sample. Assessment of overwintered colonies in spring found no differences in those originally exposed to treated or control canola. The results show that honey bee colonies will, in the long-term, be unaffected by exposure to clothianidin seed-treated canola.

Susceptibility to methoxyfenozide ofSpodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) larvae was determined through exposure of neonate and fourth instars to dipped and sprayed pepper,Capsicum annum L., leaves. Methoxyfenozide and spinosad were tested against adults of this noctuid by oral, residual, and topical application. In larvae, we evaluated five (range, 0.001–10 mg active ingredient [AI]/liter) and six (range, 1–250 mg [AI]/liter) concentration levels by instars, respectively, by using two application methods at three different age leaf residues (0, 3, and 6 d after application). According to LC₅₀ values, no significant differences were observed between the same age leaf residues of both application methods at 96 and 72 h after ingestion treatment on neonates and fourth instars, respectively. Nevertheless, toxicity of methoxyfenozide decreased significantly after time. For both application methods, the LC₅₀ values of the first leaf residue (0 d after application) were significantly lower than those of 6-d-old residues. Furthermore, larval weight of fourth instars fed for 48 h with pepper,Capsicum annum L., leaves containing methoxyfenozide was significantly suppressed. Spinosad and methoxyfenozide reduced in a dose-dependent manner the fecundity and fertility ofS. littoralis adults when treated oral and residually. Likewise, when methoxyfenozide was administered orally in three different adult crosses, the fecundity was strongly affected, independently of the treated sex. We conclude that the combination of lethal and sublethal effects of methoxyfenozide and spinosad might exhibit significant effects on the population dynamics ofS. littolaris.

The ability to manage insect pests in a site-specific manner is hindered by the costs and time required to describe pest densities and distributions. The purpose of this study was to determine whether insect pest distributions are related to site-specific management zones (SSMZs). Site-specific management zones, as described in this study, delineate fields into three zones of similar yield potential: high, medium, and low productivity. If insect densities vary across SSMZs, it is possible that management decisions could be made at the SSMZ level instead of treating the whole field. This research was conducted during summers 2001 and 2002 on cooperators’ farms in northeastern Colorado. Surveys were conducted within corn,Zea mays L., fields, so that densities of three common insect pests of Colorado corn could be compared across SSMZ. The three insect pests were western corn rootworm,Diabrotica virgifera virgifera LeConte; European corn borer,Ostrinia nubilalis (Hübner); and western bean cutworm,Richia albicosta (Smith).D.v.virgifera larvae and adults were most common in the high-productivity SSMZ.O.nubilalis larval abundance was similar at three fields, whereas in a fourth field the larvae were most common in the high-productivity SSMZ. In one field that contained substantial numbers ofR.albicosta, egg abundance was similar across SSMZs, whereas larvae were most common in the high-productivity SSMZ. Site-specific management zones seemed to correlate well with the abundance of some insect pests and might prove useful for managing insects in a site-specific manner.

Acoustic and traditional excavation methods were used in consecutive summers to conduct two geospatial surveys of distributions of white grubs and other soil invertebrates in two forage fields. Indicator variables were constructed from listener- and computer-based assessments of sounds detected at each recording site and then applied in geostatistical analysis, contingency analysis, and spatial analysis of distance indices (SADIE) of soil invertebrate distributions. Significant relationships were identified between the acoustic indicators and the counts of sound-producing soil invertebrates in a majority of the geostatistical and contingency analyses. Significant clusterings and overall spatial associations were identified also in most of the SADIE analyses. In addition, significant local spatial associations were identified between acoustic indicators and counts of sound-producing soil invertebrates that could be of potential value in selection of specific sites as targets for treatment or for untreated reserves in integrated pest management programs. An example is presented of the relative efficiency of acoustic surveys for targeting of white grub treatments.

Field experiments were conducted from 1972 to 1978 and from 1998 to 1999 to evaluate tobacco budworm,Heliothis virescens (F.) (Lepidoptera: Noctuidae), larval feeding on flue-cured tobacco,Nicotiana tabacum (L.), yield in eastern North Carolina. In the earlier studies, using variety Coker 319, treatment plots were evaluated when either 0 or 100% of plants in a plot were infested withH.virescens larvae. Treatment differences based on actual yield loss (kilograms per hectare) were compared with estimations of yield loss based on leaf consumption and leaf loss. Results indicate actual yield loss when 100% of plants were infested was less than the corresponding estimates of yield loss. In the later experiments, two tobacco budworm-resistant lines, ‘CU 263′ and ‘CU 370′, were compared with a commercial susceptible variety, K 326, when 0, 10, 20, or 40% of plants were infested (1998) and 0, 10, 40, 75, or 100% of plants were infested (1999). Although significant increases in leaf equivalents consumed were associated with infestations exceeding the recommended threshold, differences were not detected for yield (kilograms per hectare), quality (dollars per kilogram), and value (dollars per hectare) within each tobacco line. Additionally, there was not a significant correlation between value and infestations level for any of the tobacco lines. These results provide economic support for tolerance of a higher treatment threshold. Although K 326 sustained more leaf equivalent loss than CU 263 and CU 370, the value of K 326 harvested was higher than that of CU 263 and CU 370. To justify use of resistant varieties, the combination of pest pressure and the benefit of host plant resistance must be greater than the capacity of a susceptible variety to produce competitive yields, despite sustaining significantly higher loss.

