Research Project: Sustainable Insect Pest Management for Urban Agriculture and Landscapes

Location: Invasive Insect Biocontrol & Behavior Laboratory

2025 Annual Report

Objectives
Objective 1: Discover, characterize, develop and/or promote field adoption of pheromones and other behavior-modifying semiochemicals of key vegetable and fruit insect pests such as cucumber beetles, crucifer flea beetles, stink bugs, squash bugs, and spotted-wing drosophila. Objective 2: Characterize and evaluate native and non-native biological control agents for management of key vegetable pests such as stink bugs, squash bugs, & leaf-footed bugs. Objective 3: Decipher genomes, biochemical and molecular processes of invasive insect pests in order to mitigate damage by crop and landscape pests, such as stink bugs, gypsy moth, and other invasive species. Objective 4: Discover and develop microbial and molecular-based biopesticide agents for control of invasive forest and crop insect pests such as gypsy moth and true bugs, and including model species for evaluation. Objective 5: Utilize molecular approaches to enhance plant defense against destructive insect pests by manipulating the plant defense pathways and insect microflora with a focus on cole crop pests such as those of cabbage and broccoli.

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, urban gardens and landscapes, both organic and non-organic. Biobased 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; (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. Research will also include insect pests that cause major damage to woody plants in the urban landscape. 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 pests in small farms, urban gardens and landscapes.

