Ablastmycin, a new anti-piricularia antibiotic.

Kasugamycin which shows preventive effect on rice blast and low toxicity to plants and animals was discovered in a culture filtrate of Actinomycetes. The study on kasugamycin, as described in a previous paper15, established a new screening method to examine the inhibition of Piricularia oryzae growing in an acidic medium prepared with rice plant juice. Applying this screening method, a new antibiotic designated ablastmycin was found in the culture filtrate of a streptomyces. This antibiotic inhibits Piricularia oryzae in vitro at very low concentration and has low phytotoxicity, though the protective effect is reduced remarkably in the green house test. In this paper, the taxonomy of the str ptomyces producing this antibiotic, th condition for optimum production, isolation and purification procedures, and the properties are reported. Ablastmycin-Producing Organism