A study of violet root rot factors affecting production and growth of mycelial strands in Helicobasidium purpureum pat

摘要: Summary For this investigation, potato tubers were inoculated with 8·5 mm. disks cut from a growing colony of Helicobasidium purpureum on meat-malt extract agar, and buried in glass jars filled soil; maximum growth mycelial strands the inoculum disk was measured after some seven weeks by paper scale fitted to curved surface tuber. The distance covered frequency infection cushions decreased increase storage age Inoculum margin fungus (marginal disks) less effective for production than within circle drawn (submarginal disks). greater effectiveness submarginal related their density; progressive development mycelium marginal zone due infiltration new hyphae zone, as well branching original zone. Production also increased concentration nutrients especially that malt constituent. With five or six at 25°C., potency strand declined, but apparent staling effect did not occur colonies double depth agar (6 mm.). Transfer three four weeks' 25°C. laboratory temperature (15–20°C.) further 1–2 reduced more severely continued incubation same period. Growth 1 soil : 3 sand mixture soil. Soil acidity depressed medium low high moisture content, soil/sand mixture. This adverse shown over Rossi-Cholodny slides.