Progress report for LS20-337
Project Information
Managing insects in cucurbit crops is a longstanding challenge due to conflicting needs of intense pest management and strong pollination services. The cucurbit pest complex is notoriously problematic because it includes insects that inflict considerable feeding damage and are also vectors of pathogens that threaten total crop loss. Intense broad-spectrum pesticide use can harm predatory insects and pollinators that are critical for profitable yields. Stronger cultural tools and more selective insecticides are needed to limit pest pressure and conserve ecosystem services by beneficial insects. Colored and reflective mulches are commonly employed to promote plant growth and repel herbivores, but their effects on predator and pollinator attraction are unclear. Likewise, living mulches planted between plastic-mulched rows may buffer the effects of insecticide applications on beneficial insects by providing refuge habitat. However, ecosystem services and potential disservices associated with living mulches in conventionally-managed systems are not well-documented, and for that reason, they are rarely incorporated in conventional vegetable production. To that end, we proposed a research project and a series of experiments manipulating colored mulches, living mulches, and applications of broad spectrum and selective insecticides across three Southeastern states. Our goal is to develop novel cultural tools that better harmonize chemical and biological control, and evaluate their utility in an economic framework that balances risks, costs and benefits in each system. We also demonstrated and deployed these tools by engaging with growers in workshops, field days, and grower conferences across the Southeast.
Objective 1. Determine the effects of colored plastic mulch on the production of cucumber and squash and their pest and beneficial insect communities
Objective 2. Harmonize chemical and biological control in cucurbit systems by integrating plasticulture with living mulches between beds
Objective 3. Assess the impact of augmentative releases of the egg parasitoid Hadronotus pennsylvanicus (formerly Gryon pennsylvanicum) on squash bug populations in squash.
Objective 4. Estimate the economics of different plastic mulch colors, living mulches between beds, and reduced risk pesticides (VA team-Alford)
Cooperators
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Research
Objective 1. Effects of colored plastic mulch on cucurbit production and insect communities.
The agronomic and weed suppression benefits of growing vegetables on plastic mulch are well documented (Decoteau et al. 1986, Lament 1993, Greer and Dole 2003, Andino and Motsenbocker 2004, Frank and Liburd 2005, Gibson et al. 2011). Colored mulches, in particular aluminated (silvery) or reflective mulch, have also been shown to suppress a number of insect pest species (Wolfenbarger and Moore. 1968, Cartwright et al. 1990, Henshaw et al. 1991, Caldwell and Clarke. 1999, Greer and Dole 2003, Nyoike and Liburd. 2010). However, their effects on squash bug, Anasa tristis, are not completely known, and this insect pest can be quite damaging to summer squash in the southeastern U.S.
We conducted small plot replicated experiments in 2020 and 2021 at two locations in Virginia to determine how coloration of plastic mulch affects insect communities (particularly squash bug) and crop yield in zucchini. Four different plastic mulch treatments were used: Black, white, aluminum (reflective), and bare ground. Approximately three weeks after zucchini germination, we sampled for squash bug at weekly intervals. Fruit were harvested over a four-week period.
References Cited:
Andino and Motsenbocker. 2004. Colored plastic mulches influence cucumber beetle populations, vine growth, and yield of watermelon. HortScience. 39:1246-1249.
Caldwell and Clarke. 1999. Repulsion of cucumber beetles in cucumber and squash using aluminum-coated plastic mulch. HortTechnology. 9:247-250.
Cartwright et al. 1990. Influence of crop mulches and row covers on the population dynamics of the squash bug (Heteroptera: Coreidae) on summer squash. J. Econ. Entomol. 83:1988-1993.
Decoteau et al. 1986. Mulch surface color affects yield of fresh-market tomatoes. J. Amer. Soc. Hort. Sci. 114:216-219.
Frank and Liburd. 2005. Effects of living and synthetic mulch on the population dynamics of whiteflies and aphids, their associated natural enemies, and insect transmitted plant diseases in zucchini. Environ. Entomol. 34:857-865.
