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How to Manage Pests

UC Pest Management Guidelines

American plum borer adult


American Plum Borer

Scientific Name: Euzophera semifuneralis

(Reviewed 1/08, updated 1/09)

In this Guideline:


The adult moth is gray with a wing expanse of 0.75 to 1 inch (19–25 mm) and brown and black markings on the wings. Adult females lay eggs near where callous tissue has developed, such as at pruning wounds, crown galls, or scaffold crotches. Larvae bore into the tree to feed on vascular tissue. Mature caterpillars are dusky white or pinkish and are about 1 inch long. American plum borer overwinters in a protective cocoon spun in a sheltered location on the tree; pupation takes place in spring. There are three to four generations each year.


Larvae attack soft, spongy, calluslike tissue, which occurs at graft unions, tree wounds, and in olive knots. They can continue to feed into normal tissue, girdling limbs, which can cause small branches to break. Gummy frass and liquid exudate may occur around injured wood.


Monitor trees in spring and summer for frass and gum pockets. The borer can be detected by brownish frass and webbing at feeding sites. If larvae are present, remove and destroy infested wood if possible. If wood cannot be removed, spray trees with a hand held sprayer from one foot above the scaffold crotch to one foot below, two to three times during the growing season. The first application should be mid- to late April and subsequent applications at 6-week intervals. Efficacy is improved if the trunk is painted immediately following a trunk spray with a latex paint to protect against sunburn. The paint helps to preserve the insecticide and give protection over a longer period of time.

Common name Amount to Use** R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact. Not all registered pesticides are listed. Always read label of product being used.
  (Sevin) 80S 2.6–6.25 lb 12 14
  (Sevin) XLR Plus 2 qt 12 14
  COMMENTS: Do not exceed 6.25 lb carbaryl 80S/acre/year or 10 lb carbaryl XLR Plus/acre/year.
** Amounts per 100 gal water (except where otherwise stated), using 400-500 gal solution per acre.
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Olive
UC ANR Publication 3452
Insects and Mites
F. G. Zalom, Entomology, UC Davis
P. M. Vossen, UC Cooperative Extension, Sonoma County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
M. W. Johnson, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
G. S. Sibbett, UC Cooperative Extension, Tulare County
L. Ferguson, Pomology, UC Davis

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