Oct 7, 2016BMSB still damaging Michigan fruit
This is the ninth and final report for 2016 of the Michigan State University Extension brown marmorated stink bug monitoring network. Last week, 29 nymphs and 808 adults for a total of 837 brown marmorated stink bugs were captured from 96 traps at 30 sites. With 42 percent of traps catching brown marmorated stink bugs this week, and nearly double the number caught, it is clear brown marmorated stink bugs are very active. This week was also the first time this season we caught brown marmorated stink bugs at orchards in southeast Michigan.
The majority of brown marmorated stink bugs caught in traps continue to be from Berrien (apple, grape, peach and urban), Kent (apple), Ottawa (apple), Saginaw (urban) and Van Buren (grape) counties. In addition, MSU Extension fruit educators have received calls and emails about damaged apples harvested within the last couple weeks. We also know that brown marmorated stink bugs are aggregating on the sides of homes and other structures in the process of seeking shelter overwinter.
In this final report of the season, we are including some important information for fruit growers who have late-season apples and grapes yet to be harvested.
What to do if you still have late variety apples to harvest in 2016
Brown marmorated stink bug nymphs and adults can cause damage in fruit and vegetable crops, but the damage will not be detected until weeks or even months later, especially in the case of fruit that is stored before being sold. In apples, damage to fruit from brown marmorated stink bug feeding can be confused with several disease or nutrient deficiencies, so it is important to involve your local MSU Extension fruit educator to help determine what caused the damage or send samples to MSU Diagnostic Services.
While brown marmorated stink bugs are fairly easy to identify and distinguish from native stink bugs, they can be highly cryptic in orchards. They prefer the tops of trees and their coloring exactly matches tree trunks. Traps are easy to deploy and check, but the area of influence for a single baited trap appears to be relatively small, and not terribly efficient. Therefore, it is important to place them near the crop, and if using a Rescue brand trap, make sure the fins of the trap touch the trunk or post so nymphs are able to crawl up into it.
It is also important to combine trapping with other sampling methods such as jarring of upper branches of fruit trees over beating trays in orchard edges close to woodlots. Apple orchards adjacent to peach orchards are considered to be at high risk for brown marmorated stink bug feeding injury, because peaches are highly favored by brown marmorated stink bugs.
If you have apples that are still a couple weeks away from harvest and you have harvested early-season apples in adjacent orchards showing signs of damage, you may want to apply a full cover of an insecticide that is rated as being excellent against brown marmorated stink bugs below (Table 1). This would be considered a “rescue” treatment meant to prevent further injury from occurring this season.
For next season in apples
Keep records of where damaged fruit occurred on your farm this season – those will be the orchards to target with the following measures. Timed to occur with second generation codling moth, orchards that are at risk of brown marmorated stink bug damage should receive a full cover of an insecticide that works on codling moths and brown marmorated stink bugs, making sure the tops of the trees are well covered. Monitoring with pheromone-baited traps will help determine population pressure and whether follow-up applications every seven days with a perimeter spray until harvest are needed.
For next season in peaches
Monitor peaches beginning mid-late May, especially along wood edges. Weekly border sprays on five- to 10-acre plots (crop border plus first full row) have been shown to be an effective strategy in New Jersey. Dispersal to peaches can be initially monitored using pheromone traps placed at the edges. Initiating sprays when bugs are first detected has not been evaluated, but might be an appropriate timing. Peaches on the interior should be monitored for injury or bug presence. If brown marmorated stink bugs are detected on the interior, a full block spray should be done.
What to do in grapes
Feeding by brown marmorated stink bugs can injure wine and juice grapes, but the primary concern is presence of the stink bugs during crush, which may taint the juice. A single application of a pyrethroid insecticide prior to harvest will remove bugs hiding in clusters, but be sure to check with your winemaker or processor before spraying close to harvest, and be sure to only use products with short pre-harvest intervals. As in other crops, brown marmorated stink bugs have higher populations on the edge of vineyards, so this knockdown treatment may be restricted to the crop edge.
About the brown marmorated stink bug monitoring network
Traps were checked at more than 80 sites for brown marmorated stink bug nymphs and adults using pyramid or Rescue style traps baited with commercial lures. Counties being monitored for brown marmorated stink bugs in 2016 were Allegan, Antrim, Benzie, Berrien, Genesee, Grand Traverse, Ingham, Ionia, Kalamazoo, Kent, Lapeer, Leelanau, Lenawee, Livingston, Macomb, Monroe, Oakland, Oceana, Ottawa, Saginaw and Van Buren. Traps were set up near apple, peach, pear, sweet and tart cherry, blueberry, grape, raspberry, strawberry, a variety of vegetable crops and at several urban locations considered to be hotspots.
For more information about management strategies in fruit, please refer to the MSU Extension Bulletin E0154, “2016 Michigan Fruit Management Guide.” To learn more about how to monitor for brown marmorated stink bugs, distinguish it from other similar-looking stink bugs and which plants it favors, visit MSU’s Brown Marmorated Stink Bug website.
Source: MSU Extension
– Julianna Wilson, Larry Gut, Rufus Isaacs, MSU Extension