Gibson et al. 2011. Effect of a living mulch on weed seed banks in tomato. WeedTech. 25:245-251.
Greer and Dole. 2003. Aluminum foil, aluminum-painted, plastic, and degradable mulches increase yields and decrease insect-vectored viral diseases of vegetables. HortTechnology. 13:276-284.
Henshaw et al. 1991. Use of reflective mulches in control of mosaic viruses in summer squash. Natl. Agr. Plastics Congr. Proc. 23:78-83.
Nyoike and Liburd. 2010. Effect of living (buckwheat) and UV reflective mulches with and without imidacloprid on whiteflies, aphids and marketable yields of zucchini squash. Int. J. Pest Manage. 56:31-39.
Wolfenbarger and Moore. 1968. Insect abundances on tomatoes and squash with aluminum and plastic sheetings. J. Econ. Entomol. 61:34-36.
Objective 2. Harmonize chemical and biological control in cucurbit systems by integrating plasticulture with living mulches between beds
Agricultural intensification and pesticide use often come at a cost of ecosystem services delivered by beneficial insects. However, re-integrating diverse and structurally complex non-crop habitat may provide food and refuge resources that mitigate non-target effects on natural enemies and enable rapid recolonization of pesticide-treated crop areas, harmonizing chemical and biological control. Here, we manipulate pesticide treatments and living between rows of zucchini crops across four replicated experiments in Georgia, North Carolina, and Virginia, to determine how refuge habitat moderates non-target effects on natural enemies. The experiment was established in 2021 at four locations: Virginia Tech Eastern Shore AREC in Painter, VA; Homefield Farm in Whitethorne, VA; MHCR&EC in Mills River, NC, and Durham Horticultural Research Farm, Athens, GA; to assess the effect of a living mulch plant mixture of teff grass, buckwheat and red clover sown between plastic-mulched rows compared to bare ground between plastic beds on the insect pest and beneficial community in a squash production agroecosystem. We assessed each mulch treatment under routine insecticide applications versus no insecticides. We predicted that a buckwheat, clover, teff grass living mulch will provide habitat resources that can buffer effects of insecticide treatments on beneficial insects (Hooks et al. 1998, Lee et al. 2001, Frank and Liburd 2005). Therefore, we hypothesized that pest pressure would be lowest in living mulch treatments.
References cited:
Frank and Liburd. 2005. Effects of living and synthetic mulch on the population dynamics of whiteflies and aphids, their associated natural enemies, and insect transmitted plant diseases in zucchini. Environ. Entomol. 34:857-865.
Guner, N., Pesic-VanEsbroeck, Z., Rivera-Burgos, L. A., & Wehner, T. C. (2019). Screening for Resistance to Zucchini yellow mosaic virus in the Watermelon Germplasm. HortScience, 54(2), 206–211. https://doi.org/10.21273/HORTSCI13325-18
Hooks, C. R. R., Valenzuela, H. R., & Defrank, J. (1998). Incidence of pests and arthropod natural enemies in zucchini grown with living mulches. Agriculture, Ecosystems & Environment, 69(3), 217–231. https://doi.org/10.1016/S0167-8809(98)00110-8
Lee et al. 2001. Refuge habitats modify impact of insecticide disturbance on carabid beetle communities. J. Appl. Ecol. 38:472-483.
Objective 3. Assess the impact of augmentative releases of the egg parasitoid Hadronotus pennsylvanicus (formerly Gryon pennsylvanicum) on squash bug populations in squash.
Biological control of squash bugs is largely understudied, specifically the potential of its egg parasitoid, Hadronotus pennsylvanicus (Hymenoptera: Scelionidae), as an augmentative biological control agent.
Squash bug and egg parasitoid Gryon pennsylvanicum (Fig. 1) lab colonies were established from wild collected individuals in Whitethorne, VA during the 2019 field season. From August 2019 to August 2022, G. pennsylvanicum populations were reared on squash bug eggs and lab parasitism data were collected. Our lab rearing data focused on the wasp’s parasitism rates, progeny sex ratio, and development time (i.e., number of days from parasitism to emergence). These data were pivotal to determine how many parasitized eggs would need to be deployed at each release site in order to achieve a release rate of about 2-3 female wasps per plant.
