| Popis: |
【Objective】This study aimed to evaluate the biocontrol potential of an entomogenous fungus strain isolated from Phenacoccus solenoposis, for providing the basis of its development as a biocontrol agent.【Method】The strain was isolated and purified from the diseased P.solenoposis using tissue isolation method. Based on the cultural traits, morphological traits and phylogenetic tree analysis, its taxonomic ststus was clarified. The infection mode of strain on P.solenoposis was explored by scanning electron microscope, which clarified its ability to infect P.solenoposis. The pathogenicity of the strain to P.solenoposis was measured by leaf dipping and insect dipping method.【Result】A strain FE-1 was isolated and purified from the diseased P.solenoposis, the morphological traits results showed that the colony diameter of strain FE-1 ranged from 50 to 60 mm at 5 days on PDA medium, and the colony was orange-white in front. The conidia morphology had two types, which small type was long column shape and large spore was sickle shape. The strain FE-1 was identified as Fusarium equiseti based on cultural traits, morphological traits and phglogenetic tree analysis. The strain FE-1 infected into the insect body cavity of P.solenoposis mainly by conidia germination forming germ tubes at the epidermis for growing horizontally, and the formation of expanded appressorium at the specific contact epidermis, which clarified its ability to infect P.solenoposis. The results of indoor toxicity measuremerts showed that the pathogenicity of strain FE-1 against female adults of P.solenoposis was gradually increased with the concentration of conidial suspension. At the spore concentration of 1×108 CFU / mL, LT50 was 3.32 days, while at 7 days after inoculation, the adjusted mortality of P.solenoposis female adults was 87.50±1.79%, LC50 was 1.8×105 CFU /mL.【Conclusion】A strain FE-1 isolated and purified from the diseased P.solenoposis can form expanded appressorium at the specific contact epidermis for infection, which clarifies its ability to infect P.solenoposis. Meanwhile, the strain FE-1 is highly pathogenic against P.solenoposis, which has great potential for biocontrol and provide original material for the biocontrol research of P.solenoposis. |
