Determination of cresidual control and concentration of chlorantraniliprole in soybean

Authors: SMITH, JACOB - Mississippi State University; CROW, WHITNEY - Mississippi State University; CATCHOT, ANGUS - Mississippi State University; COOK, DON - Mississippi State University; GORE, JEFF - Mississippi State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2023
Publication Date: 2/8/2023
Citation: Smith, J., Crow, W., Catchot, A., Cook, D., Gore, J. 2023. Determination of cresidual control and concentration of chlorantraniliprole in soybean. Journal of Economic Entomology. 116(42):472-477. https://doi.org/10.1093/jee/toad021.
DOI: https://doi.org/10.1093/jee/toad021

Interpretive Summary: Studies were conducted in 2020 and 2021 at the Delta Research and Extension Center in Stoneville, MS to determine concentrations of a insecticide used for caterpillar control (chlorantraniliprole) in soybean leaves and florets. Chlorantraniliprole was applied as a foliar spray at four rates for leaves and two rates for florets. Tests with treated plant tissues with corn earworm caterpillars were conducted concurrently to determine mortality within three plant zones to evaluate chlorantraniliprole distribution throughout the plant canopy. For the leaf study, plants were partitioned into three zones consisting of a top, middle, and bottom zone. Leaf samples from each zone were analyzed for chemical concentrations and bioassays were conducted at 1, 7,14, 21, and 28 days after treatment. Floret samples were analyzed at 4, 7, 10, and 14 days after treatment. Concentrations of chlorantraniliprole, though variable, provided >71% control through all sampling dates, application rates, and canopy zones tested. Chlorantraniliprole was viable up to 4 weeks after treatment. Results from the soybean floret study suggested chlorantraniliprole was detected in florets up to 2 weeks after treatment. An additional leaf test was conducted using concentrations detected in the floret study. Concentrations in florets provided mortality of corn earworm up to 48% out to 2 weeks after treatme. With a long residual expected, chlorantraniliprole applications should continue to be used to control corn earworm infestations in soybean and some additional control could be expected in florets.

Technical Abstract: Studies were conducted in 2020 and 2021 at the Delta Research and Extension Center in Stoneville, MS to determine concentrations of chlorantraniliprole (Prevathon, FMC Corporation, Philadelphia, PA) in soybean (Glycine max L.) leaves and florets. Chlorantraniliprole was applied as a foliar spray at four rates (0.028, 0.053, 0.078, 0.103 kg ai ha-1) for leaves and two rates (0.053, 0.078 kg ai ha-1) for florets. Leaf bioassays with corn earworm, Helicoverpa zea (Boddie), were conducted concurrently to determine mortality within three plant zones to evaluate chlorantraniliprole distribution throughout the canopy. For the leaf study, plants were partitioned into three zones consisting of a top (18th node), middle (13th node), and bottom (9th node) zone. Leaf samples from each zone were analyzed for chemical concentrations and bioassays were conducted at 1, 7,14, 21, and 28 days after treatment (DAT). Floret samples were analyzed at 4, 7, 10, and 14 DAT. Concentrations of chlorantraniliprole, though variable, provided >71% control through all sampling dates, application rates, and canopy zones tested. Chlorantraniliprole was viable up to 28 DAT. Results from the soybean floret study suggested chlorantraniliprole was detected in florets up to 14 DAT. An additional leaf bioassay was conducted using concentrations detected in the floret study. Concentrations in florets provided mortality of corn earworm up to 48% out to 14 DAT. With a long residual expected, chlorantraniliprole applications should continue to be used to control corn earworm infestations in soybean and some additional control could be expected in florets.