For this reason, we performed field releases of H. pennsylvanicus on organic farms in Virginia as well as North Carolina and Georgia to test whether A. tristis egg parasitism would improve at parasitoid release sites. We chose organic farms growing summer squash as release sites and paired each site with a no-release site where no parasitoids were released. Parasitoids were reared in the lab and deployed as parasitized squash bug egg masses at a rate of 2-3 females wasps per plant in June 2020 and 2021. Following H. pennsylvanicus deployment, biweekly collections of squash bug eggs were conducted at release and non-release sites.
Objective 3b (Impacts of insecticides on squash bug and its parasitoid Hadronotus pennsylvanicus).
Growers can control squash bug by applying insecticides such as pyrethroids or neonicotinoids (Doughty et al. 2016). While these insecticides are effective in controlling squash bug (Eiben et al. 2004, Abney and Davila 2011, Doughty et al. 2016), they can have negative side effects on non-target organisms including pollinators and arthropod natural enemies (Smith and Stratton 1986, Slosser et al. 1989, Kilpatrick et al. 2005, Desneux et al. 2007). Thus, there is impetus for reduced risk alternatives to pyrethroids and neonicotinoids for control of squash bug.
Here we evaluated several reduced risk insecticides and one broad spectrum insecticide for their toxicity to A. tristis nymphs as well as Hadronotus pennsylvanicus (formerly Gryon pennsylvanicum) (Ashmead) (Hymenoptera: Scelionidae), a key parasitoid of squash bug. Treatments (Table 1) included the neonicotinoid acetamiprid (IRAC 2016, Group 4A), which has a lower toxicity to pollinators compared to other neonicotinoids (Decourtye and Devillers 2010); sulfoxaflor (IRAC 2016, Group 4C) and flupyradifurone (IRAC 2016, Group 4D), of which both act on the nicotinic acetylcholine receptor (Casida and Durkin 2013); three compounds pyrifluquinazon (IRAC 2016, Group 9), afidopyropen (IRAC 2016, Group 9D), and flonicamid (IRAC 2016, Group 29), which act on the chordotonal organ impacting the ability of hemipterans to feed (Morita et al. 2007; Nesterov et al. 2015)); and finally cyclaniliprole a broadspectrum diamide (IRAC 2016, Group 28). With the exception of cyclaniliprole, most of the aforementioned insecticides are generally used to target sucking hemipterans such as aphids, psyllids, and whiteflies, but which thorough information is lacking on their efficacy against squash bug. The pyrethroid, λ-cyhalothrin was tested as a commercial standard.
References cited
Abney, M. R., and R. Davila. 2011. Evaluation of foliar and soil applied insecticides for control of squash bug on zucchini squash, 2010. Arthrop. Manag. Tests 36 (1): E68 (DOI: http://dx.doi.org/10.4182/amt.2011.E68)
Casida, J. E., and K. A. Durkin. 2013. Neuroactive insecticides: targets, selectivity, resistance, and secondary effects. Annu. Rev. Entomol. 58: 99-117.
Chapman, A., T. Kuhar, P. Schultz, T. Leslie, S. Fleischer, G. Dively, and J. Whalen. 2009. Integrating Chemical and Biological Control of European Corn Borer in Bell Pepper. J. Econ. Entomol. 102: 287-295.
Decourtye, A. and J. Devillers. 2010. Ecotoxicity of neonicotinoid insecticides to bees. In: Thany, S.H. (ed) Insect Nicotinic Acetylcholine Receptors. Advances in Experimental Medicine and Biology, vol 683. Springer, New York, NY, pp 85–95. https://doi.org/10.1007/978-1-4419-6445-8_8
Desneux N, A. Decourtye, and J. M. Delpuech 2007. The sublethal effects of pesticides on beneficial arthropods. Annu. Rev. Entomol. 52: 81–106.
