How to Manage Pests

UC Pest Management Guidelines

Monitor the orchard early in the season as trees come into bloom to help detect potential pest problems early.

1. Sample the orchard ground cover for plant bug, stink bug, and katydid populations (view photos of ground cover pests).

2. Monitor trees for the presence of peach twig borers, fruittree leafrollers, or obliquebanded leafrollers, katydids, and western flower thrips (view photos). Examine flowers and leaves on 2- to 3-year-old branches located at head height on each of 50 trees as you walk through each varietal block. For peach twig borers and leafrollers, pull off a few flowers and examine for feeding, holes, or the presence of caterpillars. For katydids, spend about 30 seconds examining leaves for feeding damage. For thrips, examine a blossom from each tree by slapping it against your hand or a light yellow card; also dissect the flower and use a hand lens to look for the immature stages. Monitoring at this time will let you know the effectiveness of the dormant or bloom treatment and alert you to the need for additional treatment.

Pest	What to look for	Treatment threshold
peach twig borer larvae	At this time peach twig borers feed at the base of flowers where they bore into the calyx, creating small holes. They may also enter the tips of shoots causing them to wilt (see Shoot Strike Monitoring).	If any are present, a treatment is necessary at first flight.
fruittree leafroller, obliquebanded leafroller	Fruittree leafroller and obliquebanded leafrollers feed on blossoms as well as young foliage and begin to tie leaves together.	Thresholds have not been determined.
katydids	Katydid feeding consists of small holes in the center of young leaves.	If any of the leaves examined show signs of feeding, a treatment may be warranted.
western flower thrips	Immature thrips located in the blossoms.	If two blossoms out of 50 sampled have thrips, treat.

PUBLICATION

UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451
General Information
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to the insects and mites section:
R. E. Rice, Kearney Agricultural Center, Parlier

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