Mass production of Trichoderma harzianum for managing fusarium wilt of banana

Trichoderma spp. isolated from rhizosphere of banana (Musa sp.) from different areas of Tamil Nadu, India were evaluated under in vitro condition for their antagonistic potential against Fusarium oxysporum, the banana fusarium wilt pathogen. Trichoderma harzianum isolate Th-10 was the most effective in inhibiting the mycelial growth of fusarium in vitro. Out of five different organic substrates (rice bran, rice chaffy grain, farmyard manure, banana pseudostem and dried banana leaf) tested, dried banana leaf was the best carrier material to support T. harzianum growth. Strain Th-10 colonized the dried banana leaves within few days and produced high density of propagules (4.6×10³² cfu/g of leaf). Addition of jaggery (10% w/v) to the dried banana leaves increased the multiplication of T. harzianum which survived for >6 months on the stored substrate. When applied as dried formulation, the population of T. harzianum Th-10 increased from 10⁴ to 10 ¹³ cfu/g of soil within 60 days. In two field trials, soil application of T. harzianum Th-10 as dried formulation effectively controlled fusarium wilt with an efficacy comparable to that of the fungicide carbendazim.