Doughty, H. B., J. M. Wilson, P. B. Schultz, and T. P. Kuhar. 2016. Squash bug (Hemiptera: Coreidae): biology and management in cucurbitaceous crops. J. Integr. Pest Manag. 7: 1.
Eiben, J., C. Mackey, W. Roberts, and J. V. Edelson. 2004. Foliar applied insecticides for controlling squash bug, 2003. Arthrop. Manag. Tests 29 (1): E74 (DOI: http://dx.doi.org/10.1093/amt/29.1.E74)
Fairbrother, A., J. Purdy, T. Anderson, and R. Fell. 2014. Risks of neonicotinoid insecticides to honeybees. Environ. Tox. Chem. / SETAC 33: 719-731.
Fargo, W. S., P. E. Rensner, E. L. Bonjour, and T. L. Wagner. 1988. Population dynamics in the squash bug (Heteroptera: Coreidae) squash plant (Cucurbitales: Cucurbitaceae) system in Oklahoma. J. Econ. Entomol. 81: 1073-1079.
Kilpatrick, A. L., A. M. Hagerty, S. G. Turnipseed, M. J. Sullivan, and W. C. J. Bridges. 2005. Activity of selected neonicotinoids and dicrotophos on nontarget arthropods in cotton: Implications in Insect Management. J. Econ. Entomol. 98: 814-820.
Kuhar, T. P., J. Speese, R. J. Cordero and V. M. Barlow. 2005. Evaluation of insecticides in pumpkins, 2004. Arthrop. Manag. Tests 30: E70.
Kuhar, T. P., and H. Doughty. 2016. Evaluation of Foliar and Soil Insecticides for the Control of Foliar Insects in Summer Squash in Virginia, 2015. Arthropod Management Tests 41: tsw023.
Morita, M., T. Ueda, T. Yoneda, T. Koyanagi, and T. Haga. 2007. Flonicamid, a novel insecticide with a rapid inhibitory effect on aphid feeding. Pest Manag. Sci. 63: 969-973.
Nauen, R., P. Jeschke, R. Velten, M. E. Beck, U. Ebbinghaus-Kintscher, W. Thielert, K. W⍤lfel, M. Haas, K. Kunz, and G. Raupach. 2015. Flupyradifurone; a brief profile of a new butenolide insecticide. Pest Manag. Sci. 71: 850-862.
Neal, J. J. 1993. Xylem transport interruption by Anasa tristis feeding causes Cucurbita pepo to wilt. Entomol. Exp. Appl. 69: 195-200.
Nesterov, A., C. Spalthoff, R. Kandasamy, R. Katana, N. B. Rankl, M. Andres, P. Jahde, J. A. Dorsch, L. F. Stam, F. J. Braun, B. Warren, V. L. Salgado, and M. C. Gopfert. 2015. TRP channels in insect stretch receptors as insecticide targets. Neuron 86: 665-671.
Pisa, L. W., V. Amaral-Rogers, L. P. Belzunces, J. M. Bonmatin, C. A. Downs, D. Goulson, D. P. Kreutzweiser, C. Krupke, M. Liess, M. McField, C. A. Morrissey, D. A. Noome, J. Settele, N. Simon-Delso, J. D. Stark, J. P. Van der Sluijs, H. Van Dyck, and M. Wiemers. 2014. Effects of neonicotinoids and fipronil on non-target invertebrates. Environ. Sci. Poll. Res. Int. 22: 68-102.
Slosser, E., W. E. Pinchak, and D. R. Rummel. 1989. A review of known and potential factors affecting the population dynamics of the cotton aphid. Southwest. Entomol. 14: 302-313.
Smith, T. M. and G. W. Stratton. 1986. Effects of synthetic pyrethroid insecticides on nontarget organisms. Residue Reviews: Reviews of Environmental Contamination and Toxicology: 93-120.
