You might think a farmer's worries are over when it rains. Not so in East Texas. Some East Texas pastures that have seen rain in the past few weeks have been besieged by armyworms, says James Robinson, Texas Agricultural Extension Service entomologist based at Overton. Armyworms consume tremendous amounts of grass in their last three days before pupating. The larva form of a migrating moth, the armyworm is named for its habit of moving across pastures in large numbers like the legions of an advancing army, devouring grasses in their wake.
Armyworm moths migrate in the millions northward from South Texas in the spring and summer.
As part of their natural life cycle, each moth will deposit a clump of 50 or more eggs on individual blades of grass. During a drought, most of the eggs dry up or die within a few days. If the armyworms do hatch, they find nothing to eat and die. The moths are persistent, however, and continue to migrate and lay eggs throughout the summer, drought or no drought. When their egg- laying coincides with a rainfall, the armyworms successfully hatch in droves and immediately start maneuvers.