Progress Report
Objective 1- Cotton seed bug colony and new attractants/repellents. ARS scientists established a cotton seed bug (CSB) colony in containment. A comprehensive study on CSB life cycle, including egg development, metamorphosis, adult mating behavior, adult lifespan, survivorship, as well as attractant and repellents, was conducted. ARS scientists discovered CSB-produced pheromone attractants and repellents. They identified foraging attractants from cotton seeds. These will enable efficient strategies in IPM for timely infestation intervention to protect cotton and agricultural commodities from CSB damage. Striped cucumber beetle pheromone attracts four other vegetable pests. ARS, with scientists from University of California Davis, Virginia Tech and Cornell University showed that striped cucumber beetle male-produced aggregation pheromone is also attractive to four other vegetable pests: spotted cucumber beetle, squash bug, horned squash bug, and western striped cucumber beetle. This allows development and commercialization of tactics useful in cucurbit pest Integrated Pest Management (IPM). Crucifer flea beetle pheromone synthesis and field trapping. Multistate trapping of two crucifer flea beetle species by ARS and scientists from North Dakota State University in and Virginia Tech confirmed compatibility of the two pheromone components, and the added value of commercially available plant attractant, allyl isothiocyanate. Currently, there is no commercial production for either pheromone of these two key pest species in canola and cole crops. ARS chemists made major progress in developing a new synthesis for one pheromone, himachaladiene; development of an efficient synthesis for the 2nd pheromone, hydroxyhimachalanone, continues. Colorado potato beetle (CPB) pheromone discoveries and applications. ARS scientists achieved synthesis of male-produced aggregation pheromone, decemdiol, in quantities useful for field testing. Also, CPB females have a sex pheromone attractive only to males, which showed comparable field attraction, and efforts are underway to identify this sex pheromone(s). ARS and Cornell University scientists undertook field studies on trapping, trap cropping, and other potential control tactics for a push-pull implementation including decemdiol as pull (attractant) and spined soldier bug predator pheromone as push (deterrent) for behavioral control of colonizing CPB. New spotted-wing drosophila (SWD) detection & control tools. ARS scientists developed infestation and population detection tool for SWD (five-component attractive blend). They also developed a push-pull SWD management system, in which the attractant blend was used to pull the SWD away from the orchard; and newly discovered repellent, methyl benzoate, was used to push the SWD out of fruit orchards to protect crops from SWD damage. Methyl benzoate and analogs as repellants and insecticides. ARS scientists developed controlled release formulations (microencapsulation, satchel, cream, and emulsion) of methyl benzoate (MB) and analogs against SWD, bed bugs, ticks, and mosquitoes under lab and field conditions. Several MB analogs were synthesized which exhibited strong spatial/topical repellent properties; most analogs were of low to moderate human toxicity by ingestion or inhalation and were approved by U.S. FDA and EU as food-grade flavor ingredients and preservatives. These are promising as DEET alternatives with high potential as novel topical/spatial repellents against blood-sucking arthropods to enhance disease prevention/control. Effective attractant and traps for leaf-footed bugs. ARS and University of California Riverside scientists tested attractiveness of recently identified and synthesized pheromone, leptotriene, to pest leaf-footed bugs in the genus Leptoglossus. Both males and females of several pest species were strongly attracted, including L. oppositus, but surprisingly not L. phyllopus, a key pest in the Southeast. Studies to understand chemical ecology of this impactful group, and develop the best traps and/or attract-and-kill techniques using the new pheromone, are underway. Objective 2- Biological control of squash bugs and leaf-footed bugs. ARS scientists studied biological control agent Hadronotus pennsylvanicus, a key egg parasitoid of squash bugs (Anasa spp.) and leaf-footed- bugs (Leptoglossus spp.). Seasonal parasitism patterns on squash bug over six years showed no or low parasitism in early season but often high rates during late summer, suggesting augmentative releases in May-June could improve biological control. Studies in Maryland and with New Jersey Dept. of Agriculture will clarify value of parasitoid augmentation to suppress squash bug populations in cucurbits, and role of host pheromones in parasitoid attraction/retention in the field. Objective 3- Genomic and transcriptomic resources for research and surveillance of flighted spongy moth. ARS scientists with Université Laval, Natural Resources Canada Quebec City, Quebec, Canada and University of British Columbia, Vancouver, British Columbia, Canada generated full genomes and conducted comparisons of European and Asian spongy moth subspecies. Forests in northeastern U.S. suffer tremendous damage from spongy moth defoliation. U.S. subspecies have flightless females, though Asian subspecies, known as flighted spongy moth complex, have flighted females and pose a significant invasive threat due to wider distribution and diet. Distinct differences in gene expression between U.S. and flighted populations were identified; these will assist surveillance and identification of invading populations and as spongy moth dsRNA genetic targets. Genetic insight into stink bug pheromone biosynthesis and evolution. ARS and Virginia Tech scientists characterized a family of seven isoprenyl diphosphate synthase-like genes responsible for biosynthesis of pheromones in brown marmorated and related stink bugs as to their gene structures, genomic organization and co-expression patterns with other genes, and evolution of this important pest group. Stink bug genomic insights. Four genome contig assemblies of Pentatomidae were generated by ARS scientists (Ag100 Initiative) including Halyomorpha halys, Murgantia histrionica, and Bagrada hilaris, using PacBio HiFi data generated from a single specimen. A comparative hemipteran genomics project utilizing publicly available genomics data of agriculturally-important hemipterans and anchoring to the newly USDA-sequenced cotton seed bug (Oxycarenus hyalinipennis) genome was performed. Transcriptomic resources for Hemipteran pests including cotton seed bug and bagrada bug. ARS researchers sequenced, assembled, and quantitatively analyzed transcriptomes for multiple life stages of Hemipteran agricultural pests including invasive pests Bagrada hilaris and cotton seed bug, Oxycarenus hyalinipennis. They initiated a comparative transcriptomics study characterizing multi-gene families (e.g., chemosensory receptors and odorant binding proteins) spanning ten hemipteran taxa where numerous differentially expressed genes, including elements implicated in xenobiotic detoxification and insect growth, were identified. Objective 4- Novel entomopathogenic bacteria. ARS scientists discovered a novel species of crystal-forming Bacillus possessing genes for a novel Cry protein family through phylogeny, phenotype, and bioassay activity analyses. Dozens of new bacterial isolates were obtained from environmental sampling, including Chromobacterium and Bacillus strains; phenotypic characterization and insecticidal screening were initiated. ARS and University of Massachusetts, Amherst scientists assessed insecticidal activity through bioassays of all known Chromobacterium species and analyzed genetic loci that may be responsible for toxicity to different orders of insects. Chromobacterium was discovered and licensed for commercial use by ARS, and superior strains could be developed as bioinsecticides. ARS scientists generated high quality genomes for 16 isolates of Bacillus thuringiensis used in a multi-lab NIFA project to identify and develop Bt toxins effective against the Asian citrus psyllid. A number of genes for novel toxins were found. ARS scientists sequenced and characterized a new species of bacterium belonging to the genus Serratia associated with several braconid parasitoids of the olive fruit fly. Discovery and characterization of baculoviruses pathogenic to insect pests. ARS scientists completed 17 genome assemblies for baculoviruses in IIBBL virus collection associated with economically important pests. These include variegated cutworm (pest of fruits and vegetables) and tufted apple bud moth which are typically controlled by chemical insecticides so their viruses have potential as non-chemical pest controls. Genome analysis of a Virginia pine sawfly virus indicated it was a gammabaculovirus species that includes a virus formulated for control of red-headed pine sawfly, suggesting the red-headed pine sawfly virus-based pesticide may be effective for Virginia pine sawfly control. Discoveries of novel gene targets for pest suppression. Candidate novel gene targets for knockdown to induce detrimental effects in a variety of invasive insect pests including Colorado potato beetle, spongy moth, Bagrada hilaris,and others,were identified through comparative analyses of highly regulated transcripts. In vitro transcribed dsRNA targets were tested in vivo by injection and feeding and assayed for mortality and expression of gene targets,with those eliciting the greatest response having potential for being developed for biocontrol use. A metatranscriptomic analysis for spongy moth revealed its response to infection by a panel of diverse microbial pathogens and identified candidate gene targets for knockdown,and spongy moth dsRNAs and antimicrobial peptides were generated.