Wyenandt, A., T. P. Kuhar, G. C. Hamilton, M. J. VanGessel, E. Sanchez, and D. Dugan. 2016. 2016 Mid-Atlantic commercial vegetable production recommendations. Virginia Cooperative Extension. Publication #456-420
Objective 1. Effects of colored plastic mulch on cucurbit production and insect communities.
The most abundant pest in the study by far was squash bug, Anasa tristis, and, in both years, squash bug adults and egg masses were more numerous on zucchini plants grown in white and reflective plastic mulch compared to bare ground plants. Greater nymphal densities and marketable fruit yield were observed in certain plastic mulch treatments versus the bare ground treatment, yet these differences were not consistent in both years. Contrary to the repellency effects reflective mulches have on other cucurbit insect pests, our research suggests that reflective and other plastic mulch colors can negatively impact squash bug management, especially in regions with high squash bug pressure. From a crop yield standpoint, zucchini plants in black and reflective mulches produced about twice as many marketable zucchini as bare ground plants in 2019. However, there was no effect of mulch treatment on crop yield in 2020.
Discussion - Our research showed similar results as others with black and silvery reflective mulches having a beneficial impact on squash yield compared to bare ground beds in one of the years. The reasons for these differences are not completely known, but are likely related to increased soil temperature and moisture retention resulting in greater plant growth and productivity. However, greater densities of squash bugs were found on plastic mulch plots compared to bare ground beds. Squash bug adults like to seek shelter in the planting hole of plastic mulch and consequently may deposit more eggs on those plants. Our study offers new insights for cucurbit growers to use when considering whether they should implement plasticulture in their growing systems.
Publication produced:
Boyle, S. M., A. M. Alford, K. C. McIntyre, D. C. Weber, and T. P. Kuhar. 2022. Effect of plastic mulch colors on Anasa tristis (Hemiptera: Coreidae) population dynamics in summer squash (Cucurbita pepo). J. Econ. Entomol. 115(3): 808–813. https://doi.org/10.1093/jee/toac036
Objective 2. Harmonize chemical and biological control in cucurbit systems by integrating plasticulture with living mulches between beds
Surprisingly, we found fewer natural enemies in living mulch plots and limited evidence that natural enemy activity was affected by organic pesticides in our plots generally. Living mulch and pesticide treatments had differential direct effects across pest taxa. Pesticides had no effect on spotted and striped cucumber beetles, while living mulches directly reduced them by 25%. Conversely, pesticides reduced squash bug pressure by 50%, while living mulches had no effect. Although crops were grown in plastic mulch which partially protected them from competition, living mulches sharply reduced zucchini yields at sites where living mulches were unmanaged, and had no effect on yields at sites where mulches were mowed monthly, suggesting that living mulches require investments in management to minimize competition with crops. All together, these results suggest that while non-crop plant diversity has clear benefits for natural pest suppression in many systems, these benefits cannot be generalized across all taxa, and particularly in crops like zucchini which themselves provide abundant floral resources. All data from these experiments have been analyzed and visualized, and results were presented in 2022 at the International IPM symposium. We also published one review article (Huss, Holmes, and Blubaugh 2022) on the risks and benefits of living mulch intercrops in the Journal of Economic Entomology.
Publication:
Huss, C.P. , K.D. Holmes, and C.K. Blubaugh. 2022. Benefits and risks of intercropping for crop resilience and pest management. Journal of Economic Entomology. toac045, https://doi.org/10.1093/jee/toac045
Symposium Presentation:
Blubaugh, C., A. Stawara, T. Kuhar, J. Walgenbach, T. Bilbo, H. Doughty, L. Lopez, C. Walls, S. Boyle, A. Alford. 2022. Can living mulches buffer natural enemies from non-target effects of pesticides? IPM 2022: 10TH INTERNATIONAL IPM SYMPOSIUM, February 28–March 3, 2022, Denver, Colorado.
Objective 3. Assess the impact of augmentative releases of the egg parasitoid Hadronotus pennsylvanicus (formerly Gryon pennsylvanicum) on squash bug populations in squash.
