Studies On Biological And Parasitized Characteristics Of Ampelomyces Quisqualis

Ampelomyces quisqualis is the hyperparasite of powdery mildew. The rate of distributtion of A. quisqualis is very low in natural filed, but it has no selectivity to parasitize the genus and species of powdery mildew and it is also resistant to a number of chemical fungicides. In recent years, there have been a lot of literatures reported on A. quisqualis in the world, but very few in China. Particularly, the AQ-10, a kind of new biological fungicide was developed and widely applied in foreign country to control powdery mildew of vegetables and flowers in the greenhouse. Therefore, in order to understand the knowledge of biology and hyperparasitic mechanism of A. quisqualis, this paper deal with the biological, parasitic characteristic of A. quisqualis and the interaction between the A. quisqualis and powdery mildew. The results are as follows:1. Biological characteristics of A. quisqualis(AQ)were studied. The result showed that A. quisqualis could grow at temperature of 10～30℃and pH value of 5～10,the optimal temperature and pH value for its growth and sporulation were at 20℃and 7 respectively. The Glucose, lactose and peptone were optimal C and N sources for its growth, lactose and beef extract were adapted to its sporulation. Light could effectively stimulate AQ growth and sporalation. Czapek medium added with lactose as C sources and beef extract as N sources were optimal to AQ sporulation.2. Parasitizing and controlling effects of different isolates of A. quisqualis on powdery mildews were various. It had high rate of parasitic effect and spore germination while spore concentration of A. quisqualis adjusted with 10⁶ml^-1 was applied to inoculate the powdery mildew. Among isolates of A. quisqualis, AQ-40, AQ9, AQ117 were better to against cucumber powdery mildew in greenhouse while AQGA-22, AQB15-20 and AQ-13 were better to against apple powdery mildew in the field. It indicated that those isolates of A. quisqualis would have highly biocontrol potential against powdery mildew of cucumber and apple. 3. Conidia of powdery mildew were applied on the surface of cellofen and also were inoculated on the fresh colonies of cucumber powdery mildew. After a few days of...