During the last couple of weeks, we have started to observe higher numbers of brown marmorated stink bug (BMSB) adults and nymphs collected in BMSB monitoring traps. Traps placed on or under trees located on the border of woods as well as traps placed in the first row of orchards, which rarely collected stink bugs earlier this season, now are capturing BMSB nymphs and adults. Since not every orchard is experiencing the same BMSB pressure, cautious scouting and monitoring of the vegetation surrounding the orchard should be very helpful in deciding if special stink bug control treatment(s) is necessary.
It is important to remember that the absence of stink bugs during the season, does not guarantee that they will not become abundant in the orchard just before the harvest. BMSB is not an orchard “resident pest” and whatever management tactics were utilized to control BMSB during the season in any particular block, cannot guarantee or prevent new individuals from infesting or re-infesting the site just prior to the harvest. It is still not too late to deploy BMSB monitoring traps into your orchard – at least in the areas of possible highest BMSB pressure.
The BMSB monitoring lures and traps from AgBio Inc. or Trece Inc. are available either directly from the manufacturer or specialty stores. It is important to remember that while BMSB traps will collect high numbers of targeted insects, they are only intended to help to decide if special management is needed, but monitoring traps will not control stink bugs.
The incessant feeding of nymphs and adults could potentially cause significant injury especially to later maturing apple cultivars. Fresh injuries from stink bug feeding are initially almost undetectable, but after 10 to 14 days, the injury (i.e., corking) becomes easily visible. If BMSB feeding occurs just prior to harvest, it is quite possible that at harvest time, affected fruit will exhibit no apparent signs of injury, but the characteristic depression (corking) on the fruit surface will develop during the storage time. Late-season feeding can be very intensive, as adult stink bugs are trying to accumulate enough resources to survive the winter.
Insecticides will control only the individuals present in the orchard at the time of the application (i.e., direct contact activity), but they will not stop arriving BMSB adults from at least initially probing the fruit and, unfortunately, each probing equals new injury. Most of the insecticides provide only from 7 to a maximum of 12 days protection after the application (higher rates of product usually provide longer residual activity).
Figure 1. Container type BMSB monitoring trap from Ag-Bio Inc. (left) and sticky trap from Trece Inc. (right). Photo: G. Krawczyk, Penn State
Figure 2. Brown marmorated stink bug adult and nymph (left) and green stink bug adult (right) on apples. Photo: G. Krawczyk, Penn State
The following list includes insecticides with good activity against BMSB adults and nymphs, as well as the pre-harvest (PHI) information for each product:
- Assail 30 SG (acetamiprid, IRAC Group 4A) – 7-day PHI on pome and stone fruit, no more than 32.0 oz of formulated product per acre per season;
- Brigade WSB, Bifenture EC, Bifenture 10DF (bifenthrin, IRAC Group 3) – products are registered under Special Section 18 Emergency Exception Registration for the 2021 season; 14-day PHI on apples, peaches, and nectarines.
- Belay (clothianidin, IRAC Group 4A) – 7-day PHI on apples and pears; 21-day PHI on peach, no more than 0.2 lb AI per acre/per season is allowed.
- Danitol (fenpropathrin, IRAC Group 3) – 14-day PHI on apples and pears; 3 days on stone fruit. No more than 0.8 pounds of AI is allowed per acre/season.
- Admire Pro (imidacloprid, IRAC Group 4A) and – 7-day PHI on pome fruit, 0 days PHI on stone fruit, no more than 0.5 lb AI per season;
- Leverage (imidacloprid mix with beta-cyfluthrin, IRAC Groups 3 and 4A) – 7-day PHI on pome and stone fruit, with no more than 0.044 lb AI per acre of beta-cyfluthrin and/or 0.088 lb AI per acre of imidacloprid.
- Warrior II with Zeon Technology, Taiga Z (lambda-cyhalothrin, IRAC Group 3) – 21-day PHI on pome fruit, 14-day PHI on stone fruit.
- Lannate (methomyl (IRAC Group 1A) – 14-day PHI on apples; 7 days on pears; 4 days on peaches; 1 day on nectarines (PA only). On apples no more than 4.5 pounds of AI/acre is allowed, on peaches no more than 5.4 pounds of AI per acre/season; on pears no more than 1.8 pounds of AI per acre/season.
Please note that for this 2021 season, insecticides Venom or Scorpion (with active ingredient dinotefuran) are not legal for use against brown marmorated stink bug as they did not receive the Section 18 Emergency Use Exemption for 2021.
Insecticides such as Pyganic (natural purethrum), Azera (natural pyrethrum plus azadirachtin), or Venerate (Burkholderia spp) which are approved for use in organic production will provide some limited direct efficacy against BMSB adults and nymphs, however, their residual activity is much shorter from synthetic insecticides and for effective control of BMSB multiple, frequent applications will be necessary.
– Grzegorz (Greg) Krawczyk, Penn State University Extension Tree Fruit Emtomologist
