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

Abstract

Background Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a migratory moth that annually migrates northward each spring from sites in southern Florida and southern Texas. This caterpillar pest feeds on and damages row, turf and vegetable crops in the eastern and central U.S. Before migrating in spring, it feeds on cover crops in central and eastern Florida and expands its populations. Our objective was to use multi-year studies to compare fall armyworm populations that develop in cover crop plants. Methods A series of field experiments and a laboratory feeding study were conducted to compare infestation and feeding and of fall armyworm 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]. Another trial compared populations in sorghum-sudangrass and in mixtures of sorghum-sudangrass with buckwheat (Fagopyrum esculentum Moench) or pearl millet (Cenchrus americanus (L.) Morrone). Fall armyworm larvae were fed and allowed to develop on different sunn hemp germplasm in a laboratory trial. Results 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 in weight gain. Conclusions Replacing sorghum-sudangrass with sunn hemp varieties or germplasm should be acceptable as a replacement cover crop for areawide management of fall armyworm.

Comparison of Carabid Densities in Different Cover Crop Species in North Florida

“…Cover crops were planted at the University of Florida (UF) North Florida Research and Education Center, Quincy, Florida in 2011 and 2012 (Gadsden county; 30.5460000 °N, 84.5990000 °W), and at the UF/IFAS (Institute of Food and Agricultural Sciences) Plant Science Research and Education Unit, Citra, Florida in 2012 and 2013 (Marion county; 29.4100000 °N, 82.1730000 °W). These plots were the same ones used for the fall armyworm infestation trials (Meagher et al 2022). Briefly, the experimental design at both locations was a randomized complete block with 4 cover crop treatments, 4 blocks, and 6–12 row plots that were 15.24–30.50 m long and were planted on 91.4 cm row centers.…”

“…Cowpea is a warm-season annual legume that alone or mixed with sorghum-sudangrass can be used as a cover crop or intercrop with vegetables (Cho et al 2012; Harrison et al 2014). More comprehensive studies after Meagher et al (2004) showed sunn hemp and cowpea had fall armyworm populations 70–96% less than sorghum-sudangrass (Meagher et al 2022), concluding that substituting sorghum-sudangrass with these plants could be preferable as a replacement cover crops for areawide management of fall armyworm.…”

“…; Fabaceae) and rapeseed (Brassicae campestris L. variety chinensis; Brassicaceae) and can develop large populations that then infest surrounding vegetable and row crops (Tuan et al 2014). Fall armyworm develops well on certain grass cover crops such as corn and sorghumsudangrass, thereby increasing their populations to either infest adjoining crops or migrate northward (Pair & Westbrook 1995;Meagher et al 2004Meagher et al , 2022.…”

Cascading Effects of Cover Crops on the Subsequent Cash Crop Defense against the Polyphagous Herbivore Fall Armyworm (Spodoptera frugiperda)

“…In recent years, it has emerged as one of the most important global polyphagous pests of crops [ 20 , 21 ]. FAW is a serious concern in various agroecosystems and can feed on most of the cover and cash crops [ 22 , 23 ]. The management of FAW in recent years has ranged from the use of synthetic pesticides to biopesticides, cultural control, and biological control [ 20 ].…”

Managing fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae): Experience from smallholder farmers in central and western Africa

“…Since its invasion in all tropical and subtropical regions of the world, the FAW has attracted increasing research interest to find sustainable management options through agroecological practices and the use of biopesticides (Bateman et al, 2018; Harrison et al, 2019; Midega et al, 2018). In the Americas, producers and researchers have long studied FAW and their experiences are being used to develop sustainable management options appropriate for large‐scale farmer systems (Meagher et al, 2022; Sparks, 1986). For example, in the United States, Brazil and Argentina, FAW was commonly controlled by the application of effective pesticides and the use of genetically modified corn (Bt corn), which incorporated genes to produce lethal toxins against FAW (Hruska, 2019).…”