Abstract
We dealt with the effects of surfactants on herbicidal activity and the following results were obtained.
The nonyl phenol ethylene oxide surfactant (No.4) and the trimethyl stearyl ammonium salt surfactant (No.17) highly enhanced the activity of Asulam against annual bluegrass (Poa annua) .The HLB (Hydrophilic Lipophilic Balance) value of nonionic surfactants giving a maximum effect on Asulam was about 12.
Surfactants apparently enhanced the activity of Bialaphos. The number of ethylene oxide and the HLB values of nonionic surfactants giving higher effect on Bialaphos were in the range 8-12 and 12-14 respectively.
In general, the phytotoxicities of the four nonselective foliar-applied herbicides, Glyphosate, Bialaphos, Alloxidim and NaOCN, were increased by the addition of surfactants. Particularly, the highest joint action was observed with NaOCN and the degree of the joint action decreased in the order of Glyphosate> Bialaphos> Alloxydim.
The concentration of surfactants for a maximum enhancement of the herbicidal activities was in the range 0.1-0.3%.
