Organic management promotes natural pest control through altered plant resistance to insects

Organic farming is known to increase natural pest control that helps organic farmers overcome reliance on chemical pest management. While the common perception is that natural pest control is largely boosted by practices that increase natural enemies to pests, a recent study in Nature Plants explored a less common theory. This found that organic management also boosts the natural defenses of plants to prevent pest damage even when pests are abundant. Because organic farmers cannot use the same chemical pest control tools as conventional, they use other creative strategies to reduce pests such as planting non-crop vegetation that supports natural enemies that attack pests, rotating crops so that pests don’t accumulate in the same place year after year, and managing soil fertility with biological soil amendments instead of synthetic nitrogen. Plants with less nitrogen have been shown to be less attractive to pests. This study made an interesting discovery. While pests were present in both systems, they did not linger on the organic plants and it was not because of nutrient differences. The organic plants and conventional plants had the same amount of nitrogen. Instead, the researchers found that organic management increased the abundance and diversity of beneficial bacteria and fungi in the soil which, in turn, stimulated the production of phytohormones that deterred pests from settling on the plants. This research shows an additional advantage to improving soil health and that healthier soils can also promote long-term pest management for organic farmers.


Banner Photo Credit: Sara Codair;