Research Project: Integrated Insect Pest and Resistance Management on Corn, Cotton, Sorghum, Soybean, and Sweet Potato

Location: Southern Insect Management Research

2020 Annual Report

Objectives
Objective 1: Develop new approaches for the control of noctuid and hemipteran pests of southern row crops, integrating multiple control tactics into integrated pest management systems. Sub-objective 1.A: Develop new strategies that reduce numbers of insecticide applications on soybean and cotton that are not economically justified. Sub-objective 1.B: Develop new approaches for the control of insect pests of sweet potato. Objective 2: Minimize negative effects of integrated pest management systems on pollinators and other beneficial arthropods. Sub-objective 2.A. Determine the impact of current insect management strategies in corn, cotton, sweet potatoes, and soybean on populations of pollinators and beneficial insects. Sub-objective 2.B. Examine the acute toxicity, synergistic/antagonistic interactions, and sub-lethal impacts of commonly used pesticides on honey bees using bioassay, biochemical, and molecular approaches. Objective 3: Improve pest risk assessment by determining environmental influences that affect populations of important insect pests of southern row crops with emphasis on bollworms, tobacco budworms, tarnished plant bugs, stink bugs, and soybean loopers. Objective 4: Develop methods to measure and manage insecticide resistance of pest populations of southern row crops with emphasis on bollworm, tobacco budworm, tarnished plant bug, and stink bugs. Sub-objective 4.A. Measure levels of insecticide susceptibilities of tarnished plant bugs, bollworms and other important insect pests of southern row crops through laboratory bioassays. Sub-objective 4.B. Develop within-field bioassays to determine insecticide susceptibilities of key pests of southern row crops. Sub-objective 4.C. Examine the impact and sensitivity of resistance management options for major insect pests of southern row crops through simulated modeling.

Approach
Insect management guidelines are generally static from year to year regardless of crop prices, costs of insecticides and yield potential of the crop. We plan to summarize published information for bollworm, tarnished plant bug, and stink bugs and develop economic injury level probability distributions using Monte Carlo simulations. On-farm field evaluations across the Mississippi Delta will evaluate economic returns and environmental sustainability of different insecticidal control strategies in soybean and cotton. Commercially available and experimental sweet potato varieties will be planted annually and the economic impact of insect and nematode control in sweet potato will be examined. The impact of current insect management strategies in southern row crops on populations of pollinators and beneficial insects will be examined in production fields. The surrounding habitats of each field will be documented for plant community composition, focusing on blooming plants that may be of interest to pollinators. Each of these fields will be sampled using a combination of sampling techniques. Community structure will be compared between cropping systems, and related to insecticide applications. We plan to evaluate acute and sub-lethal toxicities and synergistic/antagonistic interactions of honey bees to commonly used pesticides. An examination of gene regulation in honey bees associated with immunity, adaptation, detoxification, digestion/metabolism, and stress-related genes will be conducted after exposure to pesticides with techniques such as real-time PCR , RNAseq or microarrays. Hemipteran and lepidopteran phytophagous pest populations are highly mobile within the landscape and use a variety of weeds and crops as host plants. To examine landscape influences on these insects, the landscape composition surrounding historic and current collection locations will be quantified using Cropland Data Layers (CDLs). Using these CDL layers, buffer zones will be generated around locations. Output data will be tabulated to produce total area of habitat type included within each buffer area and will be related to data collected on insect populations using appropriate statistical analyses. SIMRU will continue to examine susceptibilities of hemipteran and lepidopteran insect pests collected from locations across the Mississippi Delta with a variety of assay methods which may include topically treated diet, residual contact bioassays, glass vial bioassays and a feeding contact assays using floral foam. Insects from original collections will be preserved for molecular analysis using genetic markers. When colonies of any of the pest groups have reduced susceptibility to the tested insecticides, efforts will be made to preserve the colony under a selected and non-selected sequence of exposures to the insecticides of interest We propose to develop rapid bioassays to predict the effectiveness of an insecticide application on a real field population of insects. To examine predictive values of laboratory assays on actual field populations, a plot sprayer will be used to deliver a range of formulated product rates on targeted insects.

Progress Report
This is the final report for this project which has been replaced by bridging project #6066-22000-090-00D pending completion of National Program 304 research review. We continued to make collections of native bees in commercial fields of corn, cotton, sorghum, sunflowers, and soybean located across the Mississippi Delta. Additionally, specimens were collected from selected non-agricultural areas including fallow fields, roadside ditches, and National Wildlife Refuges in the Mississippi Delta. Samples were collected with a combination of collection techniques including modified pan traps (bee bowls), malaise traps, and net sampling. Additional specimens were added from bycatch of other studies including moth pheromone traps. Over 50,000 specimens have been cleaned, pinned, and mounted, and entered into a database. Specimens of species new to the state or of significance have been deposited with regional, national, and international entomological museums. This baseline information is being used to examine potential impacts of local agricultural production practices on these insects and compare with production practices and pollinator communities in other regions. Methyl benzoate (MB) is a component of bee semiochemicals. Recent discovery of insecticidal activity of MB against insect pests provides a potential alternative to chemical insecticides. Piperonyl butoxide (PBO, inhibiting P450 oxidases [P450]) significantly synergized MB toxicity in honey bees, indicating P450s are the major MB-detoxification enzymes for bees. Assessing additive/synergistic interactions indicated that MB synergistically or additively aggravated the toxicity of four insecticides (representing four different classes) in honey bees. Data provided from multiple experiments gives us a better understanding of how important the P450s are in detoxifying MB in honey bees. MB could adversely affect feeding and flight in honey bees, and may interact with many conventional insecticides to aggravate toxicity to bees. However, MB is a relatively safe chemical to bees. Proper formulation and optimizing proportion of MB in mixtures may be achievable to enhance efficacy against pests and minimize adverse impact of MB on honey bees. Honey bee workers are known to go through physiological and behavioral changes to differentiate different phenotypes to perform specific duties over their natural lifetime of 6 weeks or longer. Using honey bee workers aged 4- to 42-days old, we examined susceptibility of the bees to five different insecticides from five different classes and measured enzymatic activities of three major detoxification enzymes and an invertase involved in honey production. Results showed gradual increase of natural mortality and decrease of soluble protein content in bees over the age span from 4 days to 42 days. Significant increases of mortality after separate treatments of five different insecticides confirmed drastic age effects of bees over the assessed age span. This study provided evidence of substantial increase of the susceptibility to five insecticides in honey bee workers and emphasized the necessity to use standard bee age to produce quality data in comparative analyses of the risk of pesticides to pollinators. The susceptibilities of field populations of tarnished plant bugs to five different classes of insecticides commonly used in the Mississippi Delta were examined. Insecticides tested included: acephate, permethrin, imidacloprid, thiamethoxam, and sulfoxaflor. These laboratory tests are used to predict field control on cotton and to detect populations that may develop resistance to these insecticides. Additionally, the response of populations of bollworm and tobacco budworm to a diamide insecticide was examined with diet-incorporated bioassay techniques. The susceptibilities have remained constant over the last four years. Artificial diets are commonly used to rear bollworms because they can produce a large number of similarly developed progeny for assays. Notable shortcomings of a meridic diet commonly used to rear bollworms in a laboratory setting were investigated and published. This study demonstrated that larval and pupal fitness were impacted by supplementing meridic diet with cotton leaf tissue. Data from this study will help explain some variability in bioassay results and bridge findings from other assay procedures using plant tissues.

Accomplishments
1. Tarnished plant bug genome project was completed. The tarnished plant bug has developed varying levels of resistance to many of the common insecticides used for its control. The construction of genetic markers through a genome assembly aids in tracking the movement of resistance genes throughout the landscape. ARS researchers in Stoneville, Mississippi, used the tA Hi-C proximity ligation method to generate a high-quality genome assembly of the tarnished plant bug. This genome assembly is approximately 600 Mbp and 6 scaffolds contains 50% of the assembled genome. The genome is currently in annotation phase. This genome can be used to examine genes responsible for resistance development in tarnished plant bug.

Review Publications
Zucchi, M.I., Cordeiro, E., Allen, K.C., Lamana, L.M., Viana, J., Brown, P.J., Omoto, C., Pinheiro, J., Clough, S.J. 2019. Patterns of genome-wide variation, population differentiation and SNP discovery of the red banded stink bug (Piezodorus guildinii). Scientific Reports. 9:14480. https://doi.org/10.1038/s41598-019-50999-z.
Wang, Y., Zhu, Y. 2019. Comparative examination on synergistic toxicities of chlorpyrifos, acephate or tetraconazole mixed with pyrethroid insecticides to honey bees (Apis mellifera). Environmental Science and Pollution Research. 27:6971-6980. https://doi.org/10.1007/s11356-019-07214-3.
Wang, Y., Zhu, Y., Li, W. 2019. Interaction patterns and combined toxic effects of acetamiprid in combination with seven pesticides on honey bee (Apis mellifera L.). Ecotoxicology and Environmental Safety. 190:110100. https://doi.org/10.1016/j.ecoenv.2019.110100.
Li, W., Zhu, Y., Li, F., Cheng, Y., Jin, J., Zhou, Y., He, Y. 2020. In silico discovery of genes encoding insecticide targets and detoxifying enzymes in Brevicoryne brassicae and Lipaphis erysimi. Journal of Asia-Pacific Entomology. 23(1):159-166. https://doi.org/10.1016/j.aspen.2019.12.002.
Zhu, Y., Wang, Y., Portilla, M., Parys, K.A., Li, W. 2019. Risk and toxicity assessment of a potential natural insecticide, methyl benzoate, in honey bees (Apis mellifera L.). Insects. 10:382. https://doi.org/10.3390/insects10110382.
Allen, K.C., Luttrell, R.G., Little, N., Parys, K.A., Perera, O.P. 2019. Response of Bt and non-Bt cottons to high infestations of bollworm (Helicoverpa zea Boddie) and tobacco budworm (Heliothis virescens (F.)) under sprayed and unsprayed conditions. Agronomy. 9(11):759. https://doi.org/10.3390/agronomy9110759.
Briar, S.S., Shrestha, G., Sharma, A., Miller, J.H., Reddy, G.V. 2019. Effect of nitrogen fertilization on flea beetle (Phyllotreta cruciferae) and cabbage seedpod weevil (Ceutorhynchus obstrictus) injury and crop yield in dry land canola. Phytoparasitica. 47:637-645. https://doi.org/10.1007/s12600-019-00762-x.
Shrestha, G., Mettupalli, S., Sharma, A., Gadi, R., Miller, D.A., Reddy, G.V. 2020. Spinosad and mixtures of an entomopathogenic fungus and pyrethrins for control of Sitona lineatus (Coleoptera: Curculionidae) in field peas. Journal of Economic Entomology. 113:669-678. https://doi.org/10.1093/jee/toz348.
Sandhi, R.K., Shapiro Ilan, D.I., Sharma, A., Reddy, G.V. 2020. Efficacy of entomopathogenic nematodes against the sugarbeet wireworm, Limonius californicus (Mannerheim) (Coleoptera: Elateridae). Biological Control. 143. https://doi.org/10.1016/j.biocontrol.2020.104190.
Hiroyoshi, S., Kokwaro, E., Mettupalli, S., Mitsunaga, T., Yagi, S., Reddy, G.V. 2019. Effects of the juvenile hormone mimic NC-184 on the development of the reproductive organs and mating behaviour of nymphs of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae). European Journal of Entomology. 116:477–485. https://doi.org/10.14411/eje.2019.049.
Huang, W., Reddy, G.V., Shi, P., Huang, J., Hu, H., Hu, T. 2019. Allelopathic effects of Cinnamomum septentrionale leaf litter on Eucalyptus grandis saplings. Global Ecology and Conservation. 21:e00872. https://doi.org/10.1016/j.gecco.2019.e00872.
Hiroyoshi, S., Reddy, G.V., Mitsunaga, T. 2020. Effects of photoperiod and aging on the adult spermatogenesis of Polygonia c-aureum (Lepidoptera: Nymphalidae), in relation to adult diapause. Journal of Comparative Physiology. 206:467-475. https://doi.org/10.1007/s00359-020-01413-x.
Fathipour, Y., Maleknia, B., Bagheri, A., Soufbaf, M., Reddy, G.V. 2020. Functional and numerical responses, mutual interference, and resource switching of Amblyseius swirskii on two-spotted spider mite. Biological Control. 146:104266. https://doi.org/10.1016/j.biocontrol.2020.104266.
Parys, K.A., Esquivel, I., Wright, K.W., Griswold, T.L., Brewer, M. 2020. Native pollinators (Hymenoptera: Apoidea) in cotton grown in the Gulf South, United States. Agronomy. 10(5):698. https://doi.org/10.3390/agronomy10050698.
Sharma, A., Jaronski, S., Reddy, G.V. 2019. Impact of granular carriers to improve the efficacy of entomopathogenic fungi against wireworms in spring wheat. Journal of Pest Science. 93:275-290. https://doi.org/10.1007/s10340-019-01161-1.
Gahukar, R., Reddy, G.V. 2019. Management of economically important insect pests of millet. Journal of Integrated Pest Management. 10(1):28. https://doi.org/10.1093/jipm/pmz026.
Zhao, Z., Reddy, G.V., Chen, L., Qin, Y., Li, Z. 2020. The synergy between climate change and transportation activities drives the propagation of an invasive fruit fly in California. Journal of Pest Science. 93:615-625. https://doi.org/10.1007/s10340-019-01183-9.
Sandhi, R.K., Pothula, R., Pothula, S.K., Adams, B.J., Reddy, G.V. 2020. First record of native entomopathogenic nematodes from Montana agroecosystems. Journal of Nematology. 52:1-11. https://doi.org/10.21307/jofnem-2020-060.
Ghaemmaghami, E., Fathipour, Y., Bagheri, A., Talebi, A., Reddy, G.V. 2020. Quality control of the parasitoid wasp Trichogramma brassicae (Hymenoptera: Trichogrammatidae) over 45 generations of rearing on Sitotroga cerealella . Insect Science. 28(1):180-190. https://doi.org/10.1111/1744-7917.12757.
Achhami, B.B., Reddy, G.V., Sherman, J.D., Peterson, R.K., Weaver, D.K. 2020. Effect of precipitation and temperature on larval survival of Cephus cinctus (Hymenoptera: Cephidae) in barley cultivars. Journal of Economic Entomology. 113(4):1982-1989. https://doi.org/10.1093/jee/toaa097.
Sandhi, R., Shapiro-Ilan, D., Reddy, G.V. 2020. Montana native Entomopathogenic Nematode Species against Limonius californicus (Coleoptera: Elateridae). Journal of Economic Entomology. 113:1-8. https://doi.org/10.1093/jee/toaa164.
Guo, X., Reddy, G.V., He, J., Li, J., Shi, P. 2020. Mean-variance relationships of leaf bilateral asymmetry for 35 species of plants and their implications. Global Ecology and Conservation. 23:e01152. https://doi.org/10.1016/j.gecco.2020.e01152.