How to Manage Pests
UC Pest Management Guidelines
(Reviewed 6/10, updated 6/10)
In this Guideline:
Preharvest fruit sampling will alert you to the need to treat before harvest. (Be sure to check the preharvest interval of the pesticide if treatment is necessary.) Monitor weekly beginning at color break (when nectarines start to turn reddish).
How to Sample (view preharvest damage photos for identification)
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.
Before the sorting process begins, examine 500 to 1,000 randomly selected fruit from harvest containers. 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, katydids, and thrips as well as brown rot, rust, and scab.
Look for the presence of:
Record 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, katydids, thrips, and note any indication of rust, brown rot, and scab. Record results for harvest sample.
UC IPM Pest Management Guidelines:
W. J. Bentley (Crop
Team Leader), UC IPM Program, Kearney Agricultural Center, Parlier
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