Squash trichome traits are associated with Bemisia tabaci abundance and treatment efficacy across cultivars

Authors: MBATA, GEORGE - Fort Valley State University; WARSI, SANOWER - Fort Valley State University; PERIER, JERMAINE - Mississippi State University; TOEWS, MICHAEL - University Of Georgia; Shapiro Ilan, David; Simmons, Alvin

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2026
Publication Date: 9/9/2026
Citation: Mbata, G., Warsi, S., Perier, J., Toews, M.D., Shapiro Ilan, D.I., Simmons, A.M. 2026. Squash trichome traits are associated with Bemisia tabaci abundance and treatment efficacy across cultivars. Journal of Pest Science. https://doi.org/10.1007/s10340-026-02092-4.
DOI: https://doi.org/10.1007/s10340-026-02092-4

Interpretive Summary: Certain fungi are useful as biological control agents because they kill insect pests; this includes the major crop pest swetpotato whitefly. A study was done to determine if there were any differences in impacts on populations of whiteflies based on the type and number of hairs on leaves of certain squash cultivars when the plants were treated with different types of insecticides, including fungi-based insecticides. Squash cultivars with leaves harboring few and short hairs had more whiteflies, and cyantraniliprole-based insecticides were less effective on these cultivars. However imidacloprid-based insecticides resulted in the most whitefly mortality, and the reduction in whitefly population was independent of the different leaf hairs on the different cultivars. Results from this study are useful for researchers in designing pest management strategies that reduce the potential of the whiteflies developing resistance to insecticides.

Technical Abstract: Two entomopathogenic fungal strains, Beauveria bassiana (Bals. -Criv.) Vuill. GHA and Cordyceps javanica (Bally) Kepler, B. Shrestha & Spatafora wfGA17 (Hypocreales: Cordycipitaceae), are biological control agents of the sweetpotato whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), a major pest causing substantial yield losses in squash (Cucurbita pepo L.). Previous research has shown that the efficacy of these entomopathogenic fungi (EPF) and chemical insecticides varies across squash cultivars. This study examined interactions among trichome traits of squash cultivars, B. tabaci populations, and treatments, including Entomopathogenic Fungus (EPFs), insecticides, and their combinations, at 7 days post-treatment to identify cultivar-specific patterns. The results showed that trichome density, length, and diameter varied among squash cultivars, with B. tabaci nymph abundance decreasing as non-glandular trichome density increased in a cultivar-dependent manner. Trichome density was negatively associated with B. tabaci nymph abundance. Early Summer, Fortune, Respect, and Gentry cultivars aligned with higher trichome density and lower nymph abundance, while Green Eclipse, Golden Glory, Lioness, and Gray Summer had lower trichome densities, and consistently associated with higher nymph densities. Trichome density contributed substantially to variation in nymph mortality with cyantraniliprole-based applications, whereas imidacloprid-based treatments were dominated by mortality effects largely independent of trichome traits. Overall, imidacloprid based treatments resulted in the highest nymph mortality across cultivars. Fortune, Green Eclipse, Golden Glory, Respect, and Lioness cultivars responded similarly, regardless of treatment type (EPF species alone, chemical insecticide alone, and EPF-insecticide combinations). In contrast, Early Summer, Gray Summer, and Gentry changed their responses depending on the treatment, especially under fungal and insecticide–fungal combinations. This study provides a model for understanding plant–insect–fungus interactions and offers tools to design pest management strategies that mitigate pesticide resistance.