Tent and larvae of the
western tent caterpillar

Leaf Feeding Caterpillars

Description

The adults are typically nondescript moths. Only the larvae stage is damaging. Because there are many different species of leaf feeding caterpillars they vary in size, shape and coloration. The larvae will have six legs and are typically yellow or green. In the case of tent making caterpillars they are hairy, yellow-brown with rows of blue and orange spots on the body.

Plants Affected

Many species of fruit, native and ornamental trees are affected including; apple, pear, cherry, plum, walnut, rose, privet, oak, alder, willow, dogwood.

Symptoms/Damage

The larvae will spin a light web and roll the leaf leaving a distorted and unsightly appearance to the plant. If the insect population is high, part or the entire canopy can be defoliated causing great stress to the plant. Tent making caterpillars will spin large webs or tents and feed on leaves inside.

Life Cycle

Leaf rollers will overwinter as immature larvae protected by a cocoon or as eggs, depending on the species. Cocoons and eggs can be found in bark crevices or beneath bud scales. In spring, the larvae emerge from either their cocoon or egg, migrate to leaves or fruit and begin to feed. Once mature, the larvae select a leaf and construct a shelter by rolling it up using a silken material. Within this structure, the larvae will feed for a number of weeks then pupate and eventually emerge as adults. The adults mate and lay eggs that will overwinter until next spring or the eggs will hatch creating a second generation. The second generation only reaches the larval stage by winter. These larvae overwinter in cocoons.

We have two species of tent making caterpillars; the western tent caterpillar larvae hatch in the spring and the fall webworm emerges to feed in the summer months.

Management

Cultural

 Tents may be cut out and destroyed.

Biological

 Parasitic wasps and flies
 Bacillus thuringeinsis – provides good control with multiple applications

Organic

 Pyrethrins and neem oil can provide good control.

Chemical

 Approved insecticides can be used when populations are high. The best time for control is in the early spring during leaf expansion.