IN VITRO EFFICACY OF TRICHODERMA ISOLATES AGAINST SOME FUNGI CAUSING FUNGAL ROT DISEASE OF TOMATO

Jahangir Abdullah Koka*, Abdul Hamid Wani, Mohd Yaqub Bhat and Shazia Parveen. Section of Mycology and Plant Pathology, