Abstract: Primary biodegradability of the new blend pesticide adjuvants,rosin-based surfactant adjuvants No.1 and No.2,as well as that of the conventional pesticide adjuvants,including polyoxyethylene nonylphenol ether,rosin acid polyethylene glycol ester,and polyoxyethylene lauryl alcohol ether was investigated in laboratory tests of 8 d.The results indicated that primary biodegradability of rosin-based surfactant adjuvants No.1 is 79.1%,that of No.2 is 82.4%,that of rosin acid polyethylene glycol ester is 84.2%,that of polyoxyethylene nonylphenol ether is 91.1%,and that of polyoxyethylene lauryl alcohol ether is higher than 99%.It is obvious that the chemical structure of the new blend pesticide adjuvants is more complex and with lower primary biodegradability as comparing with that of the conventional pesticide adjuvants.

Key words: surfactant, pesticide adjuvants, primary biodegradability