Inhibitory influence of biocontrol agents, plant oils and an inorganic salt on Mycosphaerella fijiensis and Cordana musae, the causal pathogen of black sigatoka and leaf spot of banana

The search for alternatives to chemical treatments to control the causal pathogens of black sigatoka and Cordana leaf spot in banana was studied in vitro. We examined the effect of biocontrol agents, plant oils, and an inorganic salt on the mycelium growth ofMycosphaerella fijiensis and Cordana musae for 10 weeks. Trichoderma harzianumDGA01 and Bacillus amyloliquefaciens DG14 inhibited the development of M. fijiensisthroughout the duration of observation while Serenade ASO (Bacillus subtilis 1.34% EC) gave total control for six weeks. Piper betel oil (2.5% EC), garlic oil (15% EC), capsicum oil (20% EC) were not successful in killing dormant mycelium but do cause significant delay in development of M. fijiensis by 37, 9, and 43%, respectively. Potassium bicarbonate (14% EC) restricted the growth of M. fijiensis by 43%. Meanwhile, T. harzianum DGA01, B. amyloliquefaciens DG14, and Serenade ASO sustained total control of mycelium development of C. musae in 10 weeks while piper betel oil had only limited the mycelium growth by 60%, garlic oil and capsicum oil by 20%, and potassium bicarbonate by 28%.   Key words: Banana, biocontrol agent, inorganic salt, plant oil, black sigatoka, Cordana leaf spo