Location: Invasive Insect Biocontrol & Behavior Laboratory
2020 Annual Report
Objectives
Objective 1: Identify, synthesize, and develop semiochemicals (pheromones, kairomones, plant volatiles, and other attractants and repellants) of significant insect crop pests (such as harlequin bug, bagrada bug, spotted wing drosophila, striped cucumber beetle, kudzu bug) and their natural enemies for use in integrated pest management.
Subobjective 1a: Develop attractant volatiles and trap designs to monitor and manage the harlequin bug.
Subobjective 1b: Assess known stink bug attractants for value in monitoring and/or managing bagrada bug.
Subobjective 1c: Identify plant volatiles that attract squash bugs.
Subobjective 1d: Identify plant and/or insect volatiles for detection and attraction of kudzu bug.
Subobjective 1e: Improve lures for spotted wing drosophila by identification of fruit-based attractants.
Subobjective 1f: Synthesize and test aggregation pheromone in combination with baits and traps for striped cucumber beetle management.
Objective 2: Develop arthropod biological controls for managing key vegetable pests such as stink bugs, squash bug, and cucumber beetles, including integration of natural enemies with other tactics such as microbial control, semiochemicals, and cultural pest controls.
Subobjective 2a: Evaluate the efficacy of the squash bug natural enemy complex for use in pest management and identify the most effective biological control agents.
Subobjective 2b: Assess the value of native egg parasitoids to suppress BMSB.
Objective 3: Advance effective microbial controls for key crop pests such as stink bugs, noctuid moths, and other seedling pests, including discovery of molecular and ecological mechanisms for sustained field reproduction and persistence, using diverse Bacillus thuringiensis (Bt) strains, Chromobacterium spp., baculoviruses, and other entomopathogens.
Subobjective 3a. Discover additional environmental isolates of C. subtsugae and related species, and characterize their insecticidal properties.
Subobjective 3b. Determine ability of Bt strains to persist in common vegetable mulches.
Subobjective 3c. Develop effective baculoviruses for key pest diamondback moth.
Objective 4: Discover naturally occurring biopesticides (such as botanical compounds and/or RNAis) targeting key vegetable pests such as stink bugs and cucumber beetles.
Objective 5: Determine and strengthen the genetic basis of plant defense mechanisms (e.g., pest aversion and resistance) for protection of high-value crops such as cole crops on small farms or gardens against destructive insects, and determine the influence of the microflora of pest insects and/or plants on the plant defense response.
Subobjective 5a: Determine the effect of knocking out or over-expressing the infestation responsive TF StZFP2 in its native species, and in Arabidopsis.
Subobjective 5b: Determine how infestation inducible Q-type C2H2 TFs affect resistance to pest insects in Arabidopsis and B. oleracea.
Subobjective 5c: Determine the influence of plant and insect microflora on the infestation response of Arabidopsis to T. ni.
Approach
The project brings together a research team with diverse expertise for multiple approaches to insect management. The proposed project will focus on control of key insect pests in small farms and urban gardens, both organic and non-organic. Bio-based integrated pest management approaches to be developed will include: (i) discovery and deployment of natural insect attractants and repellents; (ii) conservation and augmentation of beneficial insects including use of their semiochemicals; (iii) pest-specific microbial controls [bacteria (including Bacillus thuringiensis strains and Chromobacterium spp.) and baculoviruses]; and, (iv) crop genetic resistance using molecular-based gene discovery. Research will target insect pests that cause major damage to key crops such as cucurbits and cole crops, although other important crops such as small fruit, beans, and potatoes may receive attention for specific problems. The combination of semiochemical approaches, biological controls, molecular techniques, and crop resistance, will offer a range of non-chemical tactics useful to integrated pest management strategies for major crop pests in urban small farms and gardens.
Progress Report
Objective 1: Identify, synthesize, and develop semiochemicals (pheromones, kairomones, plant volatiles, and other attractants and repellants) of significant insect crop pests and natural enemies.
ARS scientists in Beltsville, Maryland, continued to develop the controlled-release dispenser for optimization of spotted-winged drosophila (SWD) attraction and application of attract-and-kill strategy to manage SWD populations.
As a result of chemical syntheses initiated by Invasive Insect Biocontrol and Behavior Laboratory (IIBBL), the aggregation pheromones of beetle vegetable pests (striped cucumber beetle, western striped cucumber beetle, crucifer flea beetle, and striped crucifer flea beetle) are now being tested in the field in a total of ten states (Maryland, Virginia, Pennsylvania, New York, Vermont, New Hampshire, Maine, Indiana, North Dakota, California) with university collaborators. In each case, ARS scientists have discovered that plant compounds are very important in enhancing the attraction and feeding of the beetles, making attract-and-kill techniques potentially more effective. Also, for the cucumber beetles, field trials have already shown attraction to other cucurbit pests, an unexpected benefit. Both aggregation pheromones will be deployed together and separate from the plant compounds, to determine the most effective pest management approach for monitoring and possible suppression.
ARS scientists in Beltsville, Maryland, have found that a border trap crop of mustard protected a main crop of collards from its key pest, the harlequin bug, but only if the bordering mustards were separated by two rows rather than adjacent to the main crop. If there was no separation, female harlequin bugs, although they prefer to feed on mustard plants, “commute” to the collards to lay their eggs, thereby defeating the trap crop tactic. Sufficient separation demonstrates that small modifications in trap cropping can make this a valuable tactic for crop protection among small vegetable growers. Addition of the harlequin bug aggregation pheromone, murgantiol, which discoveries in IIBBL made commercially available, may allow further improvement in trap cropping tactics for this key pest.
ARS scientists have confirmed that the superpest Colorado potato beetle (CPB), in addition to possessing a male-produced aggregation pheromone discovered earlier at Beltsville, also have a female-produced pheromone that prompts mate-seeking and mating behavior by males. Further research will attempt to identify and to synthesize this sex pheromone for use in combination with the aggregation pheromone for management of CPB.
Objective 2: Develop arthropod biological controls for managing key vegetable pests.
Flowering borders did not have a significant effect on parasitism by either egg or adult parasitoids of two squash bug species, Anasa tristis and Anasa armigera. Egg parasitism in the early season was significantly lower than egg parasitism in the late season crop; it is likely that the use of augmentative releases early in the season could improve the efficacy of Gryon pennsylvanicum as a biological control agent, especially for the early planting. Further research on the use of augmentative releases is needed.
Measurements taken using transmission electron microscopy determined that the average combined width of the epicuticle and exocuticle of the egg chorion was significantly greater for A. tristis eggs than for A. armigera eggs. This difference may account for the lower rates of parasitism and parasitoid emergence and for the increased time spent drilling into A. tristis eggs compared with A. armigera eggs.
ARS scientists in Beltsville, Maryland, and Newark, Delaware, continued collaboration in identifying volatiles emitted by brown marmorated stink bug (BMSB) that could be used as attractants or repellents for the parasitoid wasp Trissolcus japonicus. Two compounds, tridecane, and (E)-2-decenal, in the BMSB volatiles emission were behaviorally active against this known egg parasitoid. While the former chemical seemed to attract the egg parasitoid, the latter displayed a repellent activity when tested in laboratory bioassay. For brown marmorated stink bug, implementation research is supported by USDA NIFA Specialty Crop Research Initiative (SCRI), Coordinated Agricultural Programs (CAP) grant, “Management of BMSB in U.S. Specialty Crops,” through North Carolina State University in cooperation with several other universities and ARS labs.
Objective 3: Advance effective microbial controls for key crop pests, using diverse Bacillus thuringiensis (Bt) strains, Chromobacterium spp., baculoviruses, and other entomopathogens.
With respect to Objective 3, bioassays were conducted with larvae of a Bacillus thuringiensis (Bt) toxin-resistant strain of diamondback moth to see if simultaneous ingestion of baculovirus and Bt toxin would increase the susceptibility of the larvae to baculovirus infection. With a concentration of Bt toxin that normally kills 100% of wild-type/Bt-susceptible larvae but has no effect on Bt-resistant larvae, no increase was seen in virus-induced mortality compared to a treatment consisting of baculovirus alone. This result indicates that Bt toxin does not increase baculovirus susceptibility in Bt-resistant diamondback moth larvae.
