Utilizing Soybean Milk to Culture Soybean Pathogens

Liquid and semi-solid culture media are used to maintain and proliferate bacteria, fungi, and Oomycetes for research in microbiology and plant pathology. In this study, a comparison was made between soybean milk medium, also referred to as soymilk, and media traditionally used for culturing soybean pathogens to determine if soymilk medium was an effective medium for growth of Colletotrichum truncatum, Fusarium virguliforme, Macrophomina phaseolina, Passalora sojina, Phomopsis longicolla, Phytophthora sojae, Pythium irregulare, Rhizoctonia solani, and Sclerotinia sclerotiorum. Based on radial mycelial colony growth rates, C. sojina grew significantly (P < 0.05) faster on soymilk dextrose agar (SDA) than on V-8 agar, and C. truncatum and F. virguliforme grew significantly (P < 0.05) faster on SDA than potato dextrose agar (PDA). Significantly (P < 0.001) greater masses of sclerotia were produced by S. sclerotiorum grown on SDA as compared to PDA. Soymilk used with agar or used alone as a broth may be an option for replacing more expensive processed culture media.