Spore production and artificial inoculation techniques for Mycosphaerella fijiensis var. difformis

Abstract

Isolates of Mycosphaerella fijiensis var. difformis sporulated differently on 3.63% on Mycophil agar at 20, 25, and 30ºC. A large number of viable spores (2.1 – 13.1 × 106 conidia plate-1 maximum) were produced in 24 days by cultures incubated at 20ºC under 2.5 W m-2 of continues, cool-white, fluorescent light. A reliable quantitative inoculation technique was developed using a clean suspension of conidia produced under these conditions. Typical symptoms of black Sigatoka disease appeared on young banana leaves after a minimum of 16 days in a growth chamber at 25 ± 1ºC.