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How to Manage Pests

UC Pest Management Guidelines

Peachtree borer, location of infestation on tree.


Peachtree Borer

Scientific name: Synanthedon exitiosa

(Reviewed 6/06, updated 4/09)

In this Guideline:


Gum exuding from around the base of the trunk is evidence of a peachtree borer infestation. Larvae of the peachtree borer are white with brown heads. Adults are clear-winged moths with blue-black bodies that have yellow or orange bands across the abdomen. The adult peachtree borer may be found from June to September, with larvae present in the tree the rest of the year. There is only one generation each year. It is found mainly in coastal areas and in the northern San Joaquin Valley.


This wood-boring insect can successfully attack healthy trees. The larval stage bores into the crown and trunk of the tree and mines the cambial layer. If this occurs for several years, the tree may eventually become girdled and die.


Apply insecticides when adults emerge to help control peachtree borer adults. Pheromone traps are available to monitor adult emergence.

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

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, impact on natural enemies and honey bees, and impact of the timing on beneficials. When choosing a pesticide, also consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
  (Asana XL) 4.8–14.5 fl oz 2–5.8 fl oz 12 14
  COMMENTS: Apply as a directed trunk and scaffold limb spray. Thorough coverage of trunk and scaffolds is required.
B. ENDOSULFAN* 2.66–3.33 qt 0.66 qt 4 7
  (Thionex) 3EC
  COMMENTS: Apply with a hand spray gun to tree water or trunk from juncture of main scaffold limbs to soil line. Cover trunk thoroughly using enough liquid so it runs off to form a small puddle at base of tree. Two treatments are necessary to span the long emergence period of this insect in California. Make the first in mid-May, the second in mid-July. Hoe around trees to remove weeds or sucker growth that might interfere with spray coverage. Clear away any excess soil piled against tree during discing operations.
** For dilute applications, rate is per 100 gal water to be applied in 300-500 gal water/acre, according to label; for concentrate applications, use 80-100 gal water/acre, or lower if the label allows.
+ 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: 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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