To better understand the naturally occurring host range of Bean pod mottle virus (familyComoviridae, genusComovirus, BPMV) and its principal vectorCerotoma trifurcata (Förster) (Coleoptera: Chrysomelidae), 18 field-collected perennial plant species were tested for the presence of BPMV. By using no-choice assays, we determined the preference of these plants by bean leaf beetle, by measuring their level of herbivory relative to soybean,Glycine max (L.). New food hosts for adult bean leaf beetles includeLespedeza capitata (Michaux),Lotus corniculatus L.,Trifolium alexandrinum L.,Trifolium ambiguum Bieberstein, andTrifolium incarnatum L.Desmodium illinoense Gray is discovered as a new naturally occurring host for BPMV.

I report on the attraction of the white pine cone beetle,Conophthorus coniperda (Schwarz) (Coleoptera: Scolytidae), to traps baited with the host monoterpene limonene in western North Carolina. Both ( )- and (−)-limonene attracted male and female cone beetles to Japanese beetle traps in an eastern white pine,Pinus strobus L., seed orchard near Murphy, NC. Catches of cone beetles were directly proportional to the release rate of (−)-limonene; ( )-limonene was not tested for dose response. Attraction of cone beetles to the pheromone (±)-trans-pityol was increased significantly by both enantiomers of limonene. In all experiments, catches ofC. coniperda were strongly male biased with no treatment effect on sex ratio. (−)-Limonene had no effect on trap catches of the predatorEnoclerus nigripes (Say) to pityol, whereas ( )-limonene interrupted the attraction ofE. nigripes to traps baited with pityol. Of six monoterpenes commonly found in white pine cones, only (−)-α-pinene elicited attraction ofE. nigripes to Japanese beetle traps.

Field studies were conducted to investigate the effectiveness of yellow sticky traps as an alternative sampling technique for striped,Acalymma vittatum (F.), and spotted,Diabrotica undecimpunctata howardi Barber, cucumber beetles (Coleoptera: Chrysomelidae) and the diurnal beetle activity on muskmelon,Cucumis melo L., near Vincennes, IN, in 2003 and 2004. The experimental design included six replications of seven 20-m-long rows each of muskmelon with 1.5 m between rows. On each sampling date, two yellow sticky traps were placed randomly between rows in each replication. One sticky trap was placed vertically with the lower edge even with the top of the canopy, whereas the other trap was placed horizontally, even with the top of the canopy. After traps were placed in the field, number of beetles on plants was counted in situ from 0800 to 1600 hours at 2-h intervals the next day. After 48 h in the field, the number of cucumber beetles adhering on traps was counted. Analyses of variance and Tukey’s multiple comparison procedure were used to compare the densities of beetles among sampling times, and regression analyses were applied to correlate the numbers of beetles on traps and the numbers of in situ counts. Results show that both species of cucumber beetles were most active from 1200 to 1400 hours, and 20 beetles on the vertically positioned sticky trap were equivalent to one beetle per plant in the field. The application of the sampling technique and scouting time for cucumber beetle management are discussed.

In many states, Japanese beetle,Popillia japonica Newman (Coleoptera: Scarabeidae), is no longer quarantined, and management is left to professional applicators and consumers. Adult management in hybrid tea rose,Rosa L., was compared among biorational insecticides, novel imidacloprid applications (tablet, gel, and root dip), and conventional insecticides. Efficacy of biorational insecticides used by consumers varied widely and may not offer predictable management: mortality was 3.0% with Garlic Barrier, 5.0% with Monterey Neem Oil, 15.1% with Pygenic (1.4% pyrethrins), and 27.3% with Orange Guard (d–limonene). Only JB Killer (0.02% pyrethrins plus 0.2% piperonyl butoxide) had mortality of 90.9%, probably due to piperonyl butoxide. Professional biorationals did not show significant mortality: 7.7% with Azatin XL (azadirachtin) and 3.7% Conserve (spinosad). In contrast, conventional insecticides demonstrated significant mortality; 88.4% with Decathlon 20 WP (cyfluthrin) and 83.3% with Discus SC (imidacloprid plus cyfluthrin). New imidacloprid applications (tablet, gel, and root dip) worked as well as standard drench and granular methods, but they showed 9.1–42.7% mortality. However, beetles were incapacitated as demonstrated by inability to walk (82–106-s flip time) compared with controls (30-s flip time). No phytotoxicity was observed in any treatments. However, some imidacloprid treatments produced growth enhancement: higher leaf chlorophyll (1X, 3X granular, and one tablet), and larger leaf area and higher nitrogen (3X granular, drench). The highest (active ingredient) imidacloprid was in 3X granular treatment, which in an unplanned infestation, showed highest numbers of twospotted spider mite,Tetranychus urticae Koch (Acari: Tetranychidae). Effects of imidacloprid on leaf quality and mite outbreaks deserves research.

