Pesticide Effects on the Plant Cuticle: I. Response of Brassica oleracea L. to EPTC as Indexed by Epicuticular Wax Production1

Production of epicuticular wax by expanding leaves of cabbage ( Brassica oleracea L. var. capitata cv. Market Prize) was inhibited by S-ethyl dipropylthiocarbamate (EPTC) and trichloroacetic acid (TCA). Increasing the concentration of EPTC (0, 0.28, 0.56, 1.12 and 2.24 kg/ha) resulted in greater inhibition of epicuticular wax production. Both soil and foliar application of EPTC were effective. All leaves not fully expanded at time of application were affected, and no regeneration of epicuticular wax was evident after full leaf expansion. The difference between the amount of wax produced by the control and EPTC-treated plants gradually declined on those leaves which developed after EPTC application. This reduction was accompanied by an absence of wax bloom and a reduction of surface wax fine-structure.