Accomplishments
1. Combination of pheromone and floral volatile for behavioral control of cucurbit pests. Cucurbit (melon, squash, pumpkin, cucumber, and watermelon) growers must manage multiple damaging pests to their crops. They often rely on broad-spectrum insecticides to protect their crops from insect pests, but these can disrupt beneficial insects, including the essential pollinators of the crop. Behavioral controls, using the insect pests’ own pheromones and other attractants, offer alternative tactics that are very specific to the target pests, to divert pests away from crops to baits or bait stations where they are safely captured or killed. ARS scientists,in Beltsville, Maryland in collaboration with University of California Davis, Virginia Tech, and Purdue University, evaluated which components are key attractants for behavioral control of cucumber beetles, which are key cucurbit pests. They showed that a time-release combination of vittatalactone, the male-produced aggregation pheromone of the striped cucumber beetle, with the inexpensive but strong attractant floral volatile indole, provides effective behavioral control of five pests of cucurbits (striped cucumber beetle, its western sister species, spotted cucumber beetle, squash bug, and horned squash bug), without attracting essential pollinators. This attraction allows development of traps, baits, or other attract-and-kill tactics useful in vegetable integrated pest management (IPM). Researchers, pest managers, extension agents and growers of cucurbit crops will benefit from these new tools for IPM.

2. Cotton seed bug attractant and repellent compounds identified. Cotton seed bug (CSB) is a newly invasive pest to California which is a serious threat to cotton and infests other agricultural and ornamental crops. CSB is a major economic threat to the U.S. cotton industry, which was estimated to cause 15% weight loss in cotton seed, decrease seed germination by up to 88%, and reduce oil seed (the value of cottonseed produced in the U.S. was $1 billion in 2019). Based on host and climate availabilities and lack of natural enemies, CSB has a high likelihood for establishment throughout the southern regions in the U.S. It is urgent and essential to the eradication or management of the cotton seed bug, to discover its pheromone as well as other useful attractants and repellants. ARS scientists in Beltsville, Maryland have now discovered cotton seed bug-produced attractants (seven-component aggregation pheromone; two-component sex pheromone; and four-component oviposition pheromone) and a repellent (one component alarm pheromone) that can be used to monitor and manage CSB. A US Provisional Patent was issued for this technology. This will help scientists and growers to understand the ecology of CSB, and to strategically utilize these semiochemical-based chemicals in an Integrated Pest Management program for timely infestation intervention to protect cotton crops and other agricultural commodities from CSB damage. This will reduce reliance on synthetic pesticides for cotton seed bug management, minimizing environmental impact, and potentially enhancing the effectiveness of other control methods.

