Furan tebufenozide is a newly developed insect growth regulator and has been applied as a pesticide in agriculture in China.Its degradation under both laboratory and field conditions was investigated,and the degradation kinetics was fitted by simple first order kinetics (SFO) model and first order double exponential (FOD) model.Laboratory studies were conducted with or without light in five simulated media (sterilized deionized water,river water,soil solution,sterilized soil and natural soil).No dissipations of furan tebufenozide were observed in sterilized aqueous and soil media under light prevented conditions,whereas degradation occurred under all the other conditions in the laboratory.Derived from SFO and FOD models,DT50 in the dark and light laboratory conditions was in the range of 39.7-82.5 and 1.1-8.0 days,respectively.These results indicated that microbes and light were the main factors for the degradation of the pesticide in the laboratory.During field trials,derived from the SFO model,DT50 and DT90 were 30.3 and 100.5 days,while derived from the FOD model,DT50 and DT90 were 28.9 and 274.9 days,respectively.Compared with laboratory experiments,field trials were influenced by multiple factors.Therefore,the SFO model could not fit experimental data as well as the FOD model did in field trials.
GUO Cong,LI DaHui,CHEN JinHui,GUO BaoYuan,WANG HuiLi & LI JianZhong Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China
Strobilurins have become one of the most important classes of agricultural fungicides. To discover new strobilurin derivatives with high activity against resistant pathogens, a series of novel fl-methoxyacrylate analogues were designed and synthesized by integrating substituted pyrimidine with a strobilurin pharmacophore. The compounds were confirmed and characterized by infrared, 1H nuclear magnetic resonance, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds 1 exhibited potent antifungal activity against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at the concentration of 50 μg/mL. Exhilaratingly, compound 1 a （R= methyl） showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.
