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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #410978
Research Project: Genetic Improvement and Cropping Systems of Warm-season Grasses for Forage, Feedstocks, Syrup, and Turf

Location: Crop Genetics and Breeding Research

Title: Evaluating the agronomic and economic benefit of including spinosad with and without pyrethroid insecticides bermudagrass stem maggot (Atherigona reversura Villeneuve) treatments

Author
item BURT, JUSTIN - University Of Georgia
item BAXTER, LISA - University Of Georgia
item Anderson, William - Bill
item HANCOCK, GUY - University Of Georgia

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2024
Publication Date: 11/11/2024
Citation: Burt, J.C., Baxter, L.L., Anderson, W.F., Hancock, G.A. 2024. Evaluating the agronomic and economic benefit of including spinosad with and without pyrethroid insecticides bermudagrass stem maggot (Atherigona reversura Villeneuve) treatments. Crop Science. 2024; 70011. https://doi.org/10.1002/cft2.70011.
DOI: https://doi.org/10.1002/cft2.70011

Interpretive Summary: An invasive insect called the bermudagrass stem maggot (BSM; Atherigona reversura Villeneuve) invaded the Southeastern United States 13 years ago. It causes significant damage to forage bermudagrass by killing emerging leaves from the plants and thus reducing yields. The insecticide pyrethroid can control the insect, but another insecticide has been proposed to be used for control (spinosad). The objective of this study was to determine the agronomic and economic implications of one or multiple pyrethroid and/or spinosad applications on ‘Alicia’ and ‘Tifton 85’ bermudagrasses. Pyrethroid treatments resulted in a greater yields that would be used for hay compared to no-sprayed control in both cultivars. Spinosad only treatments did not control the insect and yields were no different than the non-sprayed control. Hay quality in the form of crude protein and total digestible nutrients were not different among the insecticide treatments in either cultivar. Two pyrethroid applications resulted in greater net profit compared to all other insecticide treatments. Ongoing research and breeding efforts are focused on BSM tolerance and reduced pyrethroid usage to prevent resistance to this mode of action.

Technical Abstract: The bermudagrass stem maggot (BSM; Atherigona reversura Villeneuve) is known to have an adverse effect on bermudagrass (Cynodon spp.). Currently, two strategically timed pyrethroid applications are recommended for BSM suppression in each harvest cycle. However, producers are interested in applying spinosad because of its residual effects for other insects or reducing the number of pyrethroid applications to cut input costs. Therefore, the objective of this study was to determine the agronomic and economic implications of one or multiple pyrethroid and/or spinosad applications on ‘Alicia’ and ‘Tifton 85’ bermudagrasses. Generally, pyrethroid treatments resulted in a greater herbage accumulation compared to the negative control in both cultivars (p < 0.01). Regardless of cultivar, spinosad only treatments did not improve upon the herbage accumulation observed in the negative control (p > 0.31). Nutritive parameters of crude protein and total digestible nutrients were not impacted by insecticide treatments in either cultivar (p > 0.08). Finally, two pyrethroid applications resulted in greater net profit compared to other insecticide treatments. These data illustrate that there is not an alternative yet for two pyrethroid applications for BSM suppression. Ongoing research and breeding efforts are focused on BSM tolerance and reduced pyrethroid usage to prevent resistance to this mode of action.