Review Publications
Sparks, M., Nelson, D., Harrison, R.L., Larson, N.R., Kuhar, D.J., Haber, A.I., Heraghty, S.D., Rebholz, Z., Tholl, D., Grettenberger, I.M., Weber, D.C., Gundersen, D.E. 2024. Transcriptomic resources for Bagrada hilaris (Burmeister), a widespread invasive pest of Brassicales. PLOS ONE. 19(12):e0310186. https://doi.org/10.1371/journal.pone.0310186.
Harrison, R.L., Francoeur, C.B., Rowley, D.L. 2024. An alphabaculovirus from the zebra caterpillar, Melanchra picta Harris, is an isolate of species Alphabaculovirus maconfiguratae. Journal of Invertebrate Pathology. 207. Article e108220. https://doi.org/10.1016/j.jip.2024.108220.
Sparks, M., Kuhar, D., Weber, D.C., Gundersen, D.E. 2024. A replicated, whole-insect transcriptomic dataset for Nezara viridula (southern green stink bug) spanning developmental stadia and sexes. Data in Brief. 57. Article e111106. https://doi.org/10.1016/j.dib.2024.111106.
Wallingford, A.K., Hernandez, C., Halaweish, F., Osterlund, T., Short, B., Weber, D.C. 2024. Factors influencing Cucurbitacin-E-Glycoside content in bitter hawkesbury watermelon as potential synergist in cucurbit pest management. Horticulturae. 10(11). Article e1182. https://doi.org/10.3390/horticulturae10111182.
Sparks, M., Heraghty, S.D., Kuhar, D.J., Farrar Jr., R.R., Bartholomew, H.P., Blackburn, M.B., Gundersen, D.E. 2025. Larval spongy moth transcriptomic response to ingestion of broad-versus narrow-spectrum insecticidal Chromobacterium species. Scientific Reports. 15. Article e8106. https://doi.org/10.1038/s41598-025-92113-6.
Santos, E., Petersen, J., Santana Duarte, T., Harrison, R.L., Araujo-Ardisson, M. 2025. Alphanudiviral sequences found in transcriptomes of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae). Virus Genes. 61(2025).Article e365–376. https://doi.org/10.1007/s11262-025-02150-6.
Harrison, R.L., Jansen, A.M., Fife, A.N., Rowley, D.L. 2025. The genome sequences of baculoviruses from the tufted apple bud moth, Platynota idaeusalis, reveal recent recombination between an alphabaculovirus and a betabaculovirus from the same host. Viruses. 17. Article e202. https://doi.org/10.3390/v17020202.
Wyckhuys, K., Gu, B., Ben Fekih, I., Finger, R., Kenis, M., Lu, Y., Subramanian, S., Tang, F., Weber, D.C., Zhang, W., Hadi, B. 2024. Restoring functional integrity of the global production ecosystem through biological control. Journal of Environmental Management. 370:(2024)e122446. https://doi.org/10.1016/j.jenvman.2024.122446.
Duan, J.J., Quinn, N.F., Weber, D.C. 2024. Parasitoid-host associations in invaded communities. Current Opinion in Insect Science. 65. https://doi.org/10.1016/j.cois.2024.101250.
Wallingford, A.K., Haber, A., Halaweish, F., Ostlund, T., Weber, D.C. 2025. Multi-component attract-and-kill system for pest insects attacking cucurbit crops. Journal of Economic Entomology. 88 : 112 – 116. https://doi.org/10.1093/jee/toaf172.