EVALUATION OF Trichoderma harzianum IN CONTROLLING DAMPING OFF AND FOOT ROT OF CHILLI

Abstract

A set of five experiments were designed to evaluate the efficacy of T. harzianum and its shelf life formulated in Chick pea (Cicer arietinum) husk during March 2016 to June 2017 at HSTU, Dinajpur. The major soil borne pathogens, Sclerotium rolfsii and Fusarium oxysporum causing foot rot and damping off were used for this study. The pathogens were isolated from infected tomato plants and potato tuber, respectively grown in the central research field and identified morphologically. In the first dual culture technique, T. harzianum inhibited the mycelial growth of S. rolfsii and F. oxysporum 60% and 80%, respectively. In pot study (2nd, 3rd and 4th experiments), T. harzianum was evaluated against S. rolfsii and F. oxysporum in controlling damping off and foot rot of chilli seedlings following five treatments applied with T. harzianum formulations @ 20g/kg of soil and spore suspension sprayed as 2.45×107 cfu/ml in each of pot experiments. The data were recorded on percent seed germination, pre-emergence death, foot rot, damping off at 7 and 14 days after sowing (DAS) while shoot length, root length, shoot weight, root weight and vigor index were recorded at 14 DAS. The results revealed that in all pot studies, the treatment T4, (S. rolfsii inoculum + T. harzianum formulation + T. harzianum suspension) in the 2nd experiment, (F. oxysporum inoculum + T. harzianum formulation + T. harzianum suspension) in the 3rd experiment and (S. rolfsii inoculum + F. oxysporum inoculum + T. harzianum formulation + T. harzianum suspension) in the 4th experiment reduced highest amount of foot rot (74.29-84.61%) and damping off (75-81.8%) of chilli seedlings at 14 DAS. It also increases the seed germination, seedling height, weight and vigor index regarding 7 and 14 DAS over other treatments. In the 5th experiment, the formulated T. harzianum using chick pea husk were packaged @ 50g/ polyethylene bag and stored in different environmental conditions viz., T1: Table Top, T2: Refrigerator (40 C), T3: Wooden Shelve, T4: Tin Container and T5: Wooden Locker with three replications. The initial population (at 0-day) of T. harzianum was recorded 22×106 cfu/g and counted up to 120 days after incubation (DAI) at 15-day intervals using serial dilution plate technique. Results revealed that Table Top storage at room temperature gave highest cfu (126.3×106 ) at 60 DAI followed by moderately effective Wooden Shelve and Refrigerator storage while the lowest viable spores were recorded in Wooden Locker (73×106 ) and Tin Container (66×106 ). Finally, it may be concluded that formulated T. harzianum applied @ 20g/kg of soil and spore suspension as 2.45×107 cfu/ml resulted statistically significant against S. rolfsii and F. oxysporum causing damping off and foot rot of chilli with higher germination and vigor index. Moreover, the shelf life of the formulated T. harzianum was statistically higher (126.3×106 cfu/g) in case of Table Top storage.