- Agronomic: corn
- Education and Training: extension, on-farm/ranch research
- Pest Management: biological control
Over the past decade grubs of the Asiatic garden beetle (Fig. 1A), Maladera castanea Arrow (Coleoptera: Scarabaeidae: Melolonthinae), which will be referred to as AGB for the rest of this report, have emerged as an early season subterranean root feeding pest of corn in Indiana (Krupke et al. 2007), Michigan (DiFonzo 2007), Ohio (Hammond 2013), and to a lesser extent Virginia (Tiwari et al. 2008). AGB was initially introduced to the United States in New Jersey in 1921 and would eventually cause sporadic economic damage to turf and ornamentals (Hallock 1936). AGB has since spread to at least 24 states and 2 Canadian provinces (Eckman 2015). The first report of AGB in Ohio occurred around 1960 (CABI 1961), and by 2012 the grubs were first observed heavily infesting corn (Figs. 1B-E) in sandy soils (Fig. 1F) in the northwestern counties (Hammond 2013). There are currently no successful management tactics or rescue treatments available for management of AGB in corn (Richer and Michel 2014), often leaving farmers to replant (at great expense) should infestations become too severe.
Entomopathogenic (insect-killing) nematodes (EPNs) are naturally occurring in the environment and could be a sustainable control agent for use against AGB in corn (Rasmann et al. 2005; Kergunteuil et al. 2016); commercial nematodes are successful for AGB management in turfgrass (Tashiro 1987; Morales-Rodriguez et al. 2010). Recent advancements in rearing techniques and easy-to-use formulations have lowered production costs which has made it feasible to work with locally isolated nematodes (Testa and Shields 2017) instead of commercially purchased one that are accustomed to laboratory conditions and not environmental extremes. Benefits of local nematodes compared to commercially available nematodes are that they are better adapted to local environmental extremes, can persist longer in the absence of insect hosts (Shields et al. 2009), and are cheaper to mass produce and apply from modified spray equipment (Lacey and Georgis 2012).
The goal of this research was to assess AGB susceptibility to locally isolated EPNs in Ohio field corn and understand the spatial distribution of EPN in agroecosystems. To accomplish this, EPN were isolated from the soil samples collected at farms affected by AGB in northern Ohio during 2018 and 2019 and they were evaluated in the greenhouse for efficacy against AGB grubs. Isolated nematodes were subsequently be mass reared “in vivo” using economical and low input technologies. Local AGB populations will be collected from local farms and evaluated for susceptibility to these nematode species in greenhouse and field trials. Field sampling data were analyzed to identify trends in spatial distribution over time. The results from this research will help develop a sustainable management plant for AGB in corn using EPN.
This proposal includes an outreach component to educate farmers about the safety and persistence of these nematode species, and to provide demonstrations regarding rearing nematodes at home and applying them with modified spray equipment. Findings from this research have been presented at annual AGB meetings held in Wauseon, OH in March 2019 and February 2020, and an extension handout that educates readers on the life cycle and utility of EPN with respect the AGB, how to isolate, extract, mass-rear, and apply EPN for AGB control, and other important pieces of information. Contingency plans have been devised for the research portion of this study, while extension events including talks and workshops will be evaluated pre- and post-workshop surveys.
Additional EPN assessments beyond the grant period will be conducted in 2020 and 2021. EPN isolated from 2018 and 2019 will be evaluated for efficacy against AGB in sand and loam soils placed in microplots in the field at the Ohio Agricultural Research and Development Center’s Snyder Farm in Wooster, OH. Additionally, efforts to DNA barcode isolated EPN species from 2018 and 2019 are ongoing and will be used to confirm identification of the collected species and produce a phylogenetic estimation to assess population structure in northern Ohio farms. These findings will be included in a comprehensive peer-reviewed manuscript to be published in the Journal of Nematology.
(CABI) CAB International. 1961. Maladera castanea. Distribution maps of plant pests, Map 121. (http://www.cabi.org/dmpp/default.aspx?site=164&page=1060).
DiFonzo, C. 2007. Asiatic garden beetle in southern Michigan. Michigan State University Extension. Accessed March 20, 2017. http://msue.anr.msu.edu/news/asiatic_garden_beetle_in_southern_michigan
Eckman, L. 2015. Host plant feeding preferences of the adult Asiatic garden beetle, Maladera castanea Arrow (Coleoptera: Scarabaeidae). MS thesis, UConn. 1-95.
