Brassinosteroids (BRs) are steroid hormones that regulate plant growth, development, and stress resistance. In this study, we evaluated the effect of agrochemicals on dark-induced hypocotyl elongation, which is regulated by BRs, to identify novel chemicals BR action. We found juvenile hormone agonist fenoxycarb inhibited elongation in Arabidopsis. Treatment with same class agonist, pyriproxyfen...