Source: NCSU COOPERATIVE EXTENSION, 7/2/19


The insect pests of primary concern at this time are second generation codling moth and first generation brown marmorated stink bug (BMSB), but the need for insecticidal control is dependent on location (i.e., mountain versus piedmont locations).

Codling Moth: In higher elevation orchards such as Henderson County and other locations >2000 ft., codling moth degree day (DD) accumulations since biofix are about 1350 DD, compared to about 1720 DD in Cleveland County. The ideal timing for an insecticide against second generation codling moth in orchards NOT using mating disruption is about 1450 DD. Based on predicted temperatures, 1450 DD in Henderson County will occur on Saturday or Sunday (July 6 or 7). Hence, it would probably be wise to include an insecticide against codling moth in your next spray, especially if spraying is occurring at 14-day intervals. If an effective insecticide application against codling moth has not yet been made in lower elevation orchards, one should be made as soon as possible.

In orchards using mating disruption for codling moth, there is usually no need to apply an insecticide against the second generation. Additionally, in orchards not using mating disruption, but which have very low codling moth populations (based on low pheromone trap captures and no evidence of damage by the first generation), a codling moth insecticide can be delayed until trap captures reach 3 to 5 moths/week.

Brown Marmorated Stink Bug: The greatest threat of BMSB damage to apples is by first generation adults, which generally emerge in mid July and early August in piedmont and mountain areas, respectively. The timing of emergence can be predicted quite accurately by knowing when eggs were first laid by overwintering adults. By caging overwintering adults, we were able to detect first egg laying on May 7 in the piedmont and May 15 in Henderson County. Development from egg to adult requires 540 cumulative DD, and as of today total DD accumulations are 524 in the Piedmont (Cleveland County) and 356 in the Mountains (Henderson County). Based on temperature forecasts, 540 DD is predicted to occur on July 5 in Cleveland County and July 23 in Henderson County.

Hence, a spray for BMSB in piedmont locations should be considered later this week or next week. In the mountains, there should be no need for BMSB sprays for at least 3 weeks.

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