Screening Of Microbial Strain For Biological Control Of Arceuthobium Sichuanense

The dwarf mistletoe (Arceuthobium sichuanense) is a perennial semiparasitic seed plant,belong to the Viscaceae Arceuthobium. Arceuthobium sichuanense mainly infects Picea crassifolia,Picea wilsonii and Pinus tabulaeformis through its internal parasitic systems for obtaining water and nutrients. The infected branches and trunks usually had abnormal swelling and formed the broom like branches. When the host is seriously infected, it will die. The purpose of this paper is to provide sources of strains for taking biological methods to control Arceuthobium sichuanense. By separation of tissue, hyperparasite was detached from stem and berries of Arceuthobium sichuanense. Because the previous studies showed that Colletotrichum gloeosporioides as biocontrol agents to control Arceuthobium sichuanense has good effect, we choose the Colletotrichum gloeosporioides strains. Colletotrichum gloeosporioides is the main pathogen of poplar anthrax. In order to verify the pathogenicity of the strains,the in vitro inoculation test was carried out. The selected strains were identified by morphological and molecular biological methods. Because the indoor screening of the strains had pathogenicity to Arceuthobium sichuanense, in the in vivo vaccination to consider whether the harm to the host. The safety of host was evaluated preliminarily by using the method of in vitro inoculation. The results were as follows:The incidence of Arceuthobium sichuanense collected from 3 compartment Menyuan County of Qinghai Province in Xianmi Forest Farm. A total of 95 samples were collected. The dwarf mistletoe symptoms can be roughly divided into the following categories:discoloration, necrosis, decay, wilting. The incidence of Arceuthobium sichuanense collected from the 1 compartment Dege County of Sichuan Province, Menza Ling Temple. A total of 5 samples were collected. The symptoms of Arceuthobium sichuanense was mainly necrosis.66 strains were isolated by tissue isolation method.The pathogenicity of 66 strains and 2 strains of Colletotrichum gloeosporioides was investigated via in vitro inoculation test by disk-wound and spore-suspension inoculation. The results showed that the 4 strains were pathogenic. They were Fusarium solani B2-2,B20-2 and Colletotrichum gloeosporioides M1-6,CFCC80308,respectively. Control don’t come on, not pathogens were isolated.The safety of Picea crassifolia was evaluated preliminarily by using the method of spore-suspension in vitro inoculation. The results showed that the strains were safe to the host,no pathogenicity. It can be used as biological control Arceuthobium sichuanense.The indoor screening of the 4 strains were inoculated in dwarf mistletoe plant. Results showed that the CFCC80308 has pathogenicity. Through the spore suspension inoculation, the incidence rate was 8.4%. The remaining 3 strains inoculated in the dwarf mistletoe is no disease symptoms.