Western Gall Rust
From Bugwoodwiki
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.
Contents |
Hosts
Lodgepole and ponderosa pines.
Distribution
Range of hosts in Idaho and Montana.
Damage
Galls form on infected branches or stems (fig. 20). Branches and small stems are killed when insects and other fungi attack galled tissue. Cankers are produced from stem galls as trees grow.
Identification
Round swellings (galls) form on branches or stems. Pustules of yellow or orange spores form in bark cracks on galls in spring. In very young trees such as 2-year-old nursery stock, slight spindle-shaped swellings are seen on the lower stern. In saplings and larger trees stem infections eventually form flared, target cankers (cankers with concentric ridges of sapwood) called "hip cankers" (fig. 21). Sporulation can some times be seen at the edges of hip cankers in spring.
Similar damages
Comandra blister rust stem cankers are sometimes mistaken for gall rust hip cankers. Comandra cankers are usually somewhat longer than they are wide.
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.
- Bega, R. V. 1978. Diseases of Pacific Coast conifers. USDA For. Serv. Ag. Hndbk. No. 521, 206 p.
- Boyce, J. S. 1961. Forest Pathology. McGraw-Hill Book Co., New York, NY. 572 p.
- Hepting, G. E. 1971. Diseases of forest and shade trees of the United States. USDA For. Serv. Ag. Hndbk. No. 386, 658 p.
- Peterson, R. W. 1960. Western gall rust on hard pines. USDA For. Serv., For. Ins. & Dis. Leaflet 50, 8 p.
- Ziller, W. G. 1974. The tree rusts of western Canada. Can. For. Serv., Publ. No.1329, Dept. of the Env., Victoria, B.C. 272 p.
