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Tent Worms in Soya Beans

Tent worms, also called caterpillars, are the larval stage of certain moth species. They are called tent worms because the silk webs they build on their host plants are similar to tents. Several silk-producing moth species spend the larval stage of life eating holes in the leaves of plants. Most species eat tree leaves, but some infect crop plants including soybeans, sometimes called soya beans.

Life Cycle
- Catapillars morph into moths and butterflies inside cocoons.
  
  Plants play an important role in the life cycle of tent worm-type moths. Most of these species begin life as an egg affixed to the host plant, either singly on leaf tissue or in an egg mass on a stem. When the egg matures, it becomes a wormlike larva called a caterpillar. The caterpillar eats the leaf tissue to sustain itself as it grows. Some species build tentlike silk web nests that the caterpillars retreat to at night, while others web leaves together to protect themselves from predators as they eat. Once the caterpillar matures, it builds a cocoon and pupates until it emerges as a moth.
Saltmarsh Caterpillar
- Saltmarsh caterpillars can infect more than 100 plant species across North America. The adult moths spend winter in the warm south and fly north as far as Canada during the summer. They lay individual eggs on top of the host plants leaves, and these eggs hatch into black and yellow spiny caterpillars. The caterpillars wrap silk webs around leaves as they eat. Host plants include soybeans and sunflowers.
Webworms
- The term "webworm" refers to several web-building moth species including alfalfa webworm, beet webworm and garden webworm. All of theses species will infect soybean crops. To identify a webworm infestation, look for webbed-together tattered leaves and green caterpillars with dark spots. Webworms overwinter in the soil and emerge in the spring to find nearby host plants.
Other Soybean Worms
- Many caterpillars will chew up soybean leaves without building webs. These species include green cloverworm, variegated cutworm, cabbage looper, yellow striped armyworm, soybean looper, corn earworm and velvetbean caterpillar.
Control
- Usually, caterpillars do not do enough damage to soybean crops to make implementing chemical controls economical. But when they do, Bacillus thuringiensis, also called Bt, is commonly used to kill caterpillar pests. A naturally occurring soil bacterium, Bt kills caterpillars by sticking to the caterpillar's gut lining and robbing it of energy. The caterpillars must eat the Bt for it to be effective. Bt does not harm humans or other animals. Some commercial insecticides are also labeled for use in controlling pest caterpillars. For a manual method of control, remove small infestations by handpicking the caterpillars and submerging them in soapy water.

Insects & Science