Journal of economic entomology最新文献

Pollination by the European honey bee, Apis mellifera, is essential for the production of many crops, including highbush blueberries (Vaccinum corymbosum). To understand the impact of agrochemicals (specifically, neonicotinoids, a class of synthetic, neurotoxic insecticides) on these pollinators, we conducted a field study during the blueberry blooms of 2020 and 2021 in British Columbia (B.C.). Forty experimental honey bee colonies were placed in the Fraser Valley: half of the colonies were located within 1.5 km of highbush blueberry fields ("near" colonies) and half were located more than 1.5 km away ("far" colonies). We calculated risk quotients for these compounds using their chronic lethal dietary dose (LDD50) and median lethal concentration (LC50). Pesticide risk was similar between colonies located near and far from blueberry forage, suggesting that toxicity risks are regionally ubiquitous. Two systemic neonicotinoid insecticides, clothianidin and thiamethoxam, were found at quantities that exceeded chronic international levels of concern. We developed a profit model for a pollinating beekeeper in B.C. that was parameterized by: detected pesticide levels; lethal and sublethal bee health; and economic data. For colonies exposed to neonicotinoid pesticides in and out of the blueberry forage radii, there were economic consequences from colony mortality and sublethal effects such as a loss of honey production and compromised colony health. Further, replacing dead colonies with local bees was more profitable than replacing them with imported packages, illustrating that beekeeping management selection of local options can have a positive effect on overall profit.

Nanoformulations of essential oils (EOs) improve stability of the active ingredient, and thereby its biological activity and persistence. Because compatibility of EOs with natural enemies is not explored sufficiently, we evaluated the impact of nanoformulations of EOs (aniseed, lemon) or pure products (farnesol) on different activities of the generalist predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). In dual choice bioassay, chrysopid larvae were significantly attracted to aniseed-treated pepper disks and deterred by farnesol. Larval activities (resting, walking, and preying) on treated leaves infested with Myzus persicae (Sulzer) (Hemiptera: Aphididae) were compared. There were no differences among nanoemulsions, nor aphid consumption varied. We studied the toxicity of nanoformulations to larvae and evaluated their development after contact with treated leaf disks, ingestion of treated artificial diet, and both routes of exposure (application of biopesticides on aphid-infested plants). This is the first evidence of the compatibility of EO nanoformulations with C. carnea by single route of exposure. Whether any effect appeared, it was sublethal. Compounds significantly reduced aphid consumption after 6 h on double route exposure, but this negative short-term effect disappeared as time progressed. Our results showed the optimal biopesticide to apply depends on which biological feature of the natural enemy we targeted. The key element to introduce these nanoemulsions is to match their persistence period on the crop with the release of the appropriate biological stage of C. carnea. This reinforces the fact that the main activities of C. carnea can be substantially maintained in joint application with nanoemulsions of EOs.

The diamondback moth, Plutella xylostella (Linnaeus), is one of the most important insect pests of Brassica crops worldwide. In October 2016, outbreaks of an invasive P. xylostella population and unexpected control failures occurred on broccoli and cauliflower crops throughout all vegetable-growing regions in Arizona. Nineteen populations of Plutella xylostella were collected from 2016 to 2021 from various commercial cauliflower fields in Yuma and Scottsdale, Arizona, and from experimental broccoli plots at the University of Arizona, Yuma Agricultural Center (UAYAC), Yuma, Arizona. Populations collected from the commercial cauliflower fields had been transplanted with seedlings produced in a local Yuma nursery in 2016 and Salinas, CA in 2017 to 2018, whereas experimental broccoli plots were direct seeded. These populations were evaluated for their susceptibility to chlorantraniliprole, spinetoram, emamectin benzoate, and cyantraniliprole. In this study, field rate laboratory bioassays, serial dilution laboratory bioassays, and field efficacy spray experiments were performed. The field rate laboratory bioassay results showed that spinetoram, emamectin benzoate, and cyantraniliprole remained effective at controlling P. xylostella, but chlorantraniliprole did not control P. xylostella at the field rate. Additionally, serial dilution bioassays confirmed significant levels of cyantraniliprole and chlorantraniliprole resistance in the P. xylostella populations collected from transplanted cauliflower fields. However, the results of the multiyear/growing-seasons study monitoring the susceptibility of P. xylostella populations collected from direct-seeded broccoli and field efficacy trials conducted at the UAYAC indicated that the resistance to diamide insecticides was neither uniform nor persistent following the 2016 outbreak. Nevertheless, the risk for P. xylostella resistance in Arizona vegetable-growing regions exists, particularly in Brassica transplants. Therefore, we recommend that Arizona Brassica growers remain vigilant and practice rigorous insecticide resistance management to offset the development of resistance.