First-generation cabbage maggot,Delia radicum (L.) (Diptera: Anthomyiidae), can cause extensive damage to newly transplanted brassica crops. This study investigated the use of relay cropping, a form of intercropping that involves overlapping two crops in the same field for a short period, as a means to 1) reduce first-generationD. radicum egg numbers by disrupting female host finding and 2) minimize yield loss by reducing the time that crops overlap. Because of the high incidence of two otherDelia species,Delia platura (Meigen) andDelia florilega (Zetterstedt), treatment effects on these insects also were considered. In both years of the study (2003 and 2004), there were fewerD. radicum eggs collected from the base of cauliflower,Brassica oleracea varietybotrytis, plants relay cropped with lettuce,Lactuca sativa L., than in monoculture.D. platura/D. florilega also laid fewer eggs on cauliflower in the relay crop than in monoculture in 2003, but in 2004 the opposite was true, there were moreD. platura/D. florilega eggs laid on the relay-cropped cauliflower. After peakD. radicum oviposition, the lettuce was harvested. Cauliflower curd weights and diameters were comparable between treatments in both years. Plant loss because ofD. platura/D. florilega feeding in the 2004 relay-cropped plots resulted in reduced yields in these plots compared with the monoculture. Although further investigation is needed into the effects of relay cropping on other pests within this system, this is the first study to demonstrate that relay cropping can reduce egg laying byD. radicum at the scale studied while minimizing competition between component crops for key resources.

Studies were conducted to investigate the effects of a kaolin-based hydrophilic particle film, Surround WP, on the biology and behavior of the psyllidDiaphorina citri Kuwayama (Hemiptera: Psyllidae) and to assess population densities ofD.citri in citrus subjected to monthly applications of Surround WP. Laboratory investigations indicated a 3% (wt:vol) suspension of Surround WP in water applied directly was not acutely toxic to eggs, older nymphs or adults. Presence of the dried particle film on leaves interfered with the ability of adults to grasp and walk on citrus leaves. During a 30-s period, adults spent an average of 5 s moving on leaves with particle film compared with 16 s on leaves without particle film. When leaves were inverted, a significantly higher percentage of adults fell or flew from treated leaves (53%) than untreated leaves (16%). In a 12-mo study investigating infestations ofD.citri on citrus treated monthly with Surround WP, cumulative reductions of 78% in adult numbers on mature leaves and of 60% in adult numbers on flush shoots (immature leaves) were observed in treated trees compared with untreated trees. Numbers of eggs and nymphs per flush shoot were reduced by 85 and 78%, respectively, in trees treated with particle film. Reductions in infestation levels ofD.citri in treated trees were attributed to the negative effects of the particle film on the ability of adults to grasp, move, and oviposit. The suppressive effects of a Surround treatment against adult psyllids were degraded by rain.

A 3-yr field study was conducted at commercial grape (Vitis spp.) farms to evaluate insect management programs for control of the grape berry moth,Paralobesia viteana Clemens (Lepidoptera: Tortricidae) and conservation of natural enemies. At each farm, one vineyard received only reduced-risk insecticides for control of second and third generationP. viteana, whereas the comparison vineyard received conventional insecticides. Both vineyards received a conventional insecticide application for control of first generationP. viteana and other insect pests. Monitoring with pheromone traps showed no differences between programs in the total number of adult male moths trapped in vineyards, and oviposition byP. viteana was similar between the two programs in all 3 yr. During weekly samples of crop infestation, both programs had a similar percentage of clusters infested byP. viteana larvae. Berries infested byP. viteana were collected from vineyard borders during the second and thirdP. viteana generations and held under controlled conditions. In eight of the nine berry samples, survival of larvae was significantly lower in berries collected from vineyards managed under the reduced-risk insecticide program compared with the conventional program. Parasitism ofP. viteana larvae in these samples was not consistently different between the two insecticide programs over 3 yr, and similar captures of natural enemies were found on yellow sticky traps in the two programs throughout the study. Our results indicate that integrated pest management programs incorporating reduced-risk insecticides for control ofP. viteana can obtain similar or greater control ofP. viteana compared with programs based solely on conventional insecticides, but they may not lead to measurable long-term increases in parasitism ofP. viteana.

Ku Shen,Sophora flavescens Aiton (Leguminosae), contains alkaloids that possess broad biological activities. This study showed that total matrines (a mixture of the alkaloids), and matrine and oxymatrine (two major alkaloids) had a strong antifeedant effect against Formosan subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), at all tested concentrations (ranging from 0.01 to 5%). Total matrines and matrine also had significantly toxic effects at 5%. The estimated LD₅₀ of total matrines and matrine was 12.3 and 8.6 μg per insect, respectively, after 24 h; 13.3 and 7.1 μg per insect after 48 h; and 10.1 and 4.8 μg per insect after 1 wk. The antifeedant and toxic properties of total matrines- and matrine-treated wood remained effective at least 12 mo after treatment under both light and dark storage conditions. These chemicals have great potential for commercial development as wood treatment agents.

