One future of pest control: Grow and release swarms of sterile male insects

Low cost and brutal effectiveness. That pretty much sums up why chemical insecticides are the dominant way to keep insects from nibbling away at crops. Yet many of these chemicals are facing growing regulatory, scientific and media backlash. Recent research findings point to collateral damage to non-invasive, ecologically vital species of plants, insects, fish, and animals with bees as a high profile example. From another vantage point, many consumers are wary of the potential side effects to eating food that has been doused in complex, ancient Greek sounding substances like chlorpyrifos or carbaryl.

That leaves large chemicals producers like Bayer in a race to come up with ever more sophisticated toxicology — lethal only to the species considered pests; harmless to other species who chance across it; affordable and versatile enough for the world’s farmers to use it in a timely and judicious fashion. This is not an easy race to run, and it is made even less so by an insects’ evolutionary ability to develop resistance — or just by its knack for burrowing deep enough into a crop to avoid the mists of deathly sprays. Worse still, new chemicals are not something you can just develop, distribute, and hope for the best; each new variety requires years of tests and approvals.

Swarms of sterile males

So, the continued dominance of chemical insecticides is far from unquestioned — and the widening neonicotinoids ban across the European Union is a good illustration of how some are getting phased out already. But, if insecticides like these get phased out, what could come instead? One answer is … the insects themselves. Namely, the farming and dispersal of thousands and thousands of sterile males.

“The way it works is you rear the pest insect in a lab, separate out the males and sterilise them; they then go out into the wild and mate with the females, who no longer produce any offspring,” Glen Slade tells AFN, describing a process known as the Sterile Insect Technique (SIT).

While Slade was quick to concede that SIT has already been in use for crop protection for decades already, he said that his UK-based company BigSIS has used robotics and artificial intelligence to “reinvent the process,” making it far cheaper and more effective. “It’s using a proprietary X-ray-based sterilisation method,” he said, which leaves batches of sterile males fitter and “able to compete” with their wild, fertile male rivals for female affection.

Slade, who is the founder and CEO of BigSIS, said his company is building out a platform technology that provides pest control-as-a-service, working on a broadening portfolio of sustainable insect control options for agriculture pests and mosquitoes. He described them as non-GM, non-toxic and benign to other species, including pollinators and beneficial insects. His company, he said, would start with the codling moth, a major muncher of apples, and spotted wing Drosophila, another hard-to-control pest of soft fruit.

EXCLUSIVE: BigSIS pre-seed funding round

His technology, Slade revealed, has attracted precede investment from private angel investors and members of Cambridge Agritech, a UK investor syndicate. The new board will comprise three of these investors, plus Slade.

With the funding, the company will develop, test and commercialise a series of insect control solutions for farmers and mosquito control agencies. And enable BigSIS to establish a UK laboratory and team, and prepare rapidly for first test releases of sterile male codling moths in the second half of this year.

The decentralised, automated growing process envisioned by Slade contrasts sharply with large scale, centralised centers like the screwworm mass-rearing facility in southern Mexico — this center has been operated by the joint Mexico-United States Commission for the Eradication of the Screwworms since the 1970s, and is still largely defined by the nuclear radiation technology of that era.

For anyone wondering at this point if sending ever more invasive swarms of insects like the screwworm or the coddling moth is intuitive, it is worth keeping something in mind. The key part is that it works best on species where the real pests are the hungry kids: the larvae. The adult males are more abstemious on the food front; they do not live long, and are more focused on a frantic quest to breed or die. Effective use of sterile males requires good knowledge and data of the correct time to disperse them onto the dating scene. Where this technique might not work so well is with pests like locusts, where it is very much the adult population that are currently ravaging fields in East Africa in the largest locust plague for 70 years.

Don’t forget about pheromones

SIT has plenty of viable rivals in the area of disrupting mating patterns to reduce insect populations. One is the synthetic manufacture and wafting of pheromones, the naturally-occurring chemicals secreted by animals, and particularly prevalent in insects, that control mating and other behaviour. Reproduced in laboratories using biomimicry, these pheromones can be applied to crops thereby controlling invasive insects and replacing conventional, often toxic, synthetic pesticides.

In one sign of confidence in pheromones, ADM Capital Europe, the London-based private equity firm which runs the Cibus Fund, led a €60 million funding round for M2i Life Sciences last year, acquiring a minority stake in the European leader and one of the few global players in the pheromone market. M2i produces pheromones to replace chemical pesticides in agriculture, parks and gardens. These refined pheromones are known to biologically protect against the most common pests, for example, in specialised crops such as apple trees, vineyards, tomatoes, banana trees and in broad acre crops such as corn and cotton. M2i also manufactures specialist products for gardens, parks and forests, protecting box trees, palm trees and pine trees from invasive insects. The company currently sells more than 60 products across 25 countries.

Other players in the pheromone space are consolidating and growing. Late last year ISCA Global was formed through the merger of ISCA Technologies (US), ISCA Tecnologias (Brazil) and ATGC Biotech (India) to bring together 25 years of research and development into insect control products that are less harmful to the environment.

Outlining why he preferred SIT to pheromones, Slade described the latter as not as cost effective as his process. But there’s every chance both will continue to make a case for investment — and societal pressure will continue to play its part.

In 2019, the journal Biological Conservation published a study that swiftly caught and held the attention of global newsrooms. It was titled “Worldwide decline of the entofauna: A review of its drivers,” and its top-line findings were stark, suggesting 40% of all insect species are in decline, with many en route to extinction within decades. Habitat loss by conversion to intensive agriculture, the study claimed, “is the main driver.” Agro-chemical pollutants, invasive species and climate change were also considered “additional causes,” with insecticides accused of collateral damage of non-target species. The study’s recommendation: “A rethinking of current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically based practices, is urgently needed to slow or reverse current trends, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide,” the study contended: “In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments.”

By Richard Martyn-Hemphill