HPIPM:Fall Armyworm FC
Author: Frank B. Peairs[1]
Identification (and life cycle/seasonal history)
Fall armyworm, Spodoptera frugiperda (J.E. Smith), adults are about one inch long, with dark and light gray forewings mottled with light and dark spots. The hind wings are grayish to pinkish-white. Fall armyworm larvae have a white inverted Y-shaped mark on the front of their dark head. They are smooth skinned and vary in color from light tan or green to nearly black, with three yellowish-white hairlines down the back. There is a wider dark stripe and a wavy yellow-red stripe on each side. The larval stage lasts from three to four weeks. Fully developed larvae are about 38 millimeters (1.5 inches) long. Unlike armyworms, fall armyworms feed during the day and night, but are usually most active in the morning or late afternoon.
Plant Response and Damage
Small holes and "window pane" feeding characterize early larval feeding on corn leaves and in the whorl. They may enter the ear and feed on new kernels. Larger larvae may be found deep within the whorl often below a "plug" of yellowish-brown frass. Fall armyworm will feed on corn plants in nearly all stages of development, however later plantings which have not yet silked are preferred.
Management Approaches
Resistant Varieties
Control can be expected with Bt corn hybrids containing the Herculex I event. See Managing Corn Pests with Bt Corn, [2], for details on the use of Bt corn hybrids to control corn pests. See [3] for an excellent summary of currently available traits.
Chemical Control
Product list for Fall Armyworm:
| Pesticide | Product/Acre (Fl oz. or oz. product) | Preharvest Interval, remarks |
|---|---|---|
| FastacR,1 | 3.2 - 3.8 | 30 days grain and stover, 60 days forage. 12 hr REI. Extremely Hazardous to Bees! No more than 11.4 fl oz per season. |
| Bacillus thuringiensis1,2 | See labels | 0 days. 4 hour REI. Use of a spreader-sticker is recommended. |
| Beauveria bassiana1,2 | See labels | 0 days. 4 hr REI. Potentially pathogenic to bees; avoid applying where bees are foraging or around hives. |
| beta-cyfluthrinR,1,2 | See labels. | 21 days. 12 hour REI. See labels. First and second instars, only. Extremely Hazardous to Bees! |
| bifenthrinR,1,2 | See labels | 30 days. 12 hour REI. Use rates below 0.08 lb a.i./acre only if spider mites are NOT a concern. Extremely Hazardous to Bees! |
| bifenthrin + chlorpyrifosR,1,2 | See labels | 30 days. 24 hour REI. Maximum 50.5 fl oz product/season. See labels for additional restrictions for individual active ingredients. Extremely Hazardous to Bees! |
| HeroR,1 | 4.0 - 10.3 | 30 days to harvest grain or fodder. 60 days to forage. 12 hour REI. Do not apply more than 0.4 lb ai/acre/crop. Extremely Hazardous to Bees! |
| carbaryl1,2 | See labels | 48 days grain and stover, 14 days silage. 12 hour REI. Extremely Hazardous to Bees! |
| Prevathon | 14-20 | 14 days grain, 1 day fodder, forage, stover, silage. 4 hour REI. Do not apply more than 0.2 lb ai/acre/crop. |
| chlorpyrifos 4ER,1,2 | 16 - 32 | 21 days. 24 hour REI. Not for use on popcorn. Extremely Hazardous to Bees! |
| chlorpyrifos + gamma cyhalothrinR,1,2 | See labels | 21 days. 14 days to graze. 24 hour REI. Extremely Hazardous to Bees! |
| Cobalt AdvancedR,1 | 16-38 | 21 days. 14 days to graze. 24 hour REI. See labels for additional restrictions for individual active ingredients. Extremely Hazardous to Bees! |
| Grandevo1 | 1-3 lbs | 0 days. 4 hour REI. May be repellent to bees. |
| cyfluthrinR,1,2 | See labels | 21 days. 12 hour REI. First and second instars, only. Extremely Hazardous to Bees! |
| deltamethrinR,1,2 | See labels | 21 days to harvest grain or fodder. 12 days to forage. 12 hour REI. Early instars only. Do not apply more than 0.095 lb ai/acre/crop. Extremely Hazardous to Bees! |
| Belt1 | 2 - 3 | 28 days grain, 1 day forage and silage. 12 hour REI. |
| gamma cyhalothrinR,1,2 | See labels | 21 days. 24 hour REI. Do not apply more than 0.12 lb a.i./acre/season. Extremely Hazardous to Bees! |
| lambda cyhalothrinR,1,2 | See labels | 21 days. 24 hour REI. Do not apply more than 0.12 lb a.i./acre/season. Extremely Hazardous to Bees! |
| BesiegeR | 6 - 9 | 1 day for forage, 7 days for hay. 24 hr REI. Make applications when bees are not actively foraging by applying during early morning or evening hours. See labels for additional restrictions for individual active ingredients. Do not apply more than 31 fl oz product/season. |
| methomylR,1,2 | See labels | 21 days to harvest grain or fodder. 3 days to forage. 48 hour REI. Do not apply more than 2.25 lb ai/acre/crop. Extremely Hazardous to Bees! |
| permethrinR,1,2 | See labels | 30 days grain or fodder. 0 days forage. 12 hour REI. Liquids are Extremely Hazardous to Bees! |
| Radiant SC1 | 3 - 6 | 28 days. 3 days forage or fodder. 4 hour REI. Highly toxic to bees! |
| spinosad1,2 | See labels | 28 days grain, 3 days fodder or forage. |
| ConseroR,1 | 2-3 | PHI 28 days, 1 day graze or fodder; REI 24 hrs. See labels for additional restrictions for individual active ingredients. |
| Coragen | 3.5 - 5.0 | 14 days. 4 hour REI. See labels. |
| Mustang MaxxR,1 | 3.2 - 4.0 | 7 days. 12 hour REI. Extremely Hazardous to Bees! No more than 0.10 lb AI/A/season. |
| StallionR,1 | 9.25 - 11.75 | 30 days grain or stover, 60 days forage. 24 hr REI. Extremely Hazardous to Bees! See labels for additional restrictions for individual active ingredients. No more than 11.75 oz per application, 35.25 oz per season. |
| SteedR,1 | 3.5-4.7 | PHI 30 days grain, 60 days forage; REI 12 hrs. See labels for additional restrictions for individual active ingredients. No more than 18.7 fl oz product/season. |
| Triple CrownR,1 | 4.5 - 10.3 | PHI 30 days grain, 60 days forage; REI 12 hrs. See labels for additional restrictions for individual active ingredients. No more than 30.7 fl oz product/season. |
| RRestricted use pesticide. 1Labeled for chemigation. 2Generic active ingredient, several formulations. | ||
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.