Sixteen linear ethoxylated alcohol surfactants (AEOs) were studied to determine their contact insecticidal activity to adult German cockroaches,Blattella germanica (L.) (Blattodea: Blattellidae). Within groups of AEOs of equal carbon chain length, insecticidal activity, measured as LT₅₀ values (in minutes) and 24-h mortality after treatment, was inversely related to the amount of ethoxylation. There was a highly significant negative relationship between the hydrophile-lipophile balance (HLB) value of the AEO and contact toxicity. The AEO with the lowest HLB value, Tomadol 23-1 (HLB = 3.7), produced the greatest 24-h cockroach mortality. The contact activity of Tomadol 23-1 was evaluated against a wide range of other insect species. Most species were killed within 24 h by direct exposure (1–4 μl of a 50% ethanol solution) to Tomadol 23-1 or by spray exposure to an aqueous solution. Tomadol 23-1, at a sublethal concentration, was tested in combination with representative members of the carbamate, nicotinoid, organophosphate, pyrethrum, pyrethroid, and pyrrole insecticide classes. Significant synergism was demonstrated in combinations of Tomadol 23-1 and chlorfenapyr, clothianidin, imidacloprid, thiamethoxam, and pyrethrum. Tomadol 23-1 significantly reduced the insecticidal activity of propoxur, suggesting antagonism. The insecticidal activity of Tomadol 23-1 was synergized by coapplication with a sublethal amount of piperonyl butoxide, indicating the involvement of cytochrome P450 microsomal monooxygenases in insect metabolism of AEO surfactants.

The Formosan subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), accidentally brought into the United States, has become a major urban pest, causing damage to structures and live trees. Because of increasing restrictions on the use of conventional termiticides, attention is focused on finding safer alternative methods for termite management. Oil from citrus peel, referred to here as orange oil extract (OOE), contains ≈92%d-limonene, and it is generally known to be toxic to insects. In laboratory experiments, 96 and 68% termites were killed in 5 d when OOE at 5 ppm (vol:vol) was dispensed from the top or bottom, respectively, with termites held at the opposite end of a tight-fitting plastic container. Apart from high mortality, workers exposed to vapor consumed significantly less filter paper than controls. However, when termites were exposed to OOE vapor, even at 10 ppm, in the void of a model wall, there was very little mortality. Termites did not tunnel through glass tubes filled with sand treated with 0.2 or 0.4% OOE. Sand treated with OOE was extracted each week for 8 wk to determine the remaining amount ofd-limonene. Results indicated that there was a sharp decline in the quantity ofd-limonene during the first 3 wk to a residual level that gradually decreased over the remaining period. With a suitable method of application and in combination with other control practices, OOE can be effectively used for the control of subterranean termites.

The binary mixtures of pyrethroids cypermethrin, α-cypermethrin, ζ-cypermethrin, bifenthrin, fenpropathrin, λ-cyhalothrin, and deltamethrin plus organophosphates ethion, profenofos, chlorpyrifos, quinalphos, acephate, methamidophos, methyl parathion, and triazophos were evaluated on putatively resistant field populations ofBemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) from Pakistan using a leaf-dip bioassay. Ethion exhibited good potentiation with all the pyrethroids. Quinalphos potentiated cypermethrin, fenpropathrin, and λ-cyhalothrin but not bifenthrin. Acephate was potentiating with bifenthrin and fenpropathrin but antagonistic with ζ-cypermethrin. A potentiation effect was also found when methamidophos was mixed with bifenthrin and fenpropathrin. However, profenofos was antagonistic with cypermethrin, bifenthrin, and λ-cyhalothrin. Similarly, bifenthrin methyl parathion and deltamethrin triazophos mixtures were antagonistic when tested on several populations ofB.tabaci. Chlorpyrifos was antagonistic with cypermethrin but had an additive effect with fenpropathrin.

Transgenic cotton,Gossypium hirsutum L., expressing thecry1Ac andcry2Ab genes fromBacillus thuringiensis (Bt) Berliner varietykurstaki in a pyramid (Bollgard II) was widely planted for the first time in Australia during the 2004–2005 growing season. Before the first commercial Bollgard II crops, limited amounts of cotton expressing only the cry1Ac gene (Ingard) was grown for seven seasons. No field failures due to resistance to Cry1Ac toxin were observed during that period and a monitoring program indicated that the frequency of genes conferring high level resistance to the Cry1Ac toxin were rare in the major pest of cotton,Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Before the deployment of Bollgard II, an allele conferring resistance to Cry2Ab toxin was detected in field-collectedH. armigera. We established a colony (designated SP15) consisting of homozygous resistant individuals and examined their characteristics through comparison with individuals from a Bt-susceptible laboratory colony (GR). Through specific crosses and bioassays, we established that the resistance present in SP15 was due to a single autosomal gene. The resistance was recessive. Homozygotes were highly resistant to Cry2Ab toxin, so much so, that we were unable to induce significant mortality at the maximum concentration of toxin available. Homozygotes also were unaffected when fed leaves of a cotton variety expressing the cry2Ab gene. Although cross-resistant to Cry2Aa toxin, SP15 was susceptible to Cry1Ac and to the Bt product DiPel.

