Subject
Control
Spruce budworm
66
Diseases and pests
32
Forest insects
31
Pests
18
Aerial spraying and dusting in forestry
16
Forests and forestry
15
Pesticides
14
Trees
14
Environmental aspects
13
Insect pests
12
Insecticides
12
Bacillus thuringiensis
9
Spruce
9
Weeds
9
Gypsy moth
8
Application
7
Forest management
7
Congresses
6
Forest protection
6
Herbicides
6
Biological control
5
Behavior
4
Brush
4
Coyote
4
Coyotes
4
Ecology
4
Pest management
4
Research
4
Toxicology
4
Weed control
4
Balsam fir
3
Christmas tree growing
3
Environment
3
Forest nurseries
3
Forestry
3
Management
3
Pest control
3
White pine weevil
3
Biocides
2
Canker-worms
2
Christmas trees
2
Coal
2
Economic aspects
2
Fall cankerworm
2
Hardwoods
2
History
2
Insects
2
Population
2
Populations
2
more ...