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How to Manage Pests
UC Pest Management Guidelines
Apricot
Peachtree
Borer
Scientific name: Synanthedon exitiosa
(Reviewed 11/07,
updated 11/07)
In this Guideline:
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Peachtree borer eggs are laid during the summer on the bark at the
base of trees. Larvae overwinter in the tree trunk near the soil line. They
feed in the crown area and burrow up into the tree. At maturity, a larva is
about 1-inch long, and has a light-colored
body and a dark head. In late spring, larvae pupate near the entrance of their
burrows or in the soil. Adults emerge from May through September; they are steel blue to black clearwinged
moths with a 1-inch wing span.
DAMAGE
Peachtree borers can girdle and kill young trees. Older trees can
withstand the damage unless there are many larvae or the tree is attacked
several years in a row.
Look for the presence of frass and gum at the bases of trees when
monitoring orchards in spring. Also check trees in fall for signs of peachtree
borer activity. At this time, you can kill larvae by carefully using a knife or
wire to probe the trunk. Mark infested trees that you find, and return to treat
them the following spring with insecticide by spraying the trunk from the
scaffold to the soil line. Apply the insecticide with a hand-held sprayer to
the tree trunk from the juncture of the main scaffold limbs to the soil line.
Cover the trunk thoroughly, using enough spray material so it will run off to
form a small puddle at the base of the tree. Use from 0.5 to 1.5 gallons per
tree, depending upon the size of the trunk. Remove suckers and pull soil away
from the base of the tree before treating. Two applications are recommended to
protect during the prolonged period when adults are active, one in mid-May when
adults are first detected and one in the middle of July. Be careful to observe
preharvest intervals and use low-pressure sprays to avoid contaminating fruit.
You can use pheromone traps to monitor adult
emergence. They are useful for determining the presence of peachtree borers.
(The pheromone lure may be listed as peachtree borer or greater peachtree
borer.) Place the traps in trees no later than late April and maintain them
through September, changing lures at the recommended interval (usually one
month) and the trap bottoms when they become dirty and lose stickiness. If they
catch large numbers of male peachtree borers (approximately 10 or more per
week), return later and examine the trees carefully for signs of feeding
activity. Be sure to properly identify the moths that are trapped; other
clearwing moths may be attracted by the peachtree borer pheromone.
Keep tree bases free of vegetation to help reduce problems with
peachtree borer, especially in the Central Valley. Heat and dryness reduce the
survival of eggs and larvae.
| Common name |
Amount to Use** |
R.E.I.+ |
P.H.I.+ |
| (trade name) |
(conc.) |
(dilute) |
(hours) |
(days) |
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| When choosing a pesticide, consider information relating
to the impact on natural enemies and honey bees and environmental impact.
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| A. |
ESFENVALERATE* |
| |
(Asana) XL |
4.8–14.5 fl oz |
2–5.8 fl oz |
12 |
14 |
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MODE OF ACTION GROUP NUMBER1: 3 |
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COMMENTS: Apply as a directed trunk and scaffold limb spray. Thorough coverage of trunk and scaffolds is required. |
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IMPORTANT LINKS
UC IPM Pest Management Guidelines: Apricot
UC ANR Publication 3433
Insects and Mites
W. W. Coates, UC Cooperative Extension, San Benito County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
K. A. Kelley, UC Cooperative Extension, Stanislaus County
J. L. Caprile, UC Cooperative Extension, Contra Costa County
Acknowledgment for contributions to Insects and Mites:
L. C. Hendricks, UC Cooperative Extension, Merced County
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