Photolysis And Residue Decline Study In Soil And Wheat Root Of Two Formulations Abamectin

Avermectin (abamectin) is a kind of insecticidal, acaricidal, nematicidal activity of sixteen macrocyclic lactones compound. It belongs to the family of avermectins which are produced by the actinomycete Streptomyces avemitilis.Abamectin consists of≥80%of avermectin B1a and≤20%of avermectin B1b. its main component is B1a. Avermectin to Pieris rapae, Spider mite and a variety of mites have good killing effect, and has the advantages of high efficiency, broad spectrum, reducing environmental pollution characteristics. Avermectins was the high efficiency biogenic pesticides and largely applied for controlling agricultural pests. The method for determination of avermectin residues and degradation dynamics was reported lot, but the different formulations of avermectins in varied environmental conditions was not reported. The residual dynamics of abamectin in1.8%(w/w) emulsifiable concentrate and2%(w/w) microcapsule suspension under UV radiation, in soil and seed coat of wheat were studied in this papers. The results showed that:1. the declination rate of abamectin prepared with two different formulations under three environments followed the first-order kinetics and the early determination rate are high compared with low late.2.Compared with emulsifiable concentrate, the residue declination rate of abamectin encapsulated in microcapsule was delayed under UV light. The microcapsule surface have an effect on composition segregation and play a role in protection; Effective component of EC is directly contact with the ultraviolet rays, the abamectin molecules in the same time to absorb more photons, led to its chemical structure changes.3.The half-lives of abamection with emulsifiable concentrate and microcapsule at the dosage of5mg/kg and20mg/kg were88.86d,157.52d and22.14d,82.51d respectively in soil. In the seed coat of wheat, the residue of abamectin prepared with microcapsule was higher than that with emulsifiable concentrate, so the former could have longer persistence in field.