Forest Health Protection and State Forestry Organizations January 2006

10.2 Management Guide for WEB July 2010 Coneworm Management

By Sandy Kegley Diorvctria abietivorella (Grote) US Forest Service

This moth is a chronic Hosts: pest in western white  Douglas-fir  Spruces pine seed orchards in  True firs  Western hemlock northern Idaho and  Mountain hemlock Douglas-fir stands in  All pines

Montana.

Topics Damage

Damage 1 Larvae mine and riddle western white pine, and ponderosa cones—feeding on cone tissue and pine and have been found infesting Life History 1 seeds. They are very mobile and western white pine blister rust Identification 2 will emerge from feeding on one canker margins. Frass and webbing Management 2 cone to continue feeding on are obvious on the outside of cones another. Larvae can also bore into and bark where coneworms have Other Reading 2 graft unions of Douglas-fir, been feeding. Field Guide

Management Life History Guide Index Life history is variable and not well known. Larvae develop from June through September in Key Points the new growing cones. Some  Detection seen larvae pupate in cocoons on the as conspicuous ground during July, August and clumps of frass September and adults emerge stuck together shortly after to lay eggs, which with silk webbing overwinter. Other larvae on the outside of overwinter as prepupae in cocoons Coneworm frass on outside of larch cones. in the ground, or in cones, pupate cone. Photo from FHP photo library. in the spring and emerge as adults  Insecticides have during May and June. Eggs are proven effective laid on twigs and cone bracts. Identification in managing coneworm Coneworm presence in cones or populations in in graft unions can be detected by western white conspicuous clumps of frass stuck pine seed together with silk webbing on the orchards. outside of cones or bark. Damaged cones may also have circular exit holes and can be discolored. Mature

Photo above: Coneworm adult moth. larvae are about 18 mm long with a Photo from FHP photo library. deep amber brown, shiny head. Page 2 Back to menu Coneworm 10.2

The body is amber brown to *Chemical insecticide reddish-purple with faint dorsal registrations for lines and broader subdorsal stripes. control change Adults are gray and white with dark frequently. Contact County, State, or gray crossbands on the forewings. Federal pesticide Hind wings are pale gray. coordinators for updates Wingspan is about 25 mm. on current insecticide registrations and application methods.

Management Chemical contols Insecticides have proven effective in managing coneworm Infested and normal populations in western white pine seed orchards. Two western white pine cone. Note discoloration and applications of fenvalerate*, a synthetic pyrethroid, applied frass on infested cone. in May and again in June, significantly increased seed yield Photo by Sandra Kegley (Haverty et al. 1986).

Monitoring Pheromones have been identified but appear to be unstable in the field. Recently, research identified a new pheromone formulation which has shown promise and may be available for use in the near future. Pheromones can be used in traps to monitor populations and determine timing for insecticide treatments. They might also be used in mating disruption and trap out strategies in seed orchards. Coneworm larva inside western white pine cone. Photo by Sandra Kegley

Other Reading Forest Health Protection and State Forestry Organizations Haverty, M.I.; Shea, P.J.; and Stipe, L.E. 1986. Single and multiple applications of fenvalerate to protect western white pine Assistance on State Assistance on cones from abietivorella (Lepidopters: And Private Lands Federal Lands ). Journal of Economic Entomol. 79(1): 158-161. Montana: (406) 542-4300 US Forest Service Region Hedlin, A.F.; Yates, H.O. III; Cibrian-Tovar, D.; Ebel, B.H.; One Idaho: (208) 769-1525 Koerber, T.W.; Merkel, E.P. 1981. Cone and seed Missoula: (406) 329-3605 Coeur d’Alene: (208) 765 of North American conifers. Canadian Forestry Service, Utah: (801) 538-5211 -7342 United States Forest Service, Secretaria de Agricultura y

Nevada: (775) 684-2513 Recursos Hidraulicos, Mexico. 122 p. US Forest Service Region

Wyoming: (307) 777- Four Koerber, T. W., et al. 1976. Preventing fir coneworm damage to 5659 Ogden: (801) 476-9720 newly grafted ponderosa pine. Tree Planters' Notes 27(2): Boise: (208) 373-4227 18-19. N.Dakota (701) 228-5422

Sopow, S.L.; Benett, R.G.; Landry, J.F.; Landry B. 1996. Identification of the “grey” Dioryctria species of British Columbia (, Pyralidae). J. Entomol. Soc. Brit. Columbia 93: 75-92. Disclaimers | Privacy Policy