Trapping strategy and diel periodicity affect capture rate of Halyomorpha halys (Hemiptera: Pentatomidae) in agroecosystems.

The polyphagous pest, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), damages fruit in orchards and field crops and is often found within nearby woodlands. Pheromone-baited traps can be used to monitor H. halys. However, the efficiency of trapping H. halys may vary depending on trapping strategy (live vs. dead capture), location (ground or canopy), and diel periodicity of captures. We compared H. halys capture within fruiting hosts for: (i) live and kill traps on the ground vs. traps in the canopy of black cherry (Prunus serotina Ehrh.) (Rosales: Rosaceae), sugarberry (Celtis laevigata Willdenow) (Rosales: Cannabaceae), and pecan (Carya illinoinensis (Wangenh.) K. Koch) (Fagales: Juglandaceae) trees, (ii) ground and canopy-live traps in sassafras (Sassafras albidum (Nutt.) Nees) (Laurales: Lauraceae), and (iii) whether diel periodicity was detected for live capture in sassafras and cotton. More H. halys adults and nymphs were captured in kill traps than in live traps. More nymphs were captured in kill traps in black cherry and sugarberry on the ground than in the canopy. Live adult capture was significantly greater in sassafras and pecan canopies than on the ground. In cotton and sassafras, more live adults were captured from 8 PM-noon, with the fewest captured from noon-6 PM. A better understanding of stink bug activity in the field allows for improved trapping and, possibly, improved timing of treatment applications.

Seasonal density and natural mortality of Halyomorpha halys (Stål) and indigenous stink bugs (Hemiptera: Pentatomidae) in a field crop agroecosystem.

Stink bugs (Hemiptera: Pentatomidae), including the exotic Halyomorpha halys (Stål), Nezara viridula (L.), and other indigenous species, are pests that damage a variety of agricultural crops. At a study site in the southeastern United States, we measured the density of stink bug species and patterns of parasitism and predation on corn, cotton, and soybean and host trees in an adjacent woodline. We assessed parasitism and predation of naturally laid egg masses in crops and sentinel egg masses in host trees and used pheromone-baited traps to determine H. halys seasonal development. Overall, H. halys and N. viridula were the dominant bugs observed. Adult H. halys were first detected each year on trees, followed by corn, and then cotton and soybean, suggesting that trees served as a source of H. halys dispersing into crops. For H. halys, more nymphs were captured in soybean than in corn or cotton. For N. viridula, more adults were captured in corn and cotton than in soybean, and more nymphs were captured in corn during 2019 and 2021 than in 2020. Percentage parasitism of N. viridula egg masses (74.2%) was higher than than that for H. halys egg masses (54.3%). Accordingly, conservation biological control has the potential to enhance parasitism of indigenous stink bugs and H. halys in field crop agroecosystems.

Low Incidence of Avian Predation on the Brown Marmorated Stink Bug, Halyomorpha halys (Hemiptera: Pentatomidae), in Southeastern Orchard Systems.

In many agroecosystems, brown marmorated stink bugs (Halyomorpha halys) (Hemiptera: Pentatomidae) are polyphagous pests that cause significant economic losses to numerous crops every year. Insectivorous birds may provide a means of sustainable predation of invasive pests, such as H. halys. In forest margins surrounding peach, pecan, and interplanted peach-pecan orchards, we monitored H. halys populations with pheromone-baited traps, mist-netted birds, and collected avian fecal samples for molecular gut content analysis. We screened 257 fecal samples from 19 bird species for the presence of H. halys DNA to determine whether birds provide the biological control of this pest. Overall, we found evidence that four birds from three species consumed H. halys, including Northern cardinal (Cardinalis cardinalisis), Tufted titmouse (Baeolophus bicolor), and Carolina wren (Thryothorus ludovicianus). Halyomorpha halys captured in traps increased over time but did not vary by orchard type. Although incidence of predation was low, this may be an underestimate as a result of our current avian fecal sampling methodology. Because birds are members of the broader food web, future studies are needed to understand avian ecosystem services, especially in terms of pest control, including H. halys and other pest species.

