Concentrations of phytohormones (ng/g fresh weight) in cotton, corn, and tomato plants exposed to neonicotinoid insecticide.

U: Untreated, N: Neonicotinoid insecticides thiamethoxam (cotton), clothianidin (corn), and imidacloprid (tomato). Four-week old plants were used in the experiment. Tomato plants were treated with soil applications of imidacloprid seven days prior to the experiment. Means were compared using ANOVA (F statistic) or non-parametric Kruskal-Wallis test (X2 statistic).