Forest Health Protection and State Forestry Organizations January 2006

6.8 Management Guide for WEB Feb 2010 Pandora By Steve Munson pandora (Blake) US Forest Service

One of the largest defoliating Hosts: Occasional in North America. Found  Ponderosa hosts: in the Western United States  Jeffrey pine  Sugar mainly in Utah, Wyoming,  Lodgepole pine  Coulter Colorado, Montana, Nevada,  pinyon , and Oregon.

Topics Damage 1 Damage Life History 1 Defoliation occurs only every terminal buds are not damaged thus Identification 2 other year because of the insects 2- new needles are formed. Management 2 year lifecycle. Epidemics occur at intervals of 20 to 30 years and may Other Reading 3 last from 6-8 years. Field Guide Larvae feed on older foliage, leaving the tree with a tufted Figure 1. Management appearance (Figure 1). Infested Defoliation Guide Index damage from the trees have a reddish top with foliage Pandora moth only at branch tips. Tree mortality larvae within a pine stand.. Photo can occur as the result of heavy by Donald Owen. repeated defoliation. Reduced redial growth and loss of tree vigor occurs during each defoliation event. Key Points During the spring, needle growth of  Defoliation all sizes are consumed. However, occurs only every other year because of Life History the insects 2- Pandora have a 2-year average of 80 eggs distributed in year lifecycle. lifecycle, spending the first winter as several clusters, usually on the bark  Larvae feed on larvae in the tree canopy and the and needles of pines. Eggs are older foliage, second as pupae in the litter or soil. occasionally deposited on the leaving the tree Caterpillars prefer to pupate in ground litter or brush. Eggs hatch with a tufted pumice or decomposed granite soils. in August approximately 40-50 days appearance The adult moths emerge from pupal after egg deposition. Young larvae cases in June or July. Pupation feed in clusters on needles of the  Tree mortality typically lasts for about a year, but terminal shoots and overwinter at can occur as occasionally extends up to four the base of the needles. Larvae the result of years. Defoliation and adult moth overwinter primarily in the second heavy repeated flight occur in alternate years. instar and may begin feeding as defoliation. Females generally do not fly until early as April in warmer climates. after mating. Females lay an Page 2 Back to menu Pandora Moth 6.8

Identification

Full grown caterpillars are large infested overstory trees due to the (2 ½-3” long) with a few stout, enormous quantity of needles branched spines appearing on each consumed by caterpillars. Pupae segment. Mature caterpillars are are stout, dark reddish or purplish- gray with a white stripe down their brown, 1 to 1 ½ inches long and back with orange-brown heads found in the soil. (Figure 2). Adult moths are gray, thick bodied with a wingspan of Figure 2. of Pandora moth feeding on pine three to five inches. Forewings are needles. Photo from Forest brownish gray, hind wings are Service - Region 4 Archives. pinkish gray, with a black dot and wavy line on each wing (Figure 3). Female moths have narrow antennae whereas the males are feathery. Moth flights to nearby sources of light are sometimes the first indication of an increasing population of Pandora moth. Figure 3. Female Pandora moth with Masses of greenish or brownish distinctive narrow antennae. Photo from droppings can be found under Forest Service - Region 4 Archives.

Some Native American tribes have Management collected and used Pandora Natural Control- There are some natural control factors moth larvae such as overwintering mortality, predators, parasites, high and pupae as soil temperatures as larvae enter the soil for pupation and a food, which polyhedrosis virus (wilt disease) affecting mature larvae. may have Rodents, ground squirrels and chipmunks are major affected local predators of pupae. A few species of birds are predators of populations of eggs (nuthatches and creepers) and larvae (Steller jays and the . vireos). Some birds are repelled by the spines on the larvae.

Chemical Control- Insecticide treatments are generally not required since natural control agents suppress outbreaks before extensive tree mortality occurs. Broad spectrum insecticides may be available in some states to suppress populations. Bacillus thuriengensis may be an effective insecticide treatment if applied to early instar larvae. Prescribed burning treatments have been used to kill pupae and larvae with variable success. Page 3 Back to menu Pandora Moth 6.8

Other Reading Carolin, V.M. and A.E. Knopf. 1968, The Pandora moth. U.S. Department of Agriculture, Forest Service, Forest Pest Leaflet 114, 7 p.

Cranshaw, W.S., D. Leatherman, B. Kondratieff. 1994. Insects that feed on Colorado trees and shrubs. Colorado State University, Ft. Collins, CO. Bulletin 506A. 176 p.

Furniss, R.L. and V.M. Carolin. Western Forest Insects. U.S. Department of Agriculture, Forest Service, Misc Pub. No. 1339. 654 p.

Forest Health Protection and State Forestry Organizations

Assistance on State Assistance on And Private Lands Federal Lands

Montana: (406) 542-4300 US Forest Service Region One Missoula: (406) 329-3605 Idaho: (208) 769-1525 Coeur d’Alene: (208) 765-7342

Utah: (801) 538-5211 US Forest Service Region Four

Ogden: (801) 476-9720 Nevada: (775) 684-2513 Boise: (208) 373-4227

Wyoming: (307) 777-5659

N.Dakota: (701) 228-5422

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