Predation and parasitism of naturally occurring and sentinel stink bug egg masses of Halyomorpha halys (Stål) and Nezara viridula (L.) (Hemiptera: Pentatomidae) in various southeastern habitats.

Stink bugs, including Halyomorpha halys (Stål) and Nezara viridula (L.), are agricultural pests that feed on fruit in a variety of crops. Monitoring predation and parasitism of stink bug egg masses furthers our understanding of potential biological control tactics. However, best practices for laboratory and field assessments of parasitism and predation of egg masses require further attention. We carried out a series of laboratory and field experiments to test whether parasitism and predation for three types of sentinel H. halys egg masses, fresh, frozen, and refrigerated, varied in agricultural commodities. In addition, we asked if predation and parasitism differed between sentinel and naturally occurring H. halys and N. viridula egg masses in soybean. In the laboratory, more H. halys eggs were parasitized by Trissolcus euschisti (Ashmead) (Hymenoptera: Scelionidae) if they were frozen or refrigerated compared to fresh eggs. Similarly, in the field, parasitism was higher for frozen egg masses than fresh. In 2018 and 2019, H. halys natural egg masses had higher parasitism and lower predation compared to sentinel egg masses in soybean. In a paired field test during 2020 and 2021, there was no difference in parasitism between H. halys natural and sentinel eggs, but much higher incidence of parasitism was detected in natural N. viridula egg masses than sentinel eggs. Collecting natural egg masses is the best methodology for field assessment of parasitism of stink bug egg masses; however, if natural egg masses are not easily available, deploying refrigerated sentinel egg masses is a good alternative.

Spatiotemporal Distribution of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Across a Fruit and Tree Nut Agricultural Ecosystem.

The invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a mobile, polyphagous agricultural pest that feeds on a variety of plants. In orchard systems, seasonal monitoring of adults and nymphs in fruit and nut trees and noncrop host plants in surrounding habitat can be used to identify, in time and space, areas of high-density aggregations to develop targeted pest management strategies. We explored the spatiotemporal distribution of H. halys adults and nymphs and assessed whether seasonal distribution patterns varied according to habitat. From 2018 to 2021, pheromone-baited traps were placed in orchard and noncrop plants to first document the establishment of H. halys at this site and to describe seasonal development. In addition, stink bugs were monitored weekly during 2019-2020 across a grid of baited traps placed within the orchard ecosystem. Based on grid data, we used Spatial Analysis by Distance Indices (SADIE) to identify significant clusters of H. halys and visualized aggregations with interpolated maps. Overall, the distribution of H. halys adults and nymphs were similar; both aggregated primarily in peach and adjacent woodlands followed by pecan. Timing of aggregations was consistent across years and reached the highest levels in July and August. Moreover, we document that H. halys is an established pest within this orchard ecosystem, and that noncrop host plants likely play an important role in maintaining populations of H. halys. To manage H. halys in southeastern orchard systems, growers may need to account for host plants in habitats that surround fruiting trees.

Spatiotemporal Distribution of Two Euschistus spp. Stink Bugs (Hemiptera: Pentatomidae) in Southeastern Farmscapes.

Stink bugs (Hemiptera: Pentatomidae) are ubiquitous, cryptic, phytophagous pests that are found in many crops. In agroecosystems, individuals disperse from adjacent noncrop hosts and tend to aggregate or cluster within fields. In this study, we characterized the distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) over 2 yr at three southeastern United States farmscapes. Stink bugs were captured in pheromone-baited traps, and Spatial Analysis by Distance Indices (SADIE) used to identify the location of significant aggregations by habitat type and season. Euschistus servus adults were more likely to be captured in pecan orchards, cotton, other crops, or unmanaged habitats than in woodland habitats. Significant aggregations of E. servus were detected in a variety of habitats including pecan, corn, cotton, peanut, and tobacco, as well as fallow and hay fields, pastures, and hedgerows. Fewer adult E. tristigmus were captured than E. servus adults, and E. tristigmus adults were typically trapped and aggregated in woodland habitats. The resulting data provide an important understanding regarding the seasonal movement and relative abundance levels of stink bug populations, which are critical to the development of integrated pest management strategies.