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a well-known polyphagous insect pest. Mating compatibility among the insects occurring on different host plants is essential for free gene flow among populations. We tested the extent of crossability and fecundity of the insects that survived onBacillus thuringiensis (Bt) cotton with those occurring on pigeon pea,Cajanus cajun (L.) Millsp., non-Bt cotton,Gossypium hirsutum L.; sunflower,Helianthus annuus; sorghum,Sorghum bicolor L. Moench.; okra,Abelmoschus moschatus Medikus; chickpea,Cicer arietinum L.; marigold,Tagetes spp.; and tomato,Lycopersicum esculentum L., crops. The insects from different crops were freely crossable with those collected from Bt cotton and among themselves. The average fecundity across different crosses ranged from 314.1 to 426.3 in direct and from 305.8 to 421.7 eggs per female in reciprocal crosses. In any given cross, a minimum of 85.89% egg hatch was recorded. Furthermore, the F₁ individuals of different cross combinations were found to cross freely with their parents (BC₁) and among themselves with similar fecundity and egg hatch. High crossability amongH.armigera occurring on different host plants suggests that crop mosaics that may exist in countries such as India could play an important role as natural, nonstructured refugia and prolong the durability of the genes deployed for controlling this insect.

Bioassays and binding tests between Cry toxins (Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Ab) and brush-border membrane vesicles (BBMVs) from larvae of aBacillus thurningiensis (Bt)-susceptible (96S) and two Cry1Ac-resistant strains (BtR and LFR₁₀) were conducted for investigating cross-resistance of Cry1Ac-resistant strains to Cry2Ab inHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). The resistance ratio (RR) values of the BtR and LFR₁₀ strains to Cry1Ac and Cry2Ab were 2,971- and 1.1-fold and 253- and 1.0-fold, respectively, indicating that there was no cross-resistance to Cry2Ab. The binding experiments between Cry toxins and BBMVs from BtR, LFR₁₀, and 96S larvae showed that all of the toxins could bind with these BBMVs, but the Cry2Ab could not displace¹²⁵I labeled Cry1Ac and Cry1Ab. The same results were observed in reciprocal binding tests, demonstrating that Cry1A and Cry2Ab had different binding sites inH.armigera and providing a potential mechanism for the lack of cross-resistance between Cry1A and Cry2Ab toxins. These results suggest that the transgenic cotton,Gossypium hirsutum L., expressingCry1Ac andCry2Ab genes may be deployed for management of Cry1Ac resistantH.armigera.

The genetic basis of spinosad resistance was investigated in the western flower thrips,Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). The resistant strain, selected in the laboratory for spinosad resistance from a pool of thrips populations collected in Almeria (southeastern Spain), showed a very high resistance to spinosad (356,547-fold based on LC₅₀ values) compared with the laboratory susceptible strain. Mortality data from reciprocal crosses of resistant and susceptible thrips indicated that resistance was autosomal and not influenced by maternal effects. Analysis of probit lines from the parental strains and reciprocal crosses showed that resistance was expressed as an almost completely recessive trait. To determine the number of genes involved, a direct test of monogenic inheritance based on the backcrosses suggested that resistance to spinosad was probably controlled by one locus. Another approach, which was based on phenotypic variances, showed that n_E, or the minimum number of freely segregating genetic factors for the resistant strain, equaled 0.59.

Susceptibilities of 82 bollworm,Helicoverpa zea (Boddie), and 44 tobacco budworm,Heliothis virescens (F.) (Lepidoptera: Noctuidae), populations to Cry2Ab2 protein were measured in diet incorporated assays at the University of Arkansas from 2002 to 2005. Resulting data were used to calculate overall (pooled data) estimates of species susceptibility for future benchmarks of resistance. Variabilities among populations also were studied by comparing regressions for individual populations and calculating mean susceptibilities for different subgroups of the colonies studied. Individual lethal concentration (LC₅₀) estimates for nine laboratory, seven laboratory-cross, and 28 field populations ofH.virescens varied up to 48-fold when adjusted for the response of the most susceptible laboratory colony studied. Mean susceptibilities of all laboratory, laboratory-cross, or field colonies varied only two-fold. When grouped by host plants, populations collected on tobacco,Nicotiana tabacum (L.), seemed to be less susceptible than those collected on other host plants. Individual LC₅₀ values for 82 laboratory, laboratory-cross and field populations ofH.zea varied up to 37-fold. Mean LC₅₀ values of all laboratory, laboratory-cross, or field populations varied only three-fold. Susceptibilities of populations from Bollgard cotton were up to four-fold less than those fromBacillus thuringiensis corn,Zea mays L. Field populations collected during late season were generally less susceptible than those collected early in the season. Across the two species,H.zea was less sensitive to Cry2Ab2 thanH.virescens. Both species seem to be less sensitive to Cry2Ab2 than to Cry1Ac.

