Influence of particle size and type of formulation on phytotoxicity and persistence of atrazine

摘要

Summary:The initial and residual activities of wettable powder formulations of atrazine comprising different particle sizes were investigated in field and glasshouse experiments. A flowable formulation was also compared with these. Oats were used as the test species for the glasshouse studies while in field trials effects on control of broadleaf weeds in maize were studied. No marked differences were noted in the activity of wettable powders of different particle sizes in the glasshouse as pre‐emergence applications. As a post‐emergence treatment the fine particle size was more phytotoxic than the coarse material, especially when a wetting agent was added to the spray solution. In the field trials, no appreciable differences in weed control or crop tolerance could be established regardless of the time or rate of application. The flowable formulation was less active than the wettable powders in some glasshouse experiments but no such trend was apparent in field trials. Bioassays showed that the residual activity of the flowable formulation was lower than wettable powder formulations in both glasshouse and field studies but no consistent differences were noted in the persistence of the three forms of wettable powd