Abstract: Bacillus velezensis has great potential in the development of microbial pesticides. The research and development of its wettable powder and the optimization of its production process are one of the measures to promote its industrialization and commercialization. In addition, it is of great significance to promote the green development of agriculture and realize green prevention and control. B.velezensis SH-1471 was used as the research object. Single factor test was used to select the carrier and additive that had the least effect on its activity and its compound proportion. The control effect of B.Velesiensis SH-1471 WP on tomato Fusarium wilt was determined in a pot experiment. The formulation and ratio of B.velezensis SH-1471 WP were established as follows:kaolin as carrier parent powder 87%, sodium lignosulfonate 2%, NNO 8%, xanthan gum 2%, ascorbic acid (VC) 1%; The viable count of the preparation was 2.5×10¹⁰ CFU/g, fineness 97%, wetting time 12 s, suspension rate 88.6%, drying reduction 1%, pH 7.1, and impurity rate 0. All the indicators were in line with the national standards. The continuous storage experiments showed that the survival rate of spores reached 87.65% at 4℃ for 180 d and 82.45% at 25℃. Laboratory experiments showed that it had a good control effect and could significantly reduce the incidence of tomato Fusarium wilt, with a control effect of 93.7%. B.Velesiensis SH-1471 WP has the characteristics of good stability and high control efficiency, and has a good application prospect in the biological control of crop diseases.

Key words: Bacillus velezensis, wettable powder, tomato Fusarium wilt, control effect