Woolly apple aphid damage. Photo by: Whitney Cranshaw, Colorado State University, Bugwood.org.

Wooly apple aphid infestation. Photo by: Joseph Berger, Bugwood.org.

Woolly apple aphids. Photo by: Whitney Cranshaw, Colorado State University, Bugwood.org.

Larch casebearer damage. Photo by: erald E. Dewey, USDA Forest Service, Bugwood.org.

Larch casebearer larva. Photo by: Ian Kimber, Bugwood.org.

Larch casebearer adult. Photo by: Ian Kimber, Bugwood.org.

Hemlock woolly adelgid. Photo by: James Johnson, Georgia Forestry Commission, Bugwood.org.

Fusiform rust on loblolly pine. Photo by Nancy Gregory, Plant Diagnostician, University of Delaware.