Influence of Pheromone-Baited Traps on Stink Bugs in Cotton.

Stink bugs (Hemiptera: Pentatomidae) are economic pests in fruit, vegetable, grain, and row crops worldwide. Pyramid traps baited with lures of stink bug aggregation pheromones capture these pests in the field, but stink bugs can congregate on plants near traps. Our specific objective was to examine the area of arrestment of stink bugs based on their density on cotton at different distances from pheromone-baited traps. We used lures of the aggregation pheromone of Euschistus spp., methyl (2E,4Z)-2,4-decadienoate (MDD), and Plautia stali Scott, methyl [2E,4E,6Z]-2,4,6-decatrienoate (MDT). Overall, Euschistus servus (Say), Euschistus tristigmus (Say), Chinavia hilaris (Say), and Nezara viridula (L.) were the main stink bug species on cotton. Over the 3-yr study, adult stink bug density was significantly higher on the row of cotton immediately adjacent to a pheromone-baited trap than on the second and third row from the trap. Stink bug density was significantly lower on the seventh cotton row beyond the trap in 2015, on the fourth, eighth, and 16th rows in 2017, and on the fourth and eighth rows in 2018 compared to the two or three rows nearest the trap. These results indicate that adult stink bugs congregated mainly on the three cotton rows (2.73 m in width) nearest a trap. Management strategies utilizing pheromone-baited traps for stink bug control, such as trap cropping in combination with traps, should take into consideration this area of arrestment.

Density and Egg Parasitism of Stink Bugs (Hemiptera: Pentatomidae) in Elderberry and Dispersal Into Crops.

Chinavia hilaris (Say), Euschistus servus (Say), Euschistus tristigmus (Say), and Thyanta custator custator (F.) (Hemiptera: Pentatomidae) are serious pests of crops in the southeastern United States but little is known concerning their dispersal from noncrop hosts in woodlands into crops. This 2-yr study was conducted to investigate whether elderberry [Sambucus nigra subsp. canadensis (L.) R. Bolli] in woodlands serves as a source of stink bugs dispersing into adjacent crops and to examine parasitism of C. hilaris and E. servus eggs on this plant. Elderberry was a reproductive host for each of the four stink bug species; females oviposited on plants with subsequent nymphs feeding on elderberry and developing into adults. Anastatus mirabilis (Walsh & Riley) (Hymenoptera: Eupelmidae), Anastatus reduvii (Howard), and Trissolcus edessae Fouts (Hymenoptera: Scelionidae) were prevalent egg parasitoids of C. hilaris but A. reduvii was the prevalent parasitoid of E. servus Newly developed stink bug adults were first detected on elderberry around mid-July. Then in late July and early August, as elderberry fruit senesced and cotton bolls became available, stink bugs began dispersing from elderberry into cotton based on recapture of stink bugs on cotton that had previously been marked on elderberry. In addition, in 2015, density of C. hilaris, E. servus, and E. tristigmus was higher in cotton with elderberry than in cotton without it. Over the study, economic threshold was reached for four of seven cotton fields. Elimination of elderberry in woodlands adjacent to cotton may be a viable management tactic for control of stink bugs in cotton.

Spatiotemporal Distribution of Chinavia hilaris (Hemiptera: Pentatomidae) in Peanut-Cotton Farmscapes.

