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Larry Sagers Horticultural Specialist Utah State University Extension Service Thanksgiving Point Office © All Rights Reserved
**********Insect Advisory*********** CODLING MOTH: In much of Cache County and high-elevation sites elsewhere, the initial codling moth larval emergence most likely occurred last weekend (June 12th). The rest of northern Utah is experiencing peak egg-hatch, which is “rush hour” for codling moth larval emergence.
The bulk of the first generation eggs will hatch out during this time, and it usually lasts 2-3 weeks. Visit the codling moth phenology table to see current degree-day totals (check for your nearest location and then look in the column that says “DDs Since Biofix”): http://extension.usu.edu/cooperative/ipm/index.cfm/cid.645/tid.921/.
PEACH TWIG BORER: In the warmest sites (Salt Lake County), PTB populations are likely at or beyond 300 DDs. Most growers spray for PTB between 300 and 400 DDs. Most other sites in northern Utah have 4-10 days before they reach 300 DDs. Visit the PTB phenology table to check the projected developmental status of PTB in your area: http://extension.usu.edu/cooperative/ipm/index.cfm/cid.645/tid.924/. (Bear in mind that when the high temperature for a given day reaches the mid 80’s and the nighttime low hits the mid-50’s, you can expect 15-20 degree-days for the day.)
WESTERN CHERRY FRUIT FLY: As the cherries begin to yellow and take on a pink blush, they become soft enough for WCFF females to insert their eggs. Continue to keep trees protected, and be aware that rain events can shorten treatment intervals.
LYGUS AND OTHER CAT-FACERS: Keep an eye out for lygus bugs and stink bugs, particularly in orchards near open hillsides and alfalfa fields. Adult lygus bugs have been observed in peach canopies in Utah County. Their feeding damage causes cat-facing of peaches and apples. Sweeps of orchard groundcover or roadside vegetation will help determine if they’re present. Most broad-spectrum insecticides work well for these insects.
**********Disease Advisory*********** FIRE BLIGHT: Fire blight infections have been observed in Utah Co. apples and Davis Co. pears. Pruning out these strikes will remove the infection and reduce subsequent shoot blight infections.
PEACH LEAF CURL: Despite its rarity in Utah, this fungal disease of peaches is showing up in a few isolated instances. Please visit the USU Extension Photo Gallery for images of peach leaf curl: http://eureka.ext.usu.edu/admin/plugin.cfm?id=2&img=405&gid=53 . Fall and/or early spring applications of copper or chlorothalonil are good management approaches for this disease. Sanitation and cultural practices are ineffective.