Hallock, H.C. 1936. Life history and control of the Asiatic garden beetle. USDA Circ. 246: 1-20.
Hammond, R. 2013. Asiatic garden beetle could be cause for concern for northern Ohio corn. About Us: News. OSU, Department of Entomology. Accessed on March 20, 2017. https://cfaes.osu.edu/news/articles/asiatic-garden-beetle-could-be-cause-for-concern-for-northern-ohio-corn
Kanzaki N., K. Futai. 2002. A PCR primer set for determination of phylogenetic relationships of Bursaphelenchus species within the xylophilus group. Nematology. 4(1): 35-41.
Kaya, H.K., T.M. Burlando, G.S. Thurston. 1993. Two EPN Species with Different Search Strategies for Insect Suppression. Environ. Entomol. 22(4): 859-864.
Kergunteuil, A., M. Bakhtiari, L. Formenti, Z. Xiao, E. Defossez, S. Rasmann. 2016. Biological control beneath the feet: A review of crop protection against insect root herbivores. Insects. 7(4): DOI:10.3390/insects7040070
Krupke, C., J. Obermeyer, L. Bledsoe. 2007. A new field crops pest for Indiana: Asiatic garden beetle. Purdue Cooperative Extension Service. Accessed March 20, 2017. https://extension.entm.purdue.edu/pestcrop/2007/issue11/
Lacey, L.A., R. Georgis. 2012. EPN for control of insect pests above and below ground with comments on commercial production. J. Nematol. 44(2): 218-225.
Morales-Rodriguez, A., A. Ospina, D.C. Peck. 2010. Variation in the laboratory susceptibility of turf infesting white grubs (Coleoptera: Scarabaeidae) to biological, biorational and chemical control products. Pest Manage. Sci., 66: 90-99.
Powers, T.O., E.C. Bernard, T. Harris, R. Higgins, M. Olson, M. Lodema, P. Mullin, L. Sutton, K.S. Powers. 2014. COI haplotype groups in Mesocriconema (Nematoda: Criconematidae) and their morphospecies associations. Zootaxa. 3827(2): 101-146. http://dx.doi.org/10.11646/zootaxa.3827.2.1.
Rasmann, S., T.G. Kollnwe, J. Degenhardt, I. Hiltpold, S. Toepfer, U. Kuhlmann, J. Gershenzon, T.C.J. Turlings. 2005. Recruitment of entompathogenic nematodes by insect-damaged maize roots. Nature. 434: 732-737.
Richer, E.A., A. Michel. 2014. Product efficacy on Asiatic garden beetles in field corn. OSU Extension. Accessed March 20, 2017. https://agcrops.osu.edu/sites/agcrops/files/ofr_reports/2014%2520Fulton%2520AGBproducts.pdf
Shields, E.J., A. Testa, G. Neumann, K.L. Flanders, P.C. Schroeder. 2009. Biological control of Alfalfa snout beetle with a multi-species application of locally adapted persistent EPN: The first success. Amer. Entomol. 55(4): 250-257.
Tashiro, H. 1987. Turfgrass insects of the United States and Canada. Cornell University Press, Ithaca, NY. 156-192.
Testa, A.M., E.J. Shields. 2017. Low labor “in vivo” mass rearing method for EPN. Biol. Contr. 106: 77-82.
Tiwari, S., C.A. Laub, R.R. Youngman. 2008. Asiatic garden beetle in field corn. Virginia Cooperative Extension. Accessed March 20, 2017. https://pubs.ext.vt.edu/444/444-108/444-108_pdf.pdf
The learning outcomes stemming from this project are that farmers will be able to:
1) understand how EPN provide a sustainable, low input, and
economical management tool with minimal off-target effects
2) learn which EPN AGB is susceptible to
3) identify nematodes based on cadaver color and texture
4) learn how to rear and applying EPN at home for personal use
The action outcomes from this study are that farmers interested in utilizing EPN for management of AGB in corn will be able to:
1) rear their own EPN for application on their personal farms
2) use local EPN for management of AGB in corn
3) minimize insecticide use for management of AGB in corn.