How to Manage Pests
UC Pest Management Guidelines
In this Guideline:
Cankerworm larvae have three pairs of prolegs.
They are greenish above, with three narrow, whitish stripes and one yellow
stripe along the side of the body; underparts are light green. Cankerworms
frequently stand on the posterior pair of prolegs in such a way
that they resemble a small twig. Cankerworms pass the winter in the egg stage.
Caterpillars hatch and feed on leaves in spring and summer, then pupate and
develop into moths in fall. There is one generation per year.
The larvae are primarily leaf feeders, tending to
skeletonize leaves. Occasionally they feed on young fruit by biting deep holes,
which later heal, but leave large scarred depressions similar to the injury
caused by green fruitworms.
Bloom time treatments for peach twig borer will
help to keep these leaf-eating caterpillars in check. If cankerworms are
detected on small trees, infested twigs can be cut out and destroyed. View photos of caterpillars that are present at bloom for identification.
||Amount to Use**
choosing a pesticide, consider information relating to impact on natural enemies and honey bees, impact of the timing on beneficials, and environmental impact Not all registered pesticides are listed. Always read label of product being used.
||BACILLUS THURINGIENSIS ssp. KURSTAKI#
ACTION GROUP NUMBER1: 11.B2
Make 2 applications during bloom: the first between popcorn and the beginning of bloom and the second
7–10 days later, but no later than petal fall. Compatible with fungicide sprays, and can be
tank mixed with them. Good coverage is essential. Ground application using a
concentrate rate (80–100 gal water maximum) is preferred. If aerial
applications must be made because conditions do not permit ground
application, a concentrate rate (5 gal or less) is preferred. Fly material on
at a height of about 20 feet over the canopy using appropriate nozzles to allow better deposition on the tree tops.
UC IPM Pest Management Guidelines: Prune
UC ANR Publication 3464
Insects and Mites
C. Pickel, UC IPM Program, Sutter/Yuba counties
F. J. A. Niederholzer, UC Cooperative Extension, Sutter/Yuba counties
W. H. Olson, UC Cooperative Extension, Butte County
F. G. Zalom, Entomology, UC Davis
R. P. Buchner, UC Cooperative Extension, Tehama County
W. H. Krueger, UC Cooperative Extension, Glenn County
Acknowledgment for contributions to Insects and Mites:
W. O. Reil, UC Cooperative Extension Solano/Yolo counties
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