The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States, but little is known concerning its spatiotemporal distribution in agricultural farmscapes. Therefore, spatiotemporal distribution of C. hilaris in farmscapes where cotton fields adjoined peanut was examined weekly. Spatial patterns of C. hilaris counts were analyzed using SADIE (Spatial Analysis by Distance Indices) methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops. For the six peanut-cotton farmscapes studied, the frequency of C. hilaris in cotton (94.8%) was significantly higher than in peanut (5.2%), and nymphs were rarely detected in peanut, indicating that peanut was not a source of C. hilaris into cotton. Significantly, aggregated spatial distributions were detected in cotton. Maps of local clustering indices depicted patches of C. hilaris in cotton, mainly at field edges including the peanut-to-cotton interface. Black cherry (Prunus serotina Ehrh.) and elderberry (Sambucus nigra subsp. canadensis [L.] R. Bolli) grew in habitats adjacent to crops, C. hilaris were captured in pheromone-baited stink bug traps in these habitats, and in most instances, C. hilaris were observed feeding on black cherry and elderberry in these habitats before colonization of cotton. Spatial distribution of C. hilaris in these farmscapes revealed that C. hilaris colonized cotton field edges near these two noncrop hosts. Altogether, these findings suggest that black cherry and elderberry were sources of C. hilaris into cotton. Factors affecting the spatiotemporal dynamics of C. hilaris in peanut-cotton farmscapes are discussed.

Spatiotemporal distribution of Chinavia hilaris (Hemiptera: Pentatomidae) in corn farmscapes.

The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States but little is known concerning its spatiotemporal distribution in corn cropping systems. Therefore, the spatiotemporal distribution of C. hilaris in farmscapes, when corn was adjacent to cotton, peanut, or both, was examined weekly. The spatial patterns of C. hilaris counts were analyzed using Spatial Analysis by Distance Indices methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops in corn-peanut-cotton farmscapes. This stink bug was detected in six of seven corn-cotton farmscapes, four of six corn-peanut farmscapes, and in both corn-peanut-cotton farmscapes. The frequency of C. hilaris in cotton (89.47%) was significantly higher than in peanut (7.02%) or corn (3.51%). This stink bug fed on noncrop hosts that grew in field borders adjacent to crops. The spatial distribution of C. hilaris in crops and the capture of C. hilaris adults and nymphs in pheromone-baited traps near noncrop hosts indicated that these hosts were sources of this stink bug dispersing into crops, primarily cotton. Significant aggregated spatial distributions were detected in cotton on some dates within corn-peanut-cotton farmscapes. Maps of local clustering indices depicted small patches of C. hilaris in cotton or cotton-sorghum at the peanut-cotton interface. Factors affecting the spatiotemporal dynamics of C. hilaris in corn farmscapes are discussed.

Physical barriers for suppression of movement of adult stink bugs into cotton.

Nezara viridula (L.), Euschistus servus (Say), and Chinavia hilaris (Say) (Heteroptera: Pentatomidae) are economic pests of cotton in the southeastern USA. Because adult stink bugs exhibit edge-mediated dispersal at crop-to-crop interfaces as they colonize cotton, strategic placement of physical barriers at these interfaces could manage these pests. The objective of this study was to determine the effectiveness of a physical barrier, either synthetic or plant-based, at the peanut-to-cotton interface for suppressing stink bugs that would move to cotton. In 2012 and 2013, sorghum sudangrass (2.4 and 2.1 m high, respectively) was significantly taller than cotton (1.4 and 1.3 m high, respectively) which was taller than peanut (0.4 and 0.5 m high, respectively). Buckwheat (0.6 m high), planted only in 2012, was significantly taller than peanut, but shorter than cotton. For both years of the study, sorghum sudangrass and a 1.8-m-high polypropylene barrier wall effectively deterred dispersal of stink bugs into cotton. Because each of these barriers was taller than cotton, their success in protecting cotton likely was due to disruption of the flight of stink bugs from low-growing peanut into cotton. The shortest barrier wall (0.6-m-high) did not suppress stink bug dispersal into cotton probably because it was approximately the same height as peanut. In 2012, flowering buckwheat increased the efficacy of Trichopoda pennipes (F.) attacking N. viridula in cotton although it did not deter dispersal of stink bugs. In conclusion, a barrier at least as tall as cotton can effectively retard the entry of stink bug adults into cotton.

Impact of brown stink bug (Heteroptera: Pentatomidae) feeding on corn grain yield components and quality.