In both years, we found greater parasitism rates of A. tristis eggs collected at Virginia release sites compared to no-release sites. While all eggs collected at release and no-release sites before parasitoid deployment displayed low levels of H. pennsylvanicus parasitism, eggs from release sites were significantly more parasitized than eggs from no-release sites within two weeks post-deployment.
Table: Ratio of parasitized: unparasitized A. tristis egg masses collected at each release and no-release site in 2020. Combined ratios (bold values) were compared between release and no release treatments (Fishers Exact Test of Independence). Asterisks indicate significantly larger parasitized: unparasitized egg mass ratio (*P < 0.01, *** P < 0.0001) per sample date.
Our two-year study demonstrates that the releases of lab-reared H. pennsylvanicus can increase A. tristis egg parasitism rates and subsequently decrease successful nymph hatch rates in early summer squash plantings.
Objective 3b (Impacts of insecticides on squash bug and its parasitoid Hadronotus pennsylvanicus).
Pyrethroids or neonicotinoids have been the insecticides of choice for chemical control of squash bug for the past three decades (Doughty et al. 2016, Wyenandt et al. 2016). Although these insecticides are efficacious at controlling squash bug nymphs (Eiben et al. 2004, Kuhar et al. 2005, Abney and Davila 2011, Kuhar and Doughty 2016), most are also toxic to non-target arthropods and are generally not compatible with IPM or pollinator protection plans (Smith and Stratton 1986, Fairbrother et al. 2014, Pisa et al. 2014). In this study, acetamiprid, lambda-cyhalothrin, sulfoxaflor, and flupyradifurone all provided effective control of squash bug nymphs in lab bioassays. These insecticides have also resulted in significant reductions in squash bug densities in field experiments (Kuhar and Doughty 2016).
Acetamiprid, sulfoxaflor, and flupyradifurone are considered less toxic to pollinators than pyrethroids, while also providing control of aphids, whiteflies, and other small piercing-sucking pests. Repeated applications of pyrethroids, on the other hand, often lead to outbreaks of aphids by suppressing natural enemy abundance and promoting insecticide resistance (Slosser et al. 1989, Chapman et al. 2009).
With regards to insecticide impact on the parasitoid H. pennsylvanicus, lambda-cyhalothrin and sulfoxaflor caused the highest mortality of adult wasps compared to flupyradifurone, pyrifluquinazon, and flonicamid. High rates of H. pennsylvanicus mortality in the lambda-cyhalothrin treatment was not surprising, as lethal and non-lethal effects have been observed with other scelionid egg parasitoid species (Salerno et al. 2002, Bayram et al. 2010). It was surprising to observe high mortality rates for adult parasitoids exposed to sulfloxaflor since it is absorbed systemically by plant tissues and acts on sucking pests that imbibe the compound when feeding on treated plant fluids (Sparks et al. 2013). The H. pennsylvanicus adults were exposed to all treatments via contact by walking on treated filter papers. There is recent evidence that supports this result, as detrimental effects of contact exposure to sulfoxaflor were found with three distinct Trichogramma parasitoid species (Jiang et al. 2019). Future research should add field-related complexity to laboratory assays, such as different insecticide application methods for whole C. pepo plants (e.g., foliar, chemigation, seed treatments), to elucidate more realistic insecticide exposure effects on H. pennsylvanicus adults.
Based on our bioassays, flupyradifurone was the only reduced risk insecticide found to be both highly toxic to A. tristis nymphs and nontoxic to H. pennsylvanicus adults. Our laboratory bioassays align with results from field trials displaying significant reductions in A. tristis abundance on summer squash plants sprayed with flupyradifurone (Kuhar and Doughty 2018). Although no previous research has studied the effects of flupyradifurone exposure on scelionid parasitoids, Tabebordbar et al. 2020 showed that parasitoid Trichogramma evanescens has reduced lethal and sub-lethal effects from contact exposure to field rates of the flupyradifurone compared to pyrethroid deltamethrin exposure. Additional studies are needed to identify if there are sub-lethal behavioral and life history effects of insecticide exposure on H. pennsylvanicus. In particular, research focused on determining potential effects on H. pennsylvanicus ability to successfully search for and locate A. tristis egg masses, as well as on parasitoid fecundity and longevity, would provide valuable information concerning the overall risk broad and narrow spectrum insecticides pose to H. pennsylvanicus.
