Growers are noting significant damage from fall armyworm on rye cover crops used before ginseng planting and rye nurse crops used to anchor the straw after planting. Wheat is also likely to be affected. There has been a major outbreak of fall armyworm on multiple crops over the past few days. For more information and photos of this pest, see this article in Field Crop News:
As noted in the article if the larvae are 2.5 cm (1 in.) long or longer, then it is too late to get good control with insecticides. This is usually the stage at which growers take note of the damage. Insects will feed for another week or two and will be done for the year. If it is too late to control them, waiting two weeks and then re-seeding is the best option. This will ensure the insects are done feeding before the new plants emerge.
If larvae are still smaller than 2.5 cm (1 in.) long, the best insecticide available is Coragen, since it is registered for fall armyworm control on both rye and ginseng. Keep in mind the damage already caused and the cost of the insecticide vs re-seeding. It may be more economical to re-seed that to control the damage. Consult the Coragen label for optimal rates used for fall armyworm and application precautions.