Kaolin particle films deter oviposition,impair early development of key soybean herbivore guilds,and enhance plant physiological resilience

Authors: DEBNATH, RAHUL - University Of Arkansas; George, Justin; KARIYAT, RUPESH - University Of Arkansas; Little, Nathan; Portilla, Maribel; Reddy, Gadi

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2026
Publication Date: 7/1/2026
Citation: Debnath, R., George, J., Kariyat, R., Little, N., Portilla, M., Reddy, G.V. 2026. Kaolin particle films deter oviposition,impair early development of key soybean herbivore guilds,and enhance plant physiological resilience. Pest Management Science. https://doi.org/10.1002/ps.71053.
DOI: https://doi.org/10.1002/ps.71053

Interpretive Summary: Kaolin-based particle films, made from natural clay, offer farmers a practical, eco-friendly way to protect crops. These films coat plant surfaces, reducing insect damage, disease, and heat stress without relying on synthetic chemicals. While kaolin has been used against many pests, its real-world effectiveness on major row crops has been unclear—until now. Our research shows kaolin works in two key ways: it creates a physical barrier and discourages insects from laying eggs. In soybeans, kaolin reduced attacks from pests like soybean looper and southern green stink bug. Lab and field studies found that treated plants had fewer pests, healthier growth, and improved resilience. Field trials showed kaolin performed much like an insecticide—without chemical inputs. For farmers, this means lower pest pressure early in the season, fewer insecticide applications, and reduced production costs. Kaolin is safe for pollinators and beneficial insects, supports soil health, and works well with other crop treatments. It is cost-effective, easy to apply, and helps farmers maintain long-term land productivity. By reducing reliance on synthetic insecticides and improving crop resilience, this research supports USDA’s mission to strengthen U.S. agriculture through sustainability, profitability, and resilience for farmers and rural communities. Kaolin-based films give growers a tool to protect yields, reduce input costs, and meet consumer demand for environmentally responsible farming.

Technical Abstract: Female insects exhibit oviposition preferences that maximize the survival and development of their progeny. Although kaolin-based particle films are reported as physical repellents against herbivory, a significant research gap exists in their impact on herbivore feeding behavior and modulation of physio-chemical dynamics in row crop systems. We investigated how foliar application of kaolin impacts soybean defenses against two generalist and highly destructive insect pests, soybean looper (SBL, Chrysodeixis includens) and southern green stink bug (SGSB, Nezara viridula). Our results show that gravid females exhibited significant avoidance of kaolin and insecticide-treated plants during the oviposition choice assays. Evidence from behavioral choice assays using larvae/nymphs indicated that kaolin strongly enhances soybean defenses against herbivore attack. Significant reduction in the survival of immature stages on treated plants indicated that kaolin adversely affects early insect development. Analyses of plant physiological and biochemical traits showed that kaolin particles not only facilitate as physical barriers, but also improve plant physio-chemical resilience. Moreover, field applications further showed that insect pest abundance was significantly lower on kaolin treated plants, compared to untreated control plants, mimicking insecticidal effects. Together, these findings highlight kaolin’s dual role as a physical barrier and as an ovipositional deterrent, reinforcing its potential as a sustainable, non-chemical strategy for integrated pest management aimed at restricting early pest establishment and mitigating overall pest pressure under field conditions.