Insects of September
Information provided courtesty of Whitney Cranshaw, Colorado State University Department of Bioagricultural Sciences and Pest Management
- Yellowjackets / hornets - Nest size and
nuisance problems peak. Ground-dwelling yellowjackets and the large, paper wasp nests in
trees and on houses attract attention.
- Large spiders - Cat-face and garden spiders
become fully grown and attract attention.
- Large caterpillars - Several species of large
caterpillars (cecropia, polyphemus and sphinx moths) may be found wandering about
landscapes.
- Peach tree borer - Apply rescue treatments
before soil temperatures cool. This includes PDB moth crystal fumigation at the base of
trees.
- Pearslug - The second generation damages
leaves early in the month.
- Slugs - Injury in the garden increases with
cooler weather.
- Aster yellows - Symptoms increase on many
garden flowers and vegetables until frost.
- Bumble flower beetles - These small beetles
can be seen feeding on flowers and the bacterial ooze from trees.
- Millipedes, spiders, crickets - Often move into homes with cool weather the
end of the month.
- Aphids - Several species (willow, oak and
aspen) typically increase in numbers prior to frost.
- Kermes scale of oak - The crawler stage
emerges in late month and may be vulnerable to sprays although research is incomplete.
- Cooley spruce gall - Winged stages return to
spruce and produce overwintering females that appear as "fuzz" on branches. If
sprays are desired for cosmetic reasons, this is one of two times during the year to apply
them.
- Yellowjackets / bees - Both may be seen visiting trees and shrubs for the honeydew produced by aphids and soft scales.
Information provided courtesty of Whitney Cranshaw, Department of Bioagricultural
Sciences and Pest Management, Colorado State University.
Photo: Judy Sedbrook
