In Vitro Method For Producting Milky Spore

Scarabaeidae is one kind of the pests which seriously affect the agriculture, forest, and farming in almost all the countries over the world. It is a problem as an adult beetle because it feeds on a wide range of plants, eating out the leaf tissues between the leaf veins, and it accumulates on ripening fruit causing substantial damage. It is also a problem in the larval stage because the grubs destroy the plant roots and lead to the plants wilt. Therefore, how to control the Scarabaeidae effectively is very important in the domain of pest control.Bacillus popilliae are specialised pathogens of the scarabaeid beetles, which cause milky disease in said Scarabaeide. The pesticides comprising an amount of spores of Bacillus popilliae can control the Scarabeaide safely and effectively. However, this bacterium has extremely fastidious requirements for growth and spore- forming, and it is very hard to get spores in vitro. This dissertation disclosed a method for producing Bacillus popilliae spores in vitro in liquid media containing starch, glucide, yeast extract, K.sub.2 HPO.sub.4, and CaCO.sub.3. According to the research of the factors that affect the bacteria's growth and spore-forming, we found the best method for producing the spores: Aseptically inoculated with 1% inoculum a sterilized medium comprising glucose and having a pH about 7.6; incubated the culture at 30 degree under continuous mechanical maxing at 200rpm for 16h; adjusted the pH to 8.0; added manganese sulfate and adsorbent resins as sporulation adjuvants; went on incubating the culture at 30 degree for 24h; and finally harvested the spores by lyophilization. By the present invention, sporulation rates of more than 70% are achieved.This research is very meaningful. It provides a method for obtaining large quantities of milky disease spores in vitro, which is the foundation of large scale production. Besides that, this research can promote the development of biological pesticides which can take place of the chemical pesticides in the Scarabaeidae control.