Primary Study on Phytotoxin Production Conditions of Tobacco Alternaria alternata GL-6

To make sure the phytotoxin produced conditions of tobacco Alternaria alternata, GL-6 isolate were cultured under the different conditions and the crude toxin liqiud was inoculated on the tobacco seedling. The analysis result showed that when the tested fungus was cultured in potato dextrose liquid medium for 14?d, it could produce a large amount of the toxin which could bring about the tobacco brown spot disease. Both cultural methods can be used for extracting phytotoxin from GL-6.