Boxelder Bugs, Peach Twig Borer, Codling Moth
August 29, 2003
Peach, apple, and pear growers should keep an eye out for adult and nymphal populations of boxelder bugs. Significant populations have been spotted on peaches in Perry (Boxelder County). Aggregations of the adults were observed within the tree canopy. Adults can feed on leaf veins, petioles, fruit, and shoots. In Logan, nymphal boxelder bugs in riparian areas were observed, suggesting that there will likely be substantial feeding as the nymphs try to grow and mature into adulthood by winter (boxelder bugs overwinter as adults). If excessive numbers are seen in peach, apple, or pear orchards, it may be wise to apply a material with a short pre-harvest interval, such as Sevin (carbaryl, PHI: 3 days) , Lannate (methomyl, PHI: 4 days), Pounce/Ambush (permethrin, PHI: 7 days), or malathion (PHI: 7 days).
PEACH TWIG BORER:
Unharvested peaches are highly desirable feeding sites for twig borer caterpillars at this time of year. Most of the trees' shoots have set terminal buds and hardened off by now, forcing the young larvae to look to the fruit, which have ripened and become more appealing. Examine the fruit for signs of feeding damage (especially around the stem end, although the young caterpillars can burrow in anywhere). If the twig borer has been feeding, you should see tiny brown grains (frass) as well as some dry, crystallized "sap," and maybe a darkened area where fungus has also colonized the tissue. Trap catches have risen recently in Boxelder, Davis, and Utah Counties. Genola, Payson, Kaysville, Spanish Fork, and various locations in between may need to be treated sometime this weekend or early next week, IF there is a significant moth population and the fruit will be on the tree for more than another week. Cache Valley growers may need to treat later in the week.
According to Diane Alston, "the rule of thumb" for codling moth control is to maintain protection through the second week of September. Most growers likely treated in mid- to late-August, so depending on your harvest date, another treatment may be necessary next week to protect your crop through harvest. As always, be sure there is sufficient time to accommodate the PHI of the material used. Many moths continue to be caught, especially in Boxelder county. Continue monitoring your fruit and traps.
Precautionary Statement: All pesticides have benefits and risks, however following the label will maximize the benefits and reduce risks. Pay attention to the directions for use and follow precautionary statements. Pesticide labels are considered legal documents containing instructions and limitations. Inconsistent use of the product or disregarding the label is a violation of both federal and state laws. The pesticide applicator is legally responsible for proper use. Any mention of a pesticide brand in this document is not an endorsement by USU, and brand lists are not all-inclusive.