We are seeing armyworms in grasses and soybeans, budworm/bollworm in cotton, and cutworms in sesame. Yes I said sesame. we are even being overrun in the landscape and garden. Most of these larvae (caterpillars) are immature moths. The moths fly to a suitable host and lay eggs. These eggs hatch in about 3 days and the small caterpillars begin to feed. Feeding lasts about 2 weeks. After the caterpillar has done the damage they usually pupate for about 10 days. After this time the adult emerges and starts the cycle over again.
Here are some images to help you identify your pest. You can also visit http://www.bugwood.org/ to view all sorts of insect images from across our area.