Evaluation of the effects of scorching caused by the directed application of a paraquat-containing herbicide mixture to the base of maize plants at various ages

摘要

The effect of herbicides which scorched the lower leaves of maize was compared in three seasons. The first season was relatively dry whilst the other two were wetter seasons. A mixture of cyanazine + atrazine + paraquat + a wetting agent was applied as a directed spray at the base of maize plants at weekly intervals from four till eight weeksafterplanting. These treatments were compared with weedfree, unsprayed maize. Plant heights ranged from 0,1#x2013;1,0 m at spraying. Many of the younger maize plants were severely scorched and some were killed by the earliest treatment (4 weeks) and grain production was lower but only significantly reduced in one season out of three. Maize which was sprayed at later stages lost some lower leaves but this did not affect grain production or did not consistently affect other maize attributes.