Maximum dose bioassays were conducted to assess the efficacy of multiple registered active ingredients for diamondback moth (DBM), Plutella xylostella (L.), control in Georgia and Florida from 2021 to 2023 as a follow-up to an earlier study. Low efficacy (<40% mortality) was recorded for the highest labeled rate of Bacillus thuringiensis var. kurstaki strain ATBS-351 in Georgia, as well as chlorantraniliprole, cyantraniliprole, and cyclaniliprole in Georgia and Florida. The active ingredients with the highest efficacy (>80% mortality) in both states were naled, emamectin benzoate, and spinetoram. Independent analysis of data by state indicated that the efficacy of bifenthrin, chlorantraniliprole, cyantraniliprole, tolfenpyrad, and methomyl was higher in Florida populations than in Georgia populations. In addition, a comparison of these data to a recent DBM maximum dose survey in the same region suggested that these DBM populations have rapidly developed high levels of resistance to cyantraniliprole and cyclaniliprole. This work provides growers in the region with a recent ranking of insecticide efficacy that documents the loss of control for certain active ingredients, which assists pest managers in the planning of ongoing insecticide rotations for DBM resistance management.

Knowledge of the ecology and behavior of biological control agents is essential for their effective use in biocontrol and Integrated Pest Management (IPM) programs. There is a lack of information regarding the courtship and mating traits that are crucial for successful mating in biocontrol population of coccinellids. To expand our current understanding in this area, 2 coccinellid species commonly used for the biocontrol of soft-bodied insects, Cryptolaemus montrouzieri (Mulsant) and Propylea quatuordecimpunctata (Linnaeus) (Coleoptera: Coccinellidae), were studied. A quantitative analysis was performed to compare their courtship and mating displays. Key behavioral traits of the precopulatory, copulatory, and postcopulatory phases were investigated. The courtship and mating sequences of C. montrouzieri and P. quatuordecimpunctata were similar to each other. During the mating phase, the key displays were the opening of the elytrae and wings followed by body shaking in C. montrouzieri and leg tapping followed by body shaking in P. quatuordecimpunctata. The mating success of both species was not correlated with any courtship display, such as antennal tapping. Only in C. montrouzieri mounting attempt showed a higher frequency from the backside without affecting male mating success. This research adds baseline knowledge about the courtship and mating behavior of the biocontrol population of coccinellids, contributing to the identification of potentially useful benchmarks (e.g., body shaking, leg tapping) for monitoring prolonged mass-rearing processes, thus reducing mating failures.

In central Canada, surveys for the three invasive (Palearctic) Agriotes species-A. obscurus, A. lineatus, and A. sputator-commonly collect A. pubescens, a North American native (Nearctic) click beetle (Coleoptera: Elateridae) that generally co-occurs with Nearctic A. mancus. Despite the abundance of A. pubescens on farmland, its life history and potential economic impact remain largely unknown. Here, we report the identification and field testing of the A. pubescens sex pheromone. We collected headspace volatiles from a single female beetle on Porapak Q, then extracted the female's pheromone gland, and analyzed aliquots of both Porapak extract and pheromone gland extract by gas chromatographic-electroantennographic detection (GC-EAD) and by GC-mass spectrometry. In GC-EAD recordings of gland extract, two esters-geranyl butanoate and geranyl octanoate-elicited antennal responses from A. pubescens males. In a field experiment in Quebec, traps baited with a 1:1 blend of these esters captured approximately 100× more A. pubescens males than traps baited with a single ester. This is the same trap lure used for capturing A. lineatus. In this experiment, and in a similar one run in British Columbia, heterospecific pheromone components added to conspecific pheromone lures reduced captures of A. mancus, A. sputator, A. lineatus, and A. obscurus by 29%, 96%, 44%, and 71%, respectively. These data indicate that, in North America, lures containing pheromone components of multiple Agriotes congeners may not be optimally attractive to all target species.

