Want To Lessen Pests in Your Farm Fields? Intercropping Might Be the Answer
Intercropping – the practice of planting mixtures of crops – can be an effective pest management tool worldwide, a new University of Florida study demonstrates. The analysis compiled results from 44 field studies across six continents and focused on four crop types – cabbage, squash, cotton, and onion – planted on their own and mixed with a companion plant species. In these studies, scientists recorded 272 total occurrences of 35 different species of plant-eating insects on crops.
“Overall, intercropping proved to be very effective against pests, but it did vary based on the pest and their feed preferences,” says Philip Hahn, Assistant Professor in the UF/IFAS Entomology and Nematology Department, who led the study. “It also depended on crop type, with cabbage and squashes showing the strongest resistance, while resistance was less strong for onions and cotton.”
There are a few common methods of intercropping, according to researchers. Sometimes non-cash crops are arranged in borders surrounding the field to repel or intercept pests before they damage the cash crop. Companion plants can also be planted within the field to disrupt pests from locating the main crops. A common combination is known as the Three Sisters: corn, squash, and beans. Another of this study’s findings was that interspersed planting schemes, like the “Three Sisters,” make it more difficult for the pests to locate their preferred host plant and were more effective than border plantings.
“In the studies we examined, we found intercropping was more effective for generalist pests that feed on a variety of crops,” Hahn adds. “Specialist pests that target one type of crop were less affected.”
While variability proved to be a common thread across studies, Hahn notes that a geographical pattern arose, however weakly.
“We did find a stronger benefit for pest suppression at lower latitudes – so, in tropical systems versus northern temperate systems,” he confirms. “There are lots of reasons we could have found that pattern, of course; the tropics are places where there tend to be more species of insects year-round. It was surprising that the pattern was not as strong as I would have expected.”
This analysis will likely inform future investigations, Hahn concludes.
The study, funded by the National Science Foundation, is available at doi.org.
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