Realationship between spray droplet spread and herbicide phytotoxicity

摘要

Experiments were conducted to deterine the relationship between spray droplet spread and hergicide phytotoxicity when secondary alchol etoxylate (SAEO) surfactants were used as spray adjuvants. Plant species evaluated were barley and green foxiail (grass species) and kochia and redroot pigween (boradleaf species). Herbicides evaluated were sethoxydim (Poast~( direct R )) and glyphosate (honcho~( direct R ) and Poundup~( direct R ). C_(11-15) SAEO surfactants evaluated had hydrophilic :lipophilic balance (HLB) values from 8 to 18. Spray droplet spread on adaxial leaf surface was greater with surfactants having lw (8 to 12.1) compared to high (15.4 to 18) HLOB values. Droplet spread appeared ralated to epicuticalr wax structure. Droplet spread was greater on microcrystalline epicuticular waxes (barley, green foxtail, and kochial) than on amorphous epicuticalar waxes (redroot pigweed). The presence of herbicide affected spray droplet spread on leaf surfaces. Phtotoxicity was greatest when Poast~( direct R ) and Roundup~( direct R ) were applied with surfactants having HLB values of 17.4 to 18. Efficacy of Honcho~( direct R ) and Roundup~( direct R ) was negatively correlated with droplet spread, while the efficacy of Poast~( direct R ) did not correlate with droplet spread.