Prevention of EPTC—Induced Epicuticular Wax Aggregation on Corn (Zea mays) with R-25788

Scanning electron microscopy (SEM) showed that EPTC (S-ethyl dipropylthiocarbamate) caused an aggregation of the epicuticular wax layer of corn (Zea maysL.). R-25788 (2,2-dichloro-N,N-diallylacetamide) prevented this aggregation when applied in combination with EPTC. Neither EPTC, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], nor R-25788 changed the weight of chloroform extractable epicuticular wax on corn leaves. EPTC apparently does not block lipid synthesis in corn as it does in other plant species. Thus R-25788 does not protect corn from EPTC or metolachlor by overcoming such a block. EPTC did affect wax arrangement on the leaf surface and caused an increase in the cuticular transpiration of corn and predisposed corn to injury from subsequent postemergence applications of paraquat (1,1′-dimethyl-4,4′-bipyridinium ion). R-25788 protected corn against these deleterious effect.