Brown stink bug, Euschistus servus (Say) (Heteroptera: Pentatomidae), damage on developing corn, Zea mays L., ears was examined in 2005 and 2006 by using eight parameters related to its yield and kernel quality. Stink bug infestations were initiated when the corn plants were at tasseling (VT), mid-silking (R1), and blister (R2) stages by using zero, three, and six in 2005 or zero, one, two, and four bugs per ear in 2006, and maintained for 9 d. The percentage of discolored kernels was affected by stink bug number in both years, but not always affected by plant growth stage. The growth stage effect on the percentage of discolored kernels was significant in 2006, but not in 2005. The percentage of aborted kernels was affected by both stink bug number and plant growth stage in 2005 but not in 2006. Kernel weight was significantly reduced when three E. sercus adults were confined on a corn ear at stage VT or R1 for 9 d in 2005, whereas one or two adults per ear resulted in no kernel weight loss, but four E. servus adults did cause significant kernel weight loss at stage VT in 2006. Stink bug feeding injury at stage R2 did not affect kernel damage, ear weight or grain weight in either year. The infestation duration (9 or 18 d) was positively correlated to the percentage of discolored kernels but did not affect kernel or ear weight. Based on the regression equations between the kernel weight and stink bug number, the gain threshold or economic injury level should be 0.5 bugs per ear for 9 d at stage VT and less for stage R1. This information will be useful in developing management guidelines for stink bugs in field corn during ear formation and early grain filling stages.

Composition and abundance of stink bugs (Heteroptera: Pentatomidae) in corn.

The species composition and abundance of stink bugs (Heteroptera: Pentatomidae) in corn, Zea mays L., was determined in this on-farm study in Georgia. Seven species of phytophagous stink bugs were found on corn with the predominant species being Nezara viridula (L.) and Euschistus servus (Say). All developmental stages of these two pests were found, indicating they were developing on the corn crop. The remaining five species, Oebalus pugnax pugnax (F.), Euschistus quadrator (Rolston), Euschistus tristigmus (Say), Euschistus ictericus (L.), and Acrosternum hilare (Say), were found in relatively low numbers. Adult N. viridula were parasitized by the tachinid parasitoid Trichopoda pennipes (F.). There was a pronounced edge effect in distribution of stink bugs in corn. Population dynamics of N. viridula and E. servus were different on early and late-planted corn. Oviposition by females of both stink bug species occurred in mid-to-late-May and again mid-to-late-June in corn, regardless of planting date. In early planted fields, if stink bug females oviposited on corn in mid-July, the resulting nymphs did not survive to the adult stage in corn because ears were close to physiological maturity and leaves were senescing. Density of stink bug adults in early planted corn was relatively low throughout the growing season. In late-planted corn, females of both stink bug species consistently laid eggs in mid-to-late-July on corn with developing ears. This habitat favored continued nymph development, and the resulting adult population reached high levels. These results indicate that corn management practices play a key role in the ecology of stink bugs in corn agroecosystems and provide information for designing management strategies to suppress stink bugs in farmscapes with corn.

Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides.

Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.

Reproduction of Meloidogyne incognita on Winter Cover Crops Used in Cotton Production.

Substantial reproduction of Meloidogyne incognita on winter cover crops may lead to damaging populations in a subsequent cotton (Gossypium hirsutum) crop. The amount of population increase during the winter depends on soil temperature and the host status of the cover crop. Our objectives were to quantify M. incognita race 3 reproduction on rye (Secale cereale) and several leguminous cover crops and to determine if these cover crops increase population densities of M. incognita and subsequent damage to cotton. The cover crops tested were 'Bigbee' berseem clover (Trifolium alexandrinum), 'Paradana' balansa clover (T. balansae), 'AU Sunrise' and 'Dixie' crimson clover (T. incarnatum), 'Cherokee' red clover (T. pratense), common and 'AU Early Cover' hairy vetch (Vicia villosa), 'Cahaba White' vetch (V. sativa), and 'Wrens Abruzzi' rye. In the greenhouse tests, egg production was greatest on berseem clover, Dixie crimson clover, AU Early Cover hairy vetch, and common hairy vetch; intermediate on Balansa clover and AU Sunrise crimson clover; and least on rye, Cahaba White vetch, and Cherokee red clover. In both 2002 and 2003 field tests, enough heat units were accumulated between 1 January and 20 May for the nematode to complete two generations. Both AU Early Cover and common hairy vetch led to greater root galling than fallow in the subsequent cotton crop; they also supported high reproduction of M. incognita in the greenhouse. Rye and Cahaba White vetch did not increase root galling on cotton and were relatively poor hosts for M. incognita. Only those legumes that increased populations of M. incognita reduced cotton yield. In the southern US, M. incognita can complete one to two generations on a susceptible winter cover crop, so cover crops that support high nematode reproduction may lead to damage and yield losses in the following cotton crop. Planting rye or Meloidogyne-resistant legumes as winter cover crops will lower the risk of increased nematode populations compared to most vetches and clovers.

