Preparation Of 20% Fluazinam·Pyraclostrobin Suspension Concentrate And Its Control Effect On Anthracnose Of Pepper

Anthracnose of pepper is a serious disease in China that occurs more times and does more harm.Due to the influence of drug resistance,the control effect of single dose of common fungicides on disease is declining year by year.The use of compound fungicides can effectively avoid the occurrence of this situation.Fluazinam is dinitroaniline fungicide,and it has strong permeability,good protection and high stability.Pyraclostrobin is a kind of methoxyacrylates fungicide with high efficiency,broad spectrum,environmental compatibility and safety.In this study,fluazinam and pyraclostrobin were selected as the complex suspension agent.The aim is to develop a pesticide preparation with high efficiency,rapid effect,low risk of drug resistance,both protective and therapeutic effects,and safe for crops and environment.In addition for the chemical control of pepper anthracnose to provide a new choice of agents.This experiment mainly studied the following aspects:1.The optimum combination ratio of fluazinam and pyraclostrobin against anthracnose of pepper was selected.The toxicity of fluazinam and pyraclostrobin to Colletotrichum gloeosporioides and Colletotrichum capsici were determined.The EC₅₀values of fluazinam against Colletotrichum gloeosporioides and Colletotrichum capsici were 0.099μg/m L and0.234μg/m L.The EC₅₀values of pyraclostrobin against Colletotrichum gloeosporioides and Colletotrichum capsici were 1.179μg/m L and 2.957μg/m L.After preliminary screening tests,it was determined that the toxicity ratios of fluazinam and pyraclostrobin to Colletotrichum gloeosporioides were 1.67 and 1.64 when EC₅₀were 80%:20%and90%:10%.And the toxicity ratios of fluazinam and pyraclostrobin to Colletotrichum capsici were 1.60 and 1.58 at the same EC₅₀ratio.The combined toxicity test showed that when the mass ratio of fluazinam to pyraclostrobin was 3.25:6.75,the synergistic coefficient to Colletotrichum gloeosporioides was 1.76.When the mass ratio of fluazinam to pyraclostrobin was 3.75:6.25,the synergism coefficient against Colletotrichum capsici was1.88.Finally,the mass ratio of fluazinam to pyraclostrobin was determined to be 7:13.2.The selections of wetting and dispersing agents,thickening agents,antifreezing agents and defoaming agents were completed in order.We screened the types and dosage formulations of pesticide additives.Finally,the formulation of 20%fluazinam·pyraclostrobin suspension concentrate was determined as follows:7%fluazinam,13%pyraclostrobin,3%SC,2%T-2700,2%500LQ,0.28%xanthan gum,1%magnesium aluminum silicate,4%ethylene glycol,0.4%AF1501,0.2%kathon,1.2%citric acid,and water replenishment to 100%.3.The quality of 20%fluazinam·pyraclostrobin suspension concentrate was tested,and the results showed that the mass fraction of the active ingredient,suspension rate,viscosity,p H value,tipping property,lasting foaming property,particle size and other indicators were qualified.Heat storage stability and low temperature stability meet the standard.4.We did field tests about fungicides,the data showed that the control effects of 20%fluazinam·pyraclostrobin suspension concentrate were 76.91%,80.93%and 82.65%at the dosage of 40 g/667m²,50 g/667m²and 60 g/667m².The control effects of 500 g/L fluazinam suspension concentrate 30 g/667m²and 25%pyraclostrobin suspension concentrate 35g/667m²were 74.51%and 70.68%.The control effect of 20%fluazinam·pyraclostrobin suspension concentrate on pepper anthracnose was significantly higher than that of two control fungicides.The compound fungicide is safe for capsicum at recommended doses,and it has good control effect and the value of application.