Bioassays (at generation G₂) with a newly collected field population (designated CH4) ofPlutella xylostella (L.) (Lepidoptera: Plutellidae) from farms in the Cameron Highlands, Malaysia, indicated resistance to acetamiprid, deltamethrin, lambda-cyhalothrin, and esfenvalerate. At G₃, the field-derived population was divided into two subpopulations, one subpopuplation was selected (G₃ to G₁₀) with acetamiprid (aceta-SEL), whereas the second subpopulation was left unselected (UNSEL). A significant reduction in the resistance ratio for each compound was observed in UNSEL at G₁₁, indicating that the observed resistance to each insecticide was unstable. For aceta-SEL, bioassays at G₁₁ found that selection with acetamiprid gave a resistance ratio of 409 compared with UNSEL. The LC₅₀ values for deltamethrin, lambda-cyhalothrin, and esfenvalerate to aceta-SEL were similar at both G₁₁ and G₂. This suggests that acetamiprid selection maintained the otherwise unstable resistance to these compounds in the aceta-SEL population. Logit regression analysis of F₁ reciprocal crosses between aceta-SEL and the susceptible Lab-UK indicated that resistance to acetamiprid was inherited as an autosomal, incompletely recessive (D_LC = 0.26) trait. Tests of monogenic inheritance and weight distribution suggested that resistance to acetamiprid was controlled by a single locus.

Genetic relationships within and among seven Iranian native silkworm strains was determined by DNA fingerprinting by using amplified fragment length polymorphism (AFLP) markers. In total, 189 informative AFLP markers were generated and analyzed. Estimates of Nei’s gene diversity for all loci in individual strains showed a higher degree of genetic similarity within each studied strain. The highest and the least degrees of gene diversity were related to Khorasan Pink (h = 0.1804) and Baghdadi (h = 0.1412) strains, respectively. The unweighted pair-group method with arithmetic average dendrogram revealed seven strains of silkworm,Bombyx mori (L.), resolving into two major clusters. The highest degree of genetic similarity was related to Baghdadi and Harati White, and the least degree was related to Guilan Orange and Harati Yellow. The genetic similarity estimated within and among silkworms could be explained by the pedigrees, historical and geographical distribution of the strains, effective population size, inbreeding rate, selection intensity, and gene flow. This study revealed that the variability of DNA fingerprints within and among silkworm strains could provide an essential basis for breeders in planning crossbreeding strategies to produce potentially hetrotic hybrids in addition to contributing in conservation programs.

A complete NADPH-cytochrome P450 reductase (CPR) cDNA was isolated fromAnopheles minimus Theobald mosquitoes by using reverse transcription-polymerase chain reaction-based methods. The complete cDNA contains 2,040 bp encoding the protein of 679 amino acids, with a calculated molecular mass of 77.3 kDa. The deduced amino acid sequence had a typical feature of CPR by possessing conserved domains involved in binding of flavin mononucleotide, flavin adenine dinucleotide, and NADPH cofactors. The complete CPR cDNA was expressed as 6x His-tagged fusion protein in both membrane and cytosolic fractions inEscherichia coli, both fractions contained NADPH-cytochromec reducing activity. The membrane-bound form containing N-terminal membrane anchor was subjected to purification, andK_m values were determined for NADPH and cytochromec. The purified CPR enzyme was functionally active, as demonstrated by its ability to support CYP6AA3-mediated metabolism in the reconstituted reaction in vitro. Initial test suggested that CYP6AA3 could play a role in deltamethrin metabolism.

Fall armyworm,Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a major economic pest throughout the Western Hemisphere. Populations can be subdivided into two morphologically identical but genetically distinct strains (corn-strain and rice-strain) that differ in their host plant preferences. These strains can be distinguished by using polymorphisms in the mitochondrialcytochrome oxidase I gene. Additional sequence analysis of this locus identified two sites that were highly polymorphic in the corn-strain population and that produced four different haplotype subgroups. Comparisons of the frequency distribution of these haplotypes found no seasonal or plant host specificities, but they did demonstrate that the Brazil corn-strain population is different from corn-strain fall armyworm found in Florida. The development of a rapid means of distinguishing fall armyworm populations originating from Brazil versus Florida provides an opportunity for investigating and comparing the genetic complexity and long-range movements of this important agricultural pest.

Sixty-five soybean,Glycine max (L.) Merrill, breeding lines containing ‘IAC-100′ in their pedigrees were evaluated for their resistance to lepidopteran defoliation in replicated field trials during 2001–2005. Three soybean cultivars, IAC-100 (with resistance to stink bug [Hemiptera: Pentatomidae] feeding), ‘Dillon’, and ‘Hutcheson’, also were included in the evaluations. The percentage defoliation among these 68 entries ranged from 4.3 to 28.3% in 2001 and from 35.0 to 99.0% in 2002. Lepidopteran caterpillars, primarilyAnticarsia gemmatalis Hübner, but also somePseudoplusia includens (Walker) andHypena scabra (F.), peaked at 14.3 per row-meter on 11 September 2001 and at 39.7 per row-meter on 22 August 2002. Twenty-six entries with better resistance potential, plus two cultivars, were selected for continued evaluations in 2003 and 2004. Defoliation ranged from 23.3 to 56.7% among the 28 entries in 2003 and from 16.3 to 42.5% in 2004, with peak caterpillar densities of 20.3 per row-meter on 17 September 2003 and 14.5 per row-meter on 8 September 2004. From these differential responses, 12 entries were included for advanced resistance evaluations in 2005. The breeding line entries 52 (IAC-100 × V89-1301), 23 (IAC-100 × V89-1301), and 14 (IAC-100 × V71-370), plus entry 37 (IAC-100) had lower defoliation rankings during all 5 yr of this study, with the entry having the lowest defoliation ranked 1 and the entry with highest defoliation ranked either 68, 28, or 12, based on the number of entries evaluated each year. The overall mean rankings of these four entries over the 5 yr of this study were 4.4, 3.0, 4.2, and 4.6, respectively. A fifth entry, 30 (IAC-100 × V71-370), was in the top group with lower defoliation in 4 yr of this 5-yr study, and it had an overall mean ranking of 5.6. A sixth entry, 35 (Hutcheson × IAC-100), had moderate resistance (overall ranking of 19.2) compared with the standard Hutcheson (30.8 ranking of a possible highest ranking of 40.8). Entry 35 also yielded as well as the standard cultivars evaluated in the study. These lines will provide excellent sources for future soybean germplasm and varietal resistance development.

