Attract-and-Kill Strategy Shows Promise for Managing Brown Marmorated Stink Bugs

By Rob Morrison, Ph.D.

Tell your pesky stink bugs to bring all their friends to a party, with some of their favorite fruit provided—but at a cost: their lives.

Alright, so perhaps don’t tell them that last bit. We can keep that as an after-the-fact surprise!

A study led by researchers at the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) has shown positive results of a proof-of-concept test of an attract-and-kill method to manage the brown marmorated stink bug (Halyomorpha halys) in apple orchards.

The concept behind attract-and-kill is straightforward: One simply puts out a large amount of the species’ aggregation pheromone along with pheromone synergist methyl decatrienoate (think of it like calling all your friends and telling them there’s a bunch of free food at your house), which attracts stink bugs to a specific area. Then, a grower can spray that area with an insecticide to remove the individuals from the feeding population. The advantage of this system is that you can target sprays to one small area of the orchard (e.g., a 90 percent reduction in area sprayed) compared with conventional management, which typically involves spraying an entire block of apples. This leaves large swathes of the apple block as refuge for natural enemies and pollinators.

This project, funded by the Sustainable Agriculture Research and Education program, was led by Tracy Leskey, Ph.D., at USDA-ARS Appalachian Fruit Research Station and involved researchers at Penn State University, Rutgers University, the University of Maryland, Virginia Tech, and West Virginia University. Results of the study are presented in a report, on which I served as lead author, published in July in Pest Management Science.

Attract-and-kill was implemented on 10 farms in five Mid-Atlantic states (Maryland, New Jersey, Pennsylvania, Virginia, and West Virginia) over two years. Attract-and-kill resulted in a two- to three-fold decrease in the frequency and severity of stink bug damage in apples compared with grower-standard techniques, or else had equivalent levels of damage. In total, at 32 percent of the attract-and-kill baited trees, more than 10,000 stink bugs were killed over the two years.

The attract-and-kill method for pest management is straightforward: Use a target species’ aggregation pheromone to attract large numbers of the pest to a specific area. Then, a grower can spray that area with an insecticide to remove the individuals from the feeding population. The advantage of this system is that one small area can be sprayed, rather than an entire orchard or field. These brown marmorated stink bug (Halyomorpha halys) were targeted in a study of the attract-and-kill method led by researchers at the USDA-Agricultural Research Service. (Photo credit: Rob Morrison, Ph.D.)

This tree was baited to attract brown marmorated stink bug (Halyomorpha halys, or BMSB for short) in the course of a study on the attract-and-kill method for management of the pest in apple orchards. Attract-and-kill sites were sprayed on a weekly basis during the growing season, which spared much of the rest of the orchard from insecticide sprays for BMSB, a primary pest of concern in eastern apple production. (Photo credit: Rob Morrison, Ph.D.)

Rob Morrison, Ph.D., a Research Entomologist at the USDA-Agricultural Research Service, used harmonic radar to track the movement of tagged brown marmorated stink bugs (Halyomorpha halys) in the course of a study on the attract-and-kill method for management of the pest in apple orchards. (Photo credit: Rob Morrison, Ph.D.)

In a study of the attract-and-kill method for management of the brown marmorated stink bug (Halyomorpha halys), some of the insects were tagged with a small antenna and tracked with harmonic radar, to better understand their movement. (Photo credit: Rob Morrison, Ph.D.)

In a study of the attract-and-kill method for management of the brown marmorated stink bug (Halyomorpha halys), monitoring stations were set up around the orchard to better understand the size of the “party zone” into which the pest would be attracted by the pheromone bait used. (Photo credit: Rob Morrison, Ph.D.)

The brown marmorated stink bug (Halyomorpha halys) is a major pest of apple orchards in the United States (among many other crops the generalist pest targets). When feeding, it pierces the skin of the apple, which leads to internal damage such as shown here. (Photo credit: Rob Morrison, Ph.D.)

One concern might be the build-up of secondary pests in the orchards, but over the course of the study secondary pests such as mites and woolly apple aphids were found to be similar between the attract-and-kill and standard management types. The more important concern is the cost of the attract-and-kill system compared to standard techniques. Indeed, at the moment, attract-and-kill is not economically feasible for growers. However, the study employed experimental lures at a time when only one company was producing them. Since that point, more companies have started producing lures through new biosynthetic pathways that are rapidly decreasing costs.

In addition, there are many opportunities to optimize the attract-and-kill system to increase the cost/benefit ratio. For example, the study conservatively placed attract-and-kill sites 50 meters (164 feet) apart, but it is likely they could be spaced farther apart, resulting in less pheromone needed per apple block. Meanwhile, 840 milligrams of aggregation pheromone was used per site, but it is possible that less pheromone is needed to achieve the same level of control.

More generally, it may be possible to move away from fixed sites by having a sprayable pheromone that dissipates as insecticide efficacy decreases, thus employing temporary attract-and-kill sites. Conversely, the need for insecticides could be eliminated completely by using long-lasting insecticide treated nets as the killing agent; this approach also has the added benefit of reducing labor needs as well.

Overall, the study presented a successful proof-of-concept of the attract-and-kill technique. The use of this technique successfully managed brown marmorated stink bugs relative to grower-standard methods. Going forward, the system needs to be optimized to increase economic feasibility, but attract-and-kill presents enormous promise to manage brown marmorated stink bug in a sustainable way in the near term.

Rob Morrison, Ph.D., is a Research Entomologist at the USDA-Agricultural Research Service, Center for Grain and Animal Health Research, in the Stored Product Insects and Engineering Research Unit, in Manhattan, Kansas, and the 2017-2018 chair of the Entomological Society of America’s Early Career Professionals Committee. Web: www.ars.usda.gov/pa/cgahr/spieru/morrison. Twitter: @morrisonlabUSDA. Email: william.morrison@ars.usda.gov