Columbia subject headings:
Harvard subject headings:
Shrubs--Diseases and pests--Canada--Pictorial works.
Shrubs--Diseases and pests--Canada.
Shrubs--Diseases and pests--United States--Pictorial works.
Shrubs--Diseases and pests--United States.
Trees--Diseases and pests--Canada--Pictorial works.
Trees--Diseases and pests--Canada.
Trees--Diseases and pests--United States--Pictorial works.
Trees--Diseases and pests--United States.
Princeton subject headings:
Shrubs--Diseases and pests--Canada--Pictorial works.
Shrubs--Diseases and pests--Canada.
Shrubs--Diseases and pests--United States--Pictorial works.
Shrubs--Diseases and pests--United States.
Trees--Diseases and pests--Canada--Pictorial works.
Trees--Diseases and pests--Canada.
Trees--Diseases and pests--United States--Pictorial works.
Trees--Diseases and pests--United States.