Global crop losses due to pests, weeds, and disease reach alarming levels each year — and the trend is worsening with globalization and the rapid movement of herbal products. New outbreaks and rising resistance to phytosanitary products challenge farmers worldwide. In response, researchers are pursuing practical solutions. A recent study found that intercropping, the practice of growing mixtures of crops, can effectively curb pest pressures.
The agricultural sector faces a slew of pressures today. Climate change is driving more extreme temperatures, while soil erosion and other risks threaten long-term viability. These factors elevate the likelihood of pest outbreaks, making effective control more critical than ever.
A new study from the University of Florida, published in the Journal of Applied Ecology, confirms that intercropping can be a powerful pest management strategy across the globe.
The analysis drew on 44 field studies conducted across six continents and examined four crops — cabbage, squash, cotton, and onion — both in monoculture and in mixtures with closely related species.
Across these studies, researchers recorded 272 estimates of herbivorous insect abundance on the plants, covering 35 different insect species. This represents one of the most comprehensive assessments of intercropping effectiveness to date.
Pest-related losses continue to hit the agricultural economy hard. Yet intercropping also offers a path to reduce these losses while supporting ecological balance.
“Crop diversification presents a promising approach to meet growing global food demand while preserving ecosystem services, because it lowers pest abundance overall,” the study notes. In particular, dual-culture systems showed substantial reductions in insect populations within the focal crops.
The three sisters
“Intercropping has proven effective against many pests, though results vary with pest type and feeding preferences,” explains Philip Hahn, an assistant professor in the Department of Entomology and Nematology at UF/IFAS, who led the study. “Crop type matters too; cabbages and pumpkins tend to show stronger resistance, while onions and cotton may be less protected.”
Some practical defragmentation methods naturally complement intercrops. Non-commercial crops placed at field margins can deter pests from reaching the cash crop. Likewise, complementary crops sown within the field can hinder pest establishment. A well-known combination is the Three Sisters — corn, squash, and beans — which helps keep pests from settling on main crops.
The study also found that mixed planting schemes like the Three Sisters often make it harder for pests to locate their preferred host plants and can be more effective than border plantings alone.
“In the studies reviewed, intercropping emerged as the most effective general pest management method,” Hahn notes. “Pests that feed on multiple crops respond well, whereas highly specialized pests may be less affected by neighboring companion plants.”
The explanation lies in coevolution: specialized pests often adapt to a single host, so the presence of nearby allies can disrupt their locating mechanisms and feeding behavior.
Better results in tropical regions
Researchers have long explored intercropping’s value, tapping into a wealth of published data. The UF/IFAS team integrated earlier analyses with newer research to provide a robust assessment of the conditions that maximize the benefits of mixed cropping.
While variability exists across studies, a geographical pattern becomes apparent, though modest. The analysis indicates stronger pest suppression benefits at lower latitudes, meaning tropical systems generally show greater reductions in pest pressure than northern temperate ones.
As with any model, there are caveats. Tropical regions host a greater diversity of insect species year-round, yet the expectation that this would produce an even stronger effect did not always materialize. The findings suggest that neighbor plant choices may be crucial to success in intercropping systems.
These insights form a foundation for future work, highlighting which companion herbs yield the strongest pest reductions and which pairings may be less effective. The takeaway for producers, especially those practicing organic methods, is clear: mixed cropping can be a highly effective tool for managing pests while supporting sustainable farming practices.
Further research will refine expectations for different crops and climates, but the current results already provide practical guidance for designing effective companion plantings and optimizing field layouts for pest control.
Note: The study is available through Wiley Online Library in the Journal of Applied Ecology, and ongoing work continues to explore the nuanced interactions among crop types, pests, and geographic contexts.
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