Previously developed behavioral approaches for controlling the apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), include attract-and-kill (AK) systems such as perimeter trapping using either, odor-baited red sticky spheres or odor-baited, sticky-free attracticidal spheres with contoured tops that ensure the sustained release of both insecticide and feeding stimulant. Here, over a 3-year span in 26 commercial apple orchards across Massachusetts, New Hampshire, and Maine, we evaluated the effectiveness of a novel AK strategy for R. pomonella management. Synthetic apple blend lures were deployed on perimeter-row trees to attract the pest, while perimeter-row insecticide sprays blended with 2% sugar, a known phagostimulant, served as the lethal component. Comparatively, grower standard (GS) blocks received full-block insecticide sprays devoid of sugar and lures. Monitoring revealed that red sticky spheres in AK blocks captured significantly more R. pomonella adults than unbaited monitoring spheres in GS blocks. Penetration of R. pomonella into block interiors remained consistently low and statistically similar for both AK and GS blocks. Whole-block infestation levels showed no significant difference between the 2 management approaches. Notably, insecticide application in AK blocks was reduced by 75%, 64.7%, and 64.2% in 2019, 2020, and 2021, respectively, compared with GS blocks. This grower-friendly AK approach could be integral to a reduced insecticide spray-based strategy for apple cultivation in the northeastern United States.

Thrips (Thysanoptera: Thripidae) can injure seedling cotton (Gossypium hirsutum L.), soybean (Glycine max (L.) Merr.), and peanut (Arachis hypogaea L.) crops in the southern United States. The planting window and timing of thrips infestations into these crops overlap in the region, but thrips preference for oviposition has not been investigated. We evaluated thrips preference for cotton, soybean, and peanut by counting eggs, immatures, and adults at the cotyledon to 4 true leaf stages. Peanut was significantly more attractive for oviposition than cotton and soybean. Oviposition in cotton was significantly higher in the cotyledons than the other leaves. The highest oviposition in soybeans also occurred in the cotyledons but differed only significantly from the fourth true leaf. In all crops, there was no significant difference among oviposition in the true leaves. The highest number of immatures were found on cotton, followed by peanut and then soybean, while adults were evenly distributed among crops. Our results suggest that while peanut is preferred for oviposition, this crop may not facilitate immature development and survival as effectively when compared with cotton. This study presents an initial examination of crop selection by thrips under field conditions and suggests peanut may be the preferred oviposition host.

Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) and Spodoptera exigua Hübner (Lepidoptera: Noctuidae) pose substantial threats to many crops, necessitating the exploration of biopesticides as potential chemical alternatives. One alternative is baculoviruses; however, their instability in the field has hindered their widespread use. Host plant phylloplane affects baculovirus activity at varying levels in different host plants. Formulation contributes significantly to optimizing the baculoviral stability on different phylloplanes against environmental conditions; however, it is expensive and difficult to make in developing or nondeveloped countries. In the current study, we developed a simple tank-mix application (MBF-Tm5) for immediate use, resembling the characteristics of a suspension concentrate formulation for Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). We examined their biological activity against 2nd instar larvae first on an artificial diet under laboratory conditions and on eggplant and pepper phylloplane in greenhouse conditions compared to plain viruses. This formulation exhibited no significant improvement in the biological activity of both viruses on an artificial diet under laboratory conditions but significantly improved the biological activity of both viruses on both plants under greenhouse conditions. The original activity remaining (OAR%) of both unformulated and formulated viruses decreased over time under greenhouse conditions; however, the OAR value of both viruses on eggplants was significantly higher than on pepper plants. Overall, the tank-mix simple formulation of baculoviruses might be a great alternative for improved stability in nature, providing better control.