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How to Manage Pests
UC Pest Management Guidelines
Peach
Fruit
Sampling
(Reviewed 3/06,
updated 3/06)
In this Guideline:
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PREHARVEST FRUIT SAMPLES
Preharvest fruit sampling will
alert you to the need to treat before harvest. (Be sure to check the preharvest
interval of the insecticide if treatment is necessary.) Start taking fruit damage samples every other week around color break (when peaches begin to turn reddish).
How to Sample (View
preharvest damage photos for identification)
Examine 100
to 200 randomly selected fresh fruit on the tree (10-20 fruit on 10 trees) for
damage caused by:
Evaluate the
fruit by looking at it on the tree and rotating it slightly. Record on a preharvest sampling form the number of fruit infested
by larvae, type of larvae present or if there are no larvae present, whether
the damage is surface feeding only or if the larvae penetrated the fruit. Also,
record the number of fruit with live San Jose scale and parasitized San Jose
scale, the presence of sunken pithy areas indicating plant bug, stink bug, or
katydid damage, and the presence of rust or brown rot.
FRUIT EVALUATION AT HARVEST
Take a fruit damage sample at harvest to assess the effectiveness of the current year's IPM program
and to determine the needs of next year's program; be sure to keep a record for
each block.
How to Sample
(View harvest damage
photos for identification)
Before the sorting
process begins, examine 500 to 1,000 randomly selected fruit from bins. Plan to
sample 500 fruit for each variety unless unexpected damage is discovered, in
which case increase the sample size up to a maximum of 1,000 fruit in order to
thoroughly assess the damage. Distinguish damage caused by peach twig borer,
oriental fruit moth, and leafrollers, San Jose scale, stink bugs, plant bugs,
and katydids as well as brown rot, rust, and scab.
Look for the presence of:
- Larvae or larval feeding from peach twig borer, oriental fruit moth, or other caterpillars.
-
Peach twig borer: shallow feeding holes. Over time
these may appear as scabs.
-
Oriental fruit moth: often small entry holes that may
be difficult to see, especially if brown rot has invaded the site.
-
Leafrollers: tunneling into fruit; shallow holes or
grooves in the fruit surface.
- Live or parasitized San Jose scale and halos or spots on the fruit surface.
- Scabs, pits caused by stink bugs, plant bugs, and katydids.
- Fruit rot. In many cases, this damage may occur in
conjunction with peach twig borer or oriental fruit moth damage or other
physical injury.
- Rust lesions, which can resemble stink bug damage but can
be distinguished by the presence of spore masses in the lesions, and lesions
are often surrounded by halos.
- Scab lesions on fruit are dark spots and may have green or yellow halos. They are
most commonly on the upper surface and may merge to form large blotches.
Record on a harvest
monitoring form the number of fruit infested by larvae, type of larvae present or, if there are
no larvae present, whether damage is surface feeding only or if the larvae
penetrated the fruit. Record the number of fruit with live San Jose scale, or
parasitized San Jose scale. Record the number of fruit with damage caused by
stink bugs, plant bugs, and katydids, and note any indication of rust, brown
rot, and scab.
![[UC Peer Reviewed]](/IMAGES/logo-ucpeerreviewed.jpg)
UC IPM Pest Management Guidelines: Peach
UC ANR Publication 3454
General Information
C. Pickel, UC IPM Program,
Sutter/Yuba counties
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
J. K. Hasey, UC Cooperative Extension, Sutter/Yuba counties
K. R. Day, UC Cooperative Extension, Tulare Co.
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