Gouty Pitch Midge
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Hagle, S.K; S. Tunnock; K.E. Gibson; and C.J. Gilligan. 1987. Field Guide to Diseases and Insect Pests of Idaho and Montana Forests. U.S. Department of Agriculture, Forest Service. State and Private Forestry, Northern Region. Missoula, Montana. Reprint 1990. Publication Number R1-89-54.
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Contents |
Hosts
Ponderosa pine; occasionally lodgepole pine.
Distribution
Throughout host range.
Damage
Attacks occur near branch tips in early summer. New shoots fade, droop, turn yellow, and die. Repeated attacks which do not kill the shoots may twist and stunt branches. Beneath the bark, small resinous pockets are formed by developing larvae. Trees 4-16 feet in height are most heavily infested. Small trees may be killed.
Identification
Needles on infested shoots die in tufts which soon droop and turn yellow. Later they become red-brown (fig. 86). These flags are scattered over part or all of the crown and appear by summer. Extensive twig killing, stunted or distorted growth, and sparse, off-colored foliage are symptoms of persistent heavy infestations. Infested shoots will have slight swellings on their surface which enclose bright orange to red maggots about one-eighth of an inch long (fig. 87) from July to the following June. The resin infiltrates the wood around pits and sometimes exudes over the twig. Larvae overwinter in pits under bark. Adults emerge in early spring after larvae migrate to surface of branch to pupate.
Similar damages
Damage is similar to Diplodia blight. Pitchy "gouts' on twigs and larvae, when present, distinguish this pest.
References
- Anonymous. 1982. For. Insect & disease identification and management. USDA For. Serv., Northern Region; Idaho Dept. of Lands, Insect and Disease Control; Montana Dept. of State Lands, Division of Forestry. 192 p.
- Eton, C.B., and J.S. Yuill. 1971. Gouty pitch midge. USDA For. Serv., For. Pest Leaflet 46, 8 p., illus.
- Furniss, R.L., and V.M. Carolin. 1977. Western For. Insects. USDA Forest Serv., Misc. pub. 1339, 654 p., illus.
