A New Biofungicide from China

A new biofungicide developed by the Chinese is effective against a broad scope of important plant diseases, yet is nontoxic to mammals and beneficial insects. In addition Antibiotic 120 (AB 120) not only acts as a systemic fungicide but also stimulates plant growth, increasing crop yields. It is considered a high research priority at the national level in China.

AB 120 is produced by fermenting the bacteria Streptomyces hygrospinosis var. beijingensis. The fermentation process can be done with locally available materials in 36 to 40 days. It is an alkaline soluble nucleoside that acts by blocking protein synthesis. The acute toxicity to mammals is very low, LD50 1,080 mg/kg.

Few studies have been done on AB 120, but known applications are already extensive. It is 70 to 90 percent effective against powdery mildew on melons, fruits, and vegetables and 60 to 85 percent effective against anthracnose, Colletotrichum sp., on the same crops. It is 70 to 90 percent effective against wilt disease on watermelon and vegetables, as well as sheath blight, Rhizoctonia solani, on corn and rice. It is effective against wheat stem rust, Puccinia graminis, citrus scab, Elsinoe fawcetti, and storage diseases of oranges and tangerines.

All crops tested showed yield increases. Pepper plants, Piper nigrum, treated with AB 120 yielded peppers with an almost 50-percent increase in weight over plants treated with carbendazim. AB 120 was also more effective than chemical treatments in controlling anthracnose smudge, Colletotrichum nigrum, on peppers.

AB 120 can be made into powder or liquid and applied in several ways: as a spray (100 ppm), a drench (100 to 150 ppm), a paint ( 200 to 500 ppm), or as a liquid additive to insecticides (100 to 120 ppm). A high-yield strain of AB 120 has been selected using protoplast fusion techniques.

AB 120 did not affect the life cycle of the predatory mite Phytoseiulus persimilis, and showed no chemical side effects.

Antbiotic 120, A New Chinese Biofungicide, IPM Practitioner, XIII(3) March 1991.