Comparison of susceptibility of pest Euschistus servus and predator Podisus maculiventris (Heteroptera: Pentatomidae) to selected insecticides.

Susceptibility of the brown stink bug, Euschistus serous (Say), and the spined soldier bug, Podisus maculiventris (Say), to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam, was compared in residual and oral toxicity tests. Generally, susceptibility of P. maculiventris to insecticides was significantly greater than or not significantly different from that of E. servus. Cyfluthrin and oxamyl were more toxic to the predator than to E. servus in residual and feeding tests, respectively. Dicrotophos is the only compound that exhibited both good residual and oral activity against E. servus, but even this toxicant was more toxic to the predator than to the pest in oral toxicity tests. Feeding on indoxacarb-treated food caused high mortality for both nymphs and adults of P. maculiventris. In contrast, E. servus was unaffected by feeding on food treated with this compound. Insecticide selectivity to P. maculiventris was detected only with acetamiprid for adults in residual toxicity tests and for nymphs in oral toxicity tests. Because insecticide selectivity to P. maculiventris was limited, it is extremely important to conserve P. maculiventris in cotton fields by applying these insecticides for control of brown stink bugs only when the pest reaches economic threshold.

Toxicity of a formulation of the insecticide indoxacarb to the tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), and the big-eyed bug, Geocoris punctipes (Hemiptera: Lygaeidae).

Indoxacarb is a new oxadiazine insecticide that has shown outstanding field insecticidal activity. The toxicity of a 145 g litre-1 indoxacarb SC formulation (Steward) was studied on the tarnished plant bug Lygus lineolaris and the big-eyed bug Geocoris punctipes. Both insect species responded very similarly to indoxacarb in topical, tarsal contact and plant feeding toxicity studies. The topical LD50 of the formulation was c 35 ng AI per insect for both species. Prolonged tarsal contact with dry indoxacarb residues did not result in mortality for either insect species. However, both species were susceptible to feeding through dried residues of indoxacarb after spraying on young cotton plants. Feeding on water-washed plants resulted in lower mortality than that observed with unwashed plants, and toxicity declined even more dramatically after a, detergent rinse, indicating that much of the indoxacarb probably resides on the cotton leaf surface or in the waxy cuticle. These results were corroborated by HPLC-mass spectrometry measurements of indoxacarb residues on the plants. Greater mortality for both species was observed in a higher relative humidity environment. Higher levels of accumulated indoxacarb and its active metabolite were detected in dead G punctipes than in L lineolaris after feeding on sprayed, unwashed plants. When female G punctipes ate indoxacarb-treated Heliothis zea eggs, there was significant toxicity. However, only c 15% of the females consumed indoxacarb-treated eggs, and the rest of the females showed a significant diminution of feeding in response to the insecticide. Cotton field studies have shown that indoxacarb treatments at labelled rates lead to a dramatic decline in L lineolaris, with negligible declines in beneficial populations. A major route of intoxication of L lineolaris in indoxacarb-treated cotton fields thus appears to be via oral, and not cuticular, uptake of residues from treated cotton plants. The mechanisms for selectivity/safety for G punctipes are currently under investigation and may be a combination of differential feeding behavior and diminution of feeding by females exposed to indoxacarb-treated eggs.