Drones Deliver Sterile Insects as Biocontrol

[Audio of 1960’s announcer:] Six. Five. Four. Three. Two. One. Zero. All engines running. Liftoff. We have a liftoff.

This launch isn’t shooting for the moon or a distant planet. No rocket boosters are needed. And the passengers inside? Insects.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “We developed, in collaboration with USDA, a drone-based system for releasing sterile insects.”

On a September day in western Michigan, the insects traveling during this routine drone launch by M3 Agriculture Technologies are codling moths, the bane of existence for many pear and apple orchard owners.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “Codling moth is really the worm in the apple. It’s the primary pest. It has always been a nuisance for growers for the last 200 years in North America. It’s a predominant pest worldwide. I think the only place where codling moth is not an issue, has not established, is in Japan, in some parts of Asia.”

Codling moths have long been a foe at Hayden Farms of Pasco, Washington, but when the apple and cherry producers switched a half dozen years ago to organic apple practices, meaning synthetic pesticides were no longer an option, they struggled to keep control.

Denny Hayden, Hayden Farms, Pasco, Washington: “The major pest in apples, by far, is codling moth. When we first converted, we were clean coming from conventional to organic, we didn’t have any codling moth problems. We had a neighbor that was organic and kind of got in trouble with the farm and his control went to heck. A lot of problems, and those problems drifted over to us….We tried every means possible to control codling moths.”

Hayden says they ultimately needed an answer beyond just natural oils and an insect virus spray. Those worked but oils can only be applied a few times before harming the trees, and the viral spray needed to be reapplied repeatedly, driving their pesticide spending up. The viral spray also had to be consumed by the insects, meaning they would leave tiny bite holes in the fruit known as stings.

Inspired by Washington State University’s research into sterilized insects as biocontrols in orchards, Hayden decided to give it a try, hiring M3.

Denny Hayden, Hayden Farms, Pasco, Washington: “We were really shocked. The first year we saw real good results. We still had some stings that first year with it. Since then, we have really been very clean. This year, I mean I might have seen a couple stings all season in 125 acres.”

Although drone-delivery of insects is relatively new, sterile insect technique, or SIT, is not. SIT is a type of biological control, an alternative or supplement to chemicals, when managing agricultural pests like the codling moth.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “The insects that we release are sterilized. They are sterilized with ionizing radiation and it damages their DNA to the point where they’re still viable, as far as they are able to fly and able to act as insects, but when they mate with another insect, with a native insect that’s out in the target environment, they will lay an infertile egg.”

USDA has been using sterile insect strategies for decades, most notably when airplanes dropped sterilized pink bollworms, an insect that once devastated cotton crops all over the South. In 2018, USDA announced it had successfully eradicated pink bollworm, present in the U.S. ecosystem for more than a century.

Earl Andress, USDA-APHIS: “Sterile insect technology is not a stand-alone technology in most cases. In the pink bollworm, we had a variety of technologies that we used… We hit pink bollworm with everything we had…You have to have a thorough knowledge of the insect’s biology, its field behavior, and how it interacts with the host and all its natural enemies.”

After being awarded a grant, M3 began working with USDA in 2014 on developing a rapid-response system in case of any small breakouts of pink bollworm.

Four years later, the Dayton, Ohio-based company got to work figuring out how to safely ship and store sterilized Mexican fruit flies, lady beetles, codling moths and other insects from insect rearing facilities before attempting to drop sometimes-reluctant bugs from drones into treetops. The company designed its own drones and release devices.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “We went up to Washington and started releasing sterile codling moth… and we treated 50 acres. In 2019, we treated 1,200 acres, and that was our first year of commercial sales. Now, we are at 4,000 acres in 2022 and growing quite nicely.”

The company, now with 10 employees, has moved away from its previous dependence on government grants. Besides contracts in Washington, M3 now has customers in California, Idaho and Michigan. Part of the reason for the growing enthusiasm among producers is that insects, just like weeds, develop resistance to pesticides.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “For the majority of crops, especially apples and pears, there’s no new chemical formulations coming online, there’s no more being developed. It takes generally ten years of a long pipeline, millions of dollars to develop different chemical formulations… we think that methods such as biocontrol using insects and such: those are going to become more and more popular.”

Eoin Davis, USDA-APHIS: “I think there are a lot of options with SIT. And I think it depends a lot on the pest you are talking about, and the crop, and just the setting for exactly where and what you have to work with.”

Various studies estimate the value of the natural biological control of native pests in U.S. crops at between $1.7 billion and $5.5 billion.

A Canadian facility is the only large-scale insectary rearing sterilized codling moths.

Krompetz expects demand to grow for other insects, especially predatory mites that feed on twospotted spider mites, which are harmful to crops like hops and strawberries. Also, green lacewings, which eat other harmful aphids, show promise for many specialty crops, including fruits, nuts and marijuana.

Dustin Krompetz, Chief Operating Officer, M3 Agriculture Technologies: “The big issue that we face is the supply of insects long-term.”

By Colleen Bradford Krantz, colleen.krantz@iowapbs.org