Based on the codling moth degree day (DD) model, emergence of second generation adults is nearly complete in Henderson County and locations at similar elevations (about 2,000 ft), and third generation adults are emerging in lower elevation orchards. Model predictions become less accurate later in the season, so pheromone trap captures are an important tool to help assess the need for insecticide applications at this time of the year. However, history shows that the potential for late-season damage is very low if problems (i.e., damaged fruit) have not been observed by the end of the second generation.

We are also approaching that time of the year when oriental fruit moth (OFM) can be an issue in some orchards. An application of sprayable OFM pheromone in mid August has been common among those not using full-season mating disruption, but pyrethroid use for BMSB has also controlled OFM. Hence, keeping an eye on OFM pheromone trap captures is important where pyrethroid use declines.

The brown marmorated stink bug adult emergence DD model predicts that first generation adults are now beginning to emerge in Henderson County and similar elevations. Over the next week, about 25% of the population will have emerged. In Cleveland County and similar elevations, about 50% of the generation has emerged, and this will increase to 75% over the next week. Over the past few years BMSB populations have declined in this region, and overwintering adult numbers have been low this year. Unfortunately we do not have a good estimate of the potential intensity of first generation adult populations, but hopefully we will have a better idea over the next couple of weeks.

Despite the unknown pest status of BMSB at this time, preventive control in the next week should be considered on the most susceptible cultivars, which include late-maturing cultivars such as Granny Smith, Pink Lady, and Rome. Conversely, cultivars harvested by the first week of September have shown low potential for BMSB damage, and the need for insecticide applications on those cultivars is questionable.

Pyrethroids remain the most effective and inexpensive insecticides for BMSB control. In general there is no noticeable differences in the efficacy of most recommended products (see below), with exception of bifenthrin (Brigade), which has shown longer residual activity than other products. Considering the wide range of preharvest intervals for recommended insecticides, this will surely be a key factor in product choice.

Insecticides recommended for brown marmorated stink bug on apples:

Learn more about southeastern apple insect pests at the Apple Insect Management page.

2024 Average Weekly Trap Captures

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.

2024 Accumulated Degree Days

About degree-day models

2024 Pest Population Trends