Areawide management of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), using selected cover crop plants

Authors: Meagher, Robert - Rob; Nagoshi, Rodney; FLEISCHER, SHELBY - Pennsylvania State University; Westbrook, John; WRIGHT, DAVID - University Of Florida; Morris, John - Brad; Brown, James; Rowley, Amy

Submitted to: CABI Agriculture and Bioscience (CABI A&B)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2021
Publication Date: 1/3/2022
Citation: Meagher Jr, R.L., Nagoshi, R.N., Fleischer, S.J., Westbrook, J.K., Wright, D.L., Morris, J.B., Brown, J.T., Rowley, A.L. 2022. Areawide management of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), using selected cover crop plants. CABI Agriculture and Bioscience (CABI A&B). 3:1. https://doi.org/10.1186/s43170-021-00069-0.
DOI: https://doi.org/10.1186/s43170-021-00069-0

Interpretive Summary: The fall armyworm moth (FAW) is a serious pest of row and vegetable crops in the U.S. FAW originated in the tropics and cannot withstand freezing temperatures during winter. However, every growing season FAW infest crops as far north as southern Canada by migrating each spring from southern Florida and southern Texas northward. Researchers from USDA-ARS Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida, Pennsylvania State University, State College, PA, USDA-ARS, SPARC, College Station, TX and USDA-ARS, PGRCU, Griffin, GA, collaborated to conduct field and laboratory experiments to compare the use of cover crop plants in delaying migration. The field studies examined plots planted with two alternative plants, sunn hemp and cowpea, as well as with the standard cover crop plant, sorghum-sudangrass. Sunn hemp and cowpea plants had caterpillar populations that were 70-96% less than sorghum-sudangrass plants. In addition, a laboratory study compared larval feeding on different sunn hemp germplasm lines and the results indicated there were no differences. These studies show that sunn hemp has the potential to reduce migrating populations of fall armyworm when planted as a cover crop.

Technical Abstract: A series of field experiments and a laboratory feeding study were conducted to compare infestation and feeding and of fall armyworm, Spodoptera frugiperda (J. E. Smith), on different cover crop plants. Field experiments had plots planted with corn (Zea mays L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench], a standard cover crop in Florida, and two alternative cover crops, sunn hemp (Crotalaria juncea L.) and cowpea [Vigna unguiculata (L.) Walpers spp. unguiculata]. Field populations of fall armyworm were highest on corn, followed by sorghum-sudangrass. Sunn hemp and cowpea had larval populations 70-96% less than on sorghum-sudangrass, suggesting replacement of this cover crop with either plant species might help reduce areawide populations of resident or migratory fall armyworm. Larvae collected from cover crop plots had parasitism levels that averaged 30%, with Chelonus insularis (Hymenoptera: Braconidae) emerging as the most commonly-collected species. Larval feeding on different sunn hemp germplasm lines resulted in no difference among lines in weight gain; therefore, all lines tested should be acceptable as a replacement cover crop for areawide management of fall armyworm.