Southwestern corn borer,Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a major insect pest of corn,Zea mays L., in the southern United States. Germplasm lines with resistance to southwestern corn borer have been developed and released by the USDA–ARS. Two single-cross hybrids produced by crossing germplasm lines with resistance to southwestern corn borer and a susceptible single-cross hybrid were infested with southwestern corn borer larvae in a 2-yr field test conducted in Mississippi. The susceptible hybrid sustained significantly more leaf damage and stalk tunneling than either resistant hybrid. The number of tunnels and the length of tunneling were significantly lower on the resistant hybrids. In 2003, up to 15 times more tunneling was observed on the susceptible hybrid. Larvae feeding on the resistant hybrids were delayed in their movement from the whorl to the stalk and larval survival was 50% lower on the resistant hybrids than on the susceptible hybrid. Larvae recovered from the susceptible hybrid 7–14 d after infestation weighed twice as much as those recovered from the resistant hybrids. Similar differences in larval weight were observed in the laboratory when larvae were reared on diets prepared from lyophilized tissue from the three hybrids. These results provide a foundation for other investigations designed to identify and determine the roles of specific genes and gene families associated with southwestern corn borer resistance in corn.

The southwestern corn borer,Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a serious pest of corn,Zea mays L., in the southern United States. Corn germplasm lines with conventional genetic leaf-feeding resistance to this pest, the fall armyworm,Spodoptera frugiperda (J.E. Smith), and other lepidopterans have been released to the public by USDA–ARS scientists located in Mississippi. Recent studies suggest the insect resistant lines disrupt the integrity of the peritrophic membrane of the fall armyworm. The objectives of this study were to investigate any morphological differences in the structure of the peritrophic membrane of southwestern corn borer larvae feeding on resistant and susceptible corn hybrids and to quantify the damage. Larvae were reared under field and laboratory conditions on three corn hybrids (two resistant and one susceptible). Scanning electron microscopy was used to examine the peritrophic membrane for abnormalities such as holes or tears and to count the holes or tears in the membrane. Differences in the degree of damage to peritrophic membrane of larvae fed on resistant and susceptible plants were not detected. Up to five distinct layers of the membrane were observed in each larva. Variation in the amounts of damage to the peritrophic membrane observed from larvae feeding on all plant material was high. Plant resistance adversely affects growth and development of southwestern corn borer larvae, and further investigations are needed to explain the role of plant resistance and its relation to peritrophic membrane in southwestern corn borer larvae.

The soybean aphid,Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean,Glycine max (L.) Merr. Since 2000, whenA.glycines was detected in the United States, several studies on this insect have been done in different areas, but there is no report of any studies of stylet penetration behavior byA.glycines on resistant and susceptible soybean. Assessment of feeding behavior of this aphid species was compared on four resistant entries (K1639, Pioneer® 95B97, Dowling, and Jackson) and a susceptible check (KS4202) by using the electrical penetration graph (EPG) technique. Feeding behavior ofA.glycines adults was recorded during a 9-h period. The average time needed to reach the first sieve element phase byA.glycines was 3.5 h in KS4202, whereas it was 7.5 h in the resistant entries. The total duration in the sieve element phase was longer than an hour in KS4202, and only 2 to 7 min in the resistant entries. These results suggest that morphological or chemical factors in the phloem tissue of resistant plants affect stylet penetration activities ofA.glycines. In the majority of the recordings, however, the aphid stylet reached the xylem phase before penetrating the sieve element, and the time that aphids spent ingesting xylem sap was not different among all entries. Therefore, it is possible that xylem sap in the resistant entries may contain toxic substances that change aphid behavior and that affect further activities in the sieve element phase.

