Dichomeris marginella

The juniper webworm is a non-native insect that originates from Europe, first reported in the US in 1910. One generation occurs per year, with adult moths active in June and July in the northern parts of its introduced range (points south may have moth activity in May and June). Moths have a life span of approximately 15 days. Adult female moths are capable of producing 50-130 eggs (some sources say as many as 200). Moths have coppery brown forewings outlined with a band of white on the front and rear margins of the forewings, with approximately 0.6 inch wingspans. This helps identify them, along with their correlation with Juniperus hosts. Females lay their eggs (which are white when first laid, but then turn yellow, orange, and finally red as they develop) singly on leaves or near current year's shoots. Eggs are broad and rounded, sculptured, and approximately 5 mm. long. The newly hatched larvae begin life as leaf miners, mining many leaves before beginning to feed on leaf surfaces. Once they leave the leaf mining phase, they begin to construct tubes made of silk around their feeding sites. Early infestations are easily missed due to the behavior of young larvae to inhabit the inner foliage of its hosts first. By the fall, nests including multiple larvae (3-5) may be found webbed together. The juniper webworm overwinters as a caterpillar, in the 5th, 6th, or 7th instar. Feeding begins again the following spring. At that time, the majority of the webbing is produced by the caterpillars. Caterpillars are easily hidden in the naturally dense foliage of their hosts, in addition to being concealed in their webs. Mature caterpillars reach approximately 3/4 inch in length and are tan with brown stripes, a black head, and a dark colored thoracic segment just behind the head. Once mature, larvae pupate and adult moths emerge to begin the cycle again. Pupae are light to dark reddish brown and approximately 1/4 inch in length and pupation occurs in whitish silken cases.