Archips cerasivorana

Larva

The larvae are distinct by their coloration. Early instars are yellowish-green with black legs, head, prothoracic shield, and anal shield. The later instars are bright orange with the same contrasting dark sclerotization and with sparse moderately long pale setae.[7] Last instar larvae are 19–26 mm in length with a yellow to dark yellowish-green abdomen. The head, prothoracic shield, thoracic legs, and anal shield are dark brown to black. An anal comb is absent.[6] Larvae of Archips rileyana are very similar to those of A. cerasivorana.

In adult males, the forewing length ranges from 7.5-9.5 mm; and 9.0-12.0 mm in females.[6] The adults are easily recognized by the orange forewing with many silvery bars. Forewing color varies from bright orange to yellow, often with faint purplish markings. Males have a forewing costal fold. There are distinct brown squared blotches along the costa in the postmedian and median area, along with variable smaller brown markings through the middle of the wing in the antemedian and median areas. The hindwings and most of the body is also orange. The wingspan is 20–25 mm. The hindwings are yellow with orange shading.

Tent

From the first instar, the caterpillars will aggregate and build large tent structures. These caterpillars are one of the few in the family Tortricidae that exhibit social behavior.

They make these tents by spinning silk threads between leaves and branches, which draws them into a compact nest. Each strand of silk is stretched slightly before it is attached to a leaf so that a tiny force (from axial retraction) will pull the leaf slightly towards the nest. When many strands of silk are spun to the surrounding leaves, the net forces will eventually drive all the leaves into the characteristic tent shape.[10][11] The caterpillars usually stay within boundaries defined by the silk that envelops their shelter. They occasionally venture out of the nest, traveling only short distances to draw in new leaves. In most cases, the colony finds a sufficient number of leaves in its contiguous patch to complete larval development.

If all of the leaves within a tent are consumed before the caterpillars are ready to pupate, the caterpillars will be forced to leave their nest and find a new nesting location. During these migrations, the caterpillars will depart individually or in small groups, leaving small silken trails laced with pheromones to guide the next caterpillar.[2]

Trail-following has been hypothesized as a product of both chemical and physical input.[2]

Research has shown that trail-following behavior in a caterpillar originates, in part, from the following of pheromones left by other caterpillars. Each caterpillar secrets marker pheromones secreted from glands by the spinnerets, no other regions of the body have been shown to secrete pheromones. Experiments have shown that caterpillars are capable of following trails prepared with gland extracts, but such trails were markedly less effective than originally-intact control trails. Also, caterpillars display a preference for silk-like trails. When presented with a variety of pheromone-trail mediums, from nonporous steel, to cotton, to the original trail, experimental caterpillars preferred the original silk trail.[2]

The best means for removal is to prune and destroy webbed nests.[12]

The caterpillars can also be chemically removed through use of pesticides. Pesticides like the bacteria Bacillus thuringiensis can be sprayed to control young larvae. Larger populations of older larvae can be controlled with a residual insecticide, but damage is rarely sufficient to warrant treatment that may endanger the rest of the local environment. Biorational pesticides like insecticidal soap, pyrethins, spinosad, and tebufenozide can also be used.[14]