Education
Three graduate students are being trained under this grant project:
Ph.D. student, Sean Boyle, Department of Entomology, Virginia Tech - began his program in 2019.
M.S. student, Courtney Walls, Department of Entomology, Virginia Tech - began her program in 2020.
M.S. student, Allison Stawara, Department of Entomology, University of Georgia - began her program in 2021.
Educational & Outreach Activities
Participation Summary:
Wilson, James M.; Day, Eric; Kuhar, Thomas P. 2000. Striped Cucumber Beetle. Virginia Cooperative Extension Publication No. AEE-72. https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ENTO/ENTO-61/ENTO-61-pdf.pdf
Presentations:
Boyle, Sean, Thomas Kuhar, and Donald Weber. 2000. Reevaluating thresholds for squash bug, Anasa tristis, life stages in summer squash (Cucurbita pepo) systems2020 Entomology Virtual Meeting: Annual Meeting of the Entomological Society of America, November 11-25, 2020, Orlando, FL - Virtual.
Walls, Courtney, James Wilson, and Thomas Kuhar. 2020. What’s the buzz in Virginia cucurbits: Three trapping methods to survey pollinators. 2020 Entomology Virtual Meeting: Annual Meeting of the Entomological Society of America, November 11-25, 2020, Orlando, FL - Virtual.
Walls, Courtney. 2020. Beekeepers at Virginia Tech Virtual Meeting,– “Pollinators you can find in Virginia Cucurbits” October 27, 2020 – Virtual - Attendance: 25
Walls, Courtney, James Wilson, and Thomas Kuhar. 2021. Virginia Pumpkin Growers Association– “ What we found in Virginia Pumpkins” February 9, 2021- Virtual - Attendance: 30
Walls, Courtney. 2021. "Ask an Entomologist Virtual Field Trip", North Wilkes Middle School (Wilkes Country Schools, NC),– “Bees around you” – March 18, 2021 -Virtual -Audience: 100+
Kuhar, T. 2000. Insect pest update. Cucurbit Crops Session: Southeast Virginia Fruit and Vegetable Conference, Chesapeake, VA, Feb 27, 2000.
Kuhar, T. 2000. Vegetable pest IPM info in virtual Zoom Meeting on Vegetable Gardening Resources – VCE, Virginia Beach, VA, March 27 – 40 people
Kuhar, T. 2000. Vegetable IPM update. VCE Ag Today meeting focused on vegetable production, May 7 – 40 people
Kuhar, T. 2000. Insect pest control. IPM Ask the Expert – Teleconference, Radio show – Mid-Atlantic U.S., May 27 – 50 people
Kuhar, T. P. and D. Owens. 2020. Seasonal Insect Management for Vegetable Crops: Protecting Beneficial Insects While Minimizing Insect That Damage Vegetable Crops. 2020 Virtual Vegetable Grower Meetings, Virginia Coop. Ext., June 24, 2020.
Kuhar, T. 2000. Vegetable IPM update. Northern Virginia Virtual Vegetable Meeting, June 24, 40 people
Kuhar, T. P. 2020. Update on insect management. LATE SEASON Virtual PUMPKIN MEETING, Virginia Pumpkin Growers Association, S E P T EMB E R 1 6, 2020.
Kuhar, T. P. 2020. Fall Vegetable Pest Updates, VCE AG Today Virtual Meeting, October, 29, 2020.
Kuhar, T. P. 2020. Fall Vegetable Pest Updates, Shenandoah Valley Vegetable Grower Virtual Meeting, October, 29, 2020.
