Identification of Ice-nucleating Active Fungus Isolated from the Gut of the Rice Stem Borer, Chilo suppressalis Walker(Lepidoptera: Pyralidae) and a Search for Ice-nucleating Active Fusarium Species.

Abstract

Ice-nucleating active fungus isolated from the gut of larvae of the rice stem borer, Chilo suppressalis Walker was identified as Fusarium moniliforme Sheldon var. subglutinans Wollenweber et Reinking. Ice-nucleating activity (INA) around -5 degrees C was detected in the mycelial suspension and cell-free culture medium of the fungus. INA was also detected in tow strains of F. moniliforme, two of F. avenaceum and one of F. tricinctum among the 37 Fusarium strains tested. The activity of these five strains was similar to that of F. moniliforme var. subglutinans. However F. moniliforme and F. avenaceum ceased producing ice nuclei within a short time after subculture in liquid medium.