The newly discovered microsporidian pathogen of stink bugs, Nosema maddoxi, appears to have caused catastrophic declines of laboratory colonies of brown marmorated stink bug (BMSB), and possibly to have also caused declines in the field, where it infects BMSB and at least two species of native stink bugs. Its possible value in stink bug management is being investigated under the USDA NIFA Specialty Crop Research Initiative (SPRI) Coordinated Agricultural Projects (CAP) grant, “Management of Brown Marmorated Stink Bug (BMSB) in U.S. Specialty Crops,” through North Carolina State University in cooperation with Cornell University and ARS labs. Research continues as to the host range of this pathogen, which may be useful in suppressing other invasive stink bugs
Objective 4: Discover natural biopesticides (such as botanical compounds and/or RNAi’s) targeting key vegetable pests.
ARS scientists in Beltsville, Maryland, also continued to evaluate methyl benzoate and its analogs as insecticides, with efficacy against bed bugs, mosquitoes, thrips, white flies, nematodes, and some stored product insect pests demonstrated under laboratory conditions. Candidate gene targets for RNAi were identified in squash bug and used to design dsRNAs targeting these genes. Thirteen dsRNAs were and generated and tested against squashbug in preliminary assays. Potential gene targets for dsRNA/RNAi experiments were also identified in bagrada bug.
Objective 5: Determine and strengthen the genetic basis of plant defense mechanisms (e.g., pest aversion and resistance) for protection of high value cole crops.
To study microbes within the pest cabbage looper (CL) that might affect the defense response in Arabidopsis or Brassica, we began by identifying what microbes were found in CL using next generation sequencing to identify the variation in microbes found in different organs of CL that could affect the plant response during infestation. In the first study of its type, we characterized bacteria associated with different digestive tract organs of cabbage looper feeding on collards. They found that the bacteria inhabiting the mandibular glands, Malpighian tubules, and midgut of the caterpillar were broadly similar, but that the bacterial species associated with the salivary glands were substantially different. These results suggest that bacteria inhabiting the salivary glands, and their metabolic products, should be examined separately for their effect on plant defensive responses. Results of those studies may provide methods of interfering with insect countermeasures to plant defenses, reducing damage to crops.
Accomplishments
1. Development of new trapping system for spotted wing drosophila pest management. ARS scientists in Beltsville, Maryland, collaborated with scientist in Towson University, as well as scientists in France, Germany, Spain, and Italy, to develop a dry trap baited with an optimized controlled-release attractant dispenser for spotted wing drosophila (SWD). The new trapping system demonstrated earlier SWD detection compared to the conventional liquid traps that have been currently used in orchards/farms. Due to the simplicity of the dry trap design with controlled release dispenser, it has provided growers/farmers with an efficient, convenient, and easy processing tool for SWD infestation detection and control.
Review Publications
Blassiolli-Moraes, M., Khrimian, A., Michereff, M., Magalhaes, D., Hickel, E., Freitas, T., Barrigossi, A., Laumann, R., Telles, A., Guggilapu, S.D., Silva, C., Sant'Ana, J., Borges, M. 2019. Male-produced sex pheromone of Tibraca limbativentris revisited: absolute configurations of zingiberenol stereoisomers and their influence on chemotaxis behaviour of conspecific females. Journal of Chemical Ecology. 46:1-9.
Boyle, S.M., Weber, D.C., Hough-Goldstein, J., Hoelmer, K.A. 2019. Host kairomones influence searching behavior of Trissolcus japonicus (Hymenoptera: Scelionidae), a parasitoid of Halyomorpha halys (Heteroptera: Pentatomidae). Environmental Entomology. 49(1):15-20. https://doi.org/10.1093/ee/nvz155.
Dos Santos, E.R., Ecker, A., Trentin, L.B., Da Silva, L.A., Borges, M., Ribeiro, B.M., Mowery, J.D., Harrison, R.L., Ardisson-Araujo, D.M. 2019. An iflavirus found in stink bugs (Hemiptera: Pentatomidae) of four different species. Virology. 534:72-79.
Dou, X., Zhang, A., Jurenka, R. 2019. Functional identification of fatty acyl reductases in female pheromone gland and tarsi of the corn earworm, Helicoverpa zea. Insect Biochemistry and Molecular Biology. https://doi.org/10.1016/j.ibmb.2019.103260.
Farrar, R.R., Gundersen, D.E., Kuhar, D.J., Blackburn, M.B. 2020. Insecticidal activity of Chromobacterium phragmitis, a recently described bacterium from tidal marshes. Journal of Entomological Science. 55(1):98-104.
Harrison, R.L., Rowley, D.L., Popham, H.R. 2019. A novel alphabaculovirus from the soybean looper, Chrysodeixis includens, that produces tetrahedral occlusion bodies and encodes two copies of he65. Viruses. 11:579.
Harrison, R.L., Herniou, E.A., Bezier, A., Jehle, J.A., Burand, J.P., Theilmann, D.A., Krell, P.J., Van Oers, M.M., Nakai, M. 2020. ICTV virus taxonomy profile: Nudiviridae. Journal of General Virology. 101:3-4.
Larson, N.R., Strickland, J.A., Shields, V., Zhang, A. 2020. Controlled-release dispenser and dry trap developments for Drosophila suzukii detection. Frontiers in Ecology and Evolution. https://doi.org/10.3389/fevo.2020.00045.
Larson, N., Zhang, A., Feldlaufer, M.F. 2019. Fumigation activities of methyl benzoate and its derivatives against the common bed bug (Hemiptera: cimicidae). Journal of Medical Entomology. https://doi.org/10.1093/jme/tjz138.
Lawrence, S.D., Novak, N.G., Shao, J.Y., Ghosh, S.B., Blackburn, M.B. 2020. Cabbage looper (Trichoplusia ni) salivary glands contain unique bacterial flora in contrast with their alimentary canal, mandibular gland and Malpighian tubules . MicrobiologyOpen. 9(4):e994.
Morrison III, W.R., Larson, N.R., Brabec, D.L., Zhang, A. 2019. Methyl benzoate as a putative alternative, environmentally-friendly fumigant for the control of stored product insects. Journal of Economic Entomology. 112(5):2458-2468. https://doi.org/10.1093/jee/toz179.
Sparks, M., Gundersen, D.E., Bansal, R., Oppert, B.S., Poelchau, M.F., Childers, C., Rhoades, J.H., Velamuri, A.S., Benoit, J.B., Chao, H., Blackburn, M.B., Johnston, J. 2020. Brown marmorated stink bug, Halyomorpha halys (Stål), genome: underpinnings of polyphagy, insecticide resistance potential and biology of a top worldwide pest. BMC Genomics. https://doi.org/10.1186/s12864-020-6510-7.
Su, J., Zhao, B., Zhang, A., Bu, X., Chen, J., Yan, Z., Wang, S. 2019. Pore-ridged nanostructures on the surface of trichoid sensilla of the male Bombyx mori: Aerodynamic trapping, sensing, and transporting of the pheromone molecules. Arthropod Structure and Development. S1467-8039(18)30167-1.
Weber, D.C., Duan, J.J., Haber, A.I. 2020. Male Colorado potato beetles alter search behavior in response to prior female presence on potato plants. Journal of Pest Science. 93:595-604.
Weber, D.C., Morrison III, W.R., Khrimian, A., Rice, K.B., Short, B.D., Herlihy, M.V., Leskey, T.C. 2019. Attractiveness of pheromone components with and without the synergist, methyl (2E,4E,6Z)-decatrienoate, to brown marmorated stink bug, Halyomorpha halys (Stål) [Hemiptera: Pentatomidae]. Journal of Economic Entomology. 113:712-719.
Guo, T., Mehan, S., Gitau, M.W., Wang, Q., Kuczek, T., Flanagan, D.C. 2017. Impact of number of realizations on the suitability of simulated weather data for hydrologic and environmental applications. Stochastic Environmental Research and Risk Assessment (SERRA). 32(8):2405-2421. https://doi.org/10.1007/s00477-017-1498-5.
Blackburn, M.B., Farrar, R.R., Sparks, M., Kuhar, D.J., Mowery, J.D., Mitchell, A.D., Gundersen, D.E. 2019. Chromobacterium phragmitis sp. nov., an insecticidal bacterium isolated from estuarine marshes. International Journal of Systematic and Evolutionary Microbiology. https://doi.org/10.1099/ijsem.0.003508.