Kuhar, Thomas. 2020. Pest Management Update for Cucurbits. Northern Neck Vegetable Growers Association Meeting, Virtual. https://bit.ly/2020NNVGACucurbits
Kuhar, T., J. Wilson, and C. Walls. 2021. Insect control and pollinators. Virginia Pumpkin Growers Association 2021 Annual Meetings. Virtual. Hillsville, VA. Feb 9, 2021.
Virginia Biological Farming Virtual Conference. March 18, 2021
Kuhar, T. 2001. Organic options for battling insect pests. Organic Production Agent In-service Training. Roanoke, VA. March 24 & 25, 2021. Virtual.
Kuhar, T. 2021. Managing insect pests. Vegetable Crop Production for Urban Agriculture. Virginia Cooperative Extension In-Service Agent Training, March 2 and 3, 2021. Virtual.
Alford, A. 2020. Demonstrated colored mulch research plots. Southwest Minnesota State University Field Day. Marshall, MN. Aug 5, 2020.
Alford, A. 2020. Rotary club presentation of the experimental system/results of 2020 study. Marshall, MN. Oct 23rd 2020.
Learning Outcomes
Project Outcomes
After evaluating squash and cucumbers grown on four different mulch treatments (silver reflective, white plastic, black plastic, bare ground) at two locations in 2019 and three locations in 2020, we found a significant effect of mulch treatment on yield of squash and cucumbers with black and silvery reflective mulch tending to yield significantly more fruit. However, greater densities of squash bugs were found on the plastic mulch plots compared with bare ground. These results suggest that in addition to aiding in weed suppression, colored plastic mulches positively impact crop yield of cucurbits, but also may result in greater squash bug populations. This information can aid in the decision making for growers to invest in the cost of plastic mulch for their cucurbit production.
In another experiment, the squash bug parasioid, Gryon pennsylvanicum was reared in Blacksburg Virginia and augmentative releases were made on two farms in eastern Virginia, while two nearby farms included as non-release controls. Parasitism of squash bug egg masses was increased significantly at the release sites. While more data are needed, these results are promising for the potential to enhance biological control of squash bug.
Cucurbit Growers impacted by project:
Green Hearts project urban farm rachel@greenheartsc.org Rachel Meek
Rooting Down Farms harlestontowles3@gmail.com Harleston Towles
Joseph Fields Farm josephfieldsf@gmail.com Joseph Fields
Crescent Farms crescentfarmsc@gmail.com Margie Levine and Holly Welch
Elysian Fields elysianfieldsfarmnc@gmail.com Elise Bortz
Seeds thyde@seedsnc.org Trevor Hyde
Somerset somersetfarmcsa@gmail.com Olly & Frederick
Perry-Winkle Farm perrywinklefarm@aol.com Cathy Jones
Flow Farm mark@flowtrading.com Mark Epstein
New Ground ccclock59@yahoo.com, dogdog54@yahoo.com Millard and Connie Locklear
Agroecology Education farm alison_reeves@ncsu.edu Alison Reves, Michelle Schroeder-Moreno
Hilltop farms info@hilltopfarms.org Fred Miller
Infinity Hundred Farms info@infinityhundred.com David McConnell
Raleigh City Farm info@raleighcityfarm.org Lisa Grele Barrie
Three Porch Farm 3porchfarm@gmail.com
Woodland Gardens farm@woodlandgardensorganic.com Celia Barss
Farm in the Wildwood farminthewildwood@gmail.com Danielle Pereira
In 2021, we will embark on objective 2 of the grant where we will be assessing the effects of living mulch between the row beds of squash. The living mulch will include a mix of teff grass to suppress weeds and buckwheat and red clover to provide floral resources for natural enemies and pollinators. The experiment will be conducted in Georgia, North Carolina, Minnesota, and two locations in Virginia. We will assess the effects of the living mulch treatment with and without insecticide applications on populations of insect pests, natural enemies, and pollinators. Yield of squash will also be assessed.