Mycosphaerella melonis

Gummy stem blight

Symptoms

Greyish green water-soaked streaks on infected stem and then become dry, coarse and tan. Stem tissue often crack and gummy ooze (pycnidia) exudes from the wound. Large lesions girdle the stem results in wilt in the heat of the day. 

Disease cycle

The fungus is seed and soil borne. The pathogen over winter for a year on infected crop residues in the absence of host plants. The fungus survives as dormant mycelium or chlamydospores. Both temperature (23-250C) and moisture (more than 85% humidity, rainfall and duration of leaf wetness from 1 to 10 hours) are critical for germination, sporulation and penetration of conidia and subsequent development of pathogen. Penetration of conidia is probably direct and through wounds.

Management

Use of disease-free seeds and crop rotation is essential to prevent serious crop losses.

Drenching spray of Veni GoKlean at the rate of 1.5 ml per litre of water one week after sowing manages the disease development. Drench 50-60ml final solution of Veni GoKlean to the root zone per plant.