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Fruits
Volume 63 Number 14 Date 08/02/2018 BROWN MARMORATED STINK BUG - Nymphs are appearing on traps in Dane and Rock counties. For apple orchards where BMSB is known to be established, it is particularly important to be alert for late-season populations and fruit injury. Most BMSB feeding occurs at night, so the stink bugs may not be as noticeable during the day. In addition to their clear sticky traps, growers monitoring BMSB this season should also watch for BMSB adults near lights as an indicator of stink bug pressure. In eastern states where BMSB is a severe orchard pest, damage to apples has been misidentified as cork spot and/or bitterpit, disorders related to calcium deficiency. As populations of this pest continue to increase and spread in Wisconsin, on-site monitoring will be the best determinant of whether or not treatments targeting BMSB are necessary. An economic threshold for clear sticky panel traps is not yet available, but USDA-ARS Research Entomologist Dr. Tracy Leskey has specified a provisional threshold of 10 BMSB per week for black pyramid traps to apply an alternate-row-middle spray. She also notes that the occasional BMSB caught in traps may not warrant BMSB sprays and growers should wait for sustained captures. CODLING MOTH - Substantial flights (15-46 moths) continued in the past week in many cooperating orchards. According to Orchard IPM Specialist John Aue, the unusually large second-generation flights may be a result of the heavy rain diluting larvicide coverage during the first-generation treatment window in early June. Summer codling moth pressure is often a direct indicator of the efficacy of spring generation management programs. Monitoring of pheromone traps is recommended until the end of the month to determine the need for late-season CM control. Spot treatment may be appropriate for blocks where trap counts remain above the economic threshold of five moths per trap per week. An insecticide application is not necessary if trap counts do not exceed this action threshold. Growers are reminded to review pre-harvest intervals before making an application. APPLE MAGGOT - Emergence has peaked in all but the far northern counties. A high weekly counts of 22 flies per red sphere trap was reported from Gays Mills in Crawford County, while seven of 23 orchards registered economic captures of flies (1 fly per unbaited trap or 5 flies per baited trap). Apple growers are advised to maintain traps through the first week of September and continue apple maggot sprays as long as the flies are being captured and counts exceed established thresholds. -- Krista Hamilton, DATCP Entomologist 
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