Abstract:

A species of entomogenous fungus was isolated from dead insect bodies of citrus aphid in Nanping city, Fujian Province. The species was identified as Fusarium lateritium Nees. of the genus Fusarium. The causal organism grew vigorously on PDA medium. Mycelia of the fungus grew at temperature range 10～35℃, and with an optimum at 20～26℃. The conidia was produced after incubation of 3 days at 25℃.The optimum temperature for conidial germination was between 20～25℃. The high relative humidity (96%～100%) was necessary for the germination of conidia. Bioassay results indicated that the fungus showed higher virulent to the larvae of citrus aphid. The LC₅₀ was 2.71×10⁷ spores·L^-1, and the LT₅₀2.21～6.34 days for the concentration of 10×10¹¹～10×10⁷ spores·L^-1.The spore suspension of F.lateritium was applied to control test in the field against citrus aphid, and the mortality was 91.80%.

Key words: Aphis citricidus, Fusarium lateritium, Conidial germination, Toxicity, Control test