Armyworms feed on food crops, grass and garden plants at night. When the food supply is gone, they move en masse to a new site, hence the name armyworm. Armyworms can destroy an entire plant in
just one evening and there may be as many as three generations in one year. They have a monster appetite for foliage, creating browned-out areas in the wake of their feeding activities.
The trick is to find armyworms when they are small and before they do the most damage. Something like 80 percent of the damage from these caterpillars occurs in the last four to five days of their feeding.
They feed for about two-weeks and it is just that last stage that is credited with most of the damage so finding them when they are smaller makes it easy to control them before they cause damage.
Young armyworms are small and it is hard to see them. The best time to check for them is in the morning or evening. To make searching easier farmers can distribute sweep nets to their cattlemen.