Effect of Temperature and Some Substrate onTeliospore Germination of Sugarcane Smut and Inoculation Methods on Infection by Ustilago Scitaminea

Abstract

Temperature for teliospore germination of Ustilago scitaminea was ranging from 15 to 40 C and 15 to 35 C for mycelial growth, with 25 C for optimum germination and growth. Telio¬spores germinated within 3.50, 6.10, 4.00 and 4.50 hr after incubation in extracts of sugarcane bud, soil, sugarcane leaf and sugarcane root, respectively. Sugarcane bud showed highest percentage germination (20.16%) at 6 hr incubation. Teliospores germinated well in 1.5% dextrose and sucrose substrate and the fungus grew well on potato dextrose agar, V-8 juice agar, malt extract agar and glucose peptone agar at room temperature (30 ± 4 C) when inoculated with teliospores. Six methods of artificial inoculation techniques were studied in both greenhouse and field conditions. The best method was injected weekly for 5 weeks with 2 ml teliospore or sporidial sus¬pensions (106 -107 spores/ml) into one week old shoot.