Instead of chemicals, an army of ants may march right in. Though most people view the small insects as little more than a nuisance, colonies of them are being deployed in orchards across a handful of countries to stave off the spread of crippling infestation and disease.

In a body of recently published and forthcoming research, Jensen examined the antimicrobial effects of wood ants, a European field ant known for building dome-shaped nests in fields and open woodlands, and weaver ants, which live in ball-shaped nests within tropical tree canopies across Asia, Africa, and Australia.

Past studies have found that for crops from cocoa to citrus, ants could replace insecticides in a multitude of climates and locations, reducing incidences of pear scab in pear trees, coffee leaf rust in coffee shrubs, and leaf fungal attacks in oak seedlings. Weaver ant nests used as an alternative pesticide in mango, cashew, and citrus trees have all been shown to lower pest damage and produce yields on par with several chemical pesticide treatments. For more than a millennia, the species was embraced as a natural insecticide in countries like China but never quite made its way into the agricultural mainstream in North America or Europe.