Screening Of Fungicides For Controlling Wheat Scab And Preparation Of Suspension Emulsion

Wheat scab is one of the main wheat diseases in China,which has great influence on the yield and quality of wheat.In terms of pesticide control of wheat scab,the long-term use of the same drug leads to the increase of Fusarium graminearum which greatly increases the difficulty of control.Therefore,it is of great significance to develop efficient and environmentally friendly pesticide formulations for wheat scab.In this paper,single agent and compound agent were selected for the control of the above diseases,which provided the basis for the preparation of suspension emulsion.The processing method and formula selection of suspension emulsion were studied.The main results of this paper are as follows:Through the indoor toxicity test of 8 kinds of fungicides to F.graminearum,two kinds of fungicides,such as prothioconazole and benziothiazolinone were selected.the EC50 values against F.graminearum were 0.553 ?g/mL and 0.947 ?g/mL,respectively.The indoor virulence and synergistic coefficient of the bactericide prothioconazole and benziothiazolinone against F.graminearum were determined:when prothioconazole:benziothiazolinone=4:1,the synergetic coefficient was 1.696,greater than 1.5 showed synergistic effect.On the basis of the selected compound fungicide,20%prothioconazole·benziothiazolinone suspension emulsion was developed,including the screening of auxiliaries and the determination of product properties.The formulation of 20%prothioconazole·benziothiazolinone suspension emulsion was determined as follows:16%prothioconazole,6%Morwet-D425,0.3%xanthan gum,0.7%defoamer,6%ethylene glycol,4%benziothiazolinone,4%150#solvent oil,8%MOA-7,2%PEG600MO,water replenishment to 100%.The preparation of 20%prothioconazole·benziothiazolinone suspension emulsion of the above formula was carried out by using the preparation mixing method,and the influence of the processing technology on the stability of the product was preliminarily studied,the results show that the shear rate of 5000 r/min and the shear time of 20 min are the best conditions for the preparation of suspension emulsion..The indexes of the prepared suspension emulsion conform to the product standard of suspension emulsion.