It is hypothesized that the interaction between aphids and plants follows a gene-for-gene model. The recent appearance of several new Russian wheat aphid,Diuraphis noxia (Kurdjumov) (Homoptera: Aphididae), biotypes in the United States and the differential response of wheat,Triticum aestivum L., genotypes containing different resistance genes also suggest a gene-for-gene interaction. However, aphid elicitors remain unknown. This study was conducted to identify fractionated Russian wheat aphid extracts capable of eliciting differential responses between resistant and susceptible wheat genotypes. We extracted whole soluble compounds and separated proteins and metabolites from two Russian wheat aphid biotypes (1 and 2), injected these extracts into seedlings of susceptible wheat Gamtoos (dn7) and resistant 94M370 (Dn7), and determined phenotypic and biochemical plant responses. Injections of whole extract or protein extract from both biotypes induced the typical susceptible symptom, leaf rolling, in the susceptible cultivar, but not in the resistant cultivar. Furthermore, multiple injections with protein extract from biotype 2 induced the development of chlorosis, head trapping, and stunting in susceptible wheat. Injection with metabolite, buffer, or chitin, did not produce any susceptible symptoms in either genotype. The protein extract from the two biotypes also induced significantly higher activities of three defense-response enzymes (catalase, peroxidase, and β-glucanase) in 94M370 than in Gamtoos. These results indicate that a protein elicitor from the Russian wheat aphid is recognized by a plant receptor, and the recognition is mediated by theDn7-gene product. The increased activities of defense-response enzymes in resistant plants after injection with the protein fraction suggest that defense response genes are induced after recognition of aphid elicitors by the plant.

To develop a practical integrated pest management (IPM) system for the multicolored Asian lady beetle,Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in wine grapes, we assessed the spatial distribution ofH.axyridis and developed eight sampling plans to estimate adult density or infestation level in grape clusters. We used 49 data sets collected from commercial vineyards in 2004 and 2005, in Minnesota and Wisconsin. Enumerative plans were developed using two precision levels (0.10 and 0.25); the six binomial plans reflected six unique action thresholds (3, 7, 12, 18, 22, and 31% of cluster samples infested with at least oneH.axyridis). The spatial distribution ofH.axyridis in wine grapes was aggregated, independent of cultivar and year, but it was more randomly distributed as mean density declined. The average sample number (ASN) for each sampling plan was determined using resampling software. For research purposes, an enumerative plan with a precision level of 0.10 (SE/X̄) resulted in a mean ASN of 546 clusters. For IPM applications, the enumerative plan with a precision level of 0.25 resulted in a mean ASN of 180 clusters. In contrast, the binomial plans resulted in much lower ASNs and provided high probabilities of arriving at correct “treat or no-treat” decisions, making these plans more efficient for IPM applications. For a tally threshold of one adult per cluster, the operating characteristic curves for the six action thresholds provided binomial sequential sampling plans with mean ASNs of only 19–26 clusters, and probabilities of making correct decisions between 83 and 96%. The benefits of the binomial sampling plans are discussed within the context of improving IPM programs for wine grapes.

Lariophagus distinguendus Förster (Hymenoptera: Pteromalidae) has been suggested as a biological control agent against the granary weevil,Sitophilus granarius (L.), in grain stores. Information on the effect of low temperatures prevailing in grain stores is necessary to be able to predict the potential of this parasitoid againstS.granarius in temperate regions, where grain is cooled with ambient air to achieve safe storage conditions. The influence of constant temperatures of 16, 18, and 20°C on life table parameters and parasitoid-induced mortality (PIM) was investigated in the laboratory.L.distinguendus is able to develop and reproduce at temperatures as low as 16°C. The intrinsic rate of natural increase,r_m, was 0.0182, 0.0222, and 0.0792 d⁻¹ at 16, 18, and 20°C, respectively. The proportion of hosts killed due to parasitoid-induced mortality was highest at 20°C. At this temperature, it amounted to 70% of the total mortality exerted by the parasitoid; at 18 and 16°C, it was 57 and 42% of the total, respectively.L.distinguendus is a promising biocontrol agent for grain stores in temperate regions because it is able to develop and reproduce at temperatures down to 16°C; its development is quicker than that of its host, estimated from the literature; and it kills many hosts in addition to those used for reproduction.

The potential for pheromone-based mating disruption (MD) ofEphestia kuehniella (Walker) andPlodia interpunctella (Hübner) (Lepidoptera: Pyralidae) was investigated in two flour mills and a pet food distributor. Plastic sachets emitting 2–3 mg per d (Z,E)-9,12-tetradecadienyl acetate, the major pheromone component of both moth species, were used as MD dispensers, which were applied in grid systems resulting in one dispenser per 100 m³ of air volume. Pheromone traps with sticky inserts were used to monitor moth population fluctuations. To monitor pheromone levels in the air before, during, and after the treatment, electroantennographic (EAG) measurements were performed using a portable device. All localities showed decreased trap catches after application of MD. In two localities with low initial population densities, trap catches were reduced immediately after application of MD and remained very low, even several months after the MD treatment was terminated. In contrast, in a locality with a higher initial population density the reduction in trap catches was slower, and trap catches increased again soon after the termination of the MD treatment. Electrophysiological data showed not only increased aerial levels of pheromone during the treatment period but also levels that were higher than during pretreatment, even 12 mo after removal of MD dispensers. The localities had good ventilation, and the memory effect observed indicates that the pheromone adhered to surfaces that subsequently functioned as secondary dispensers. Customer complaints registered by one of the mills were 49% less in 2004, after 2 yr of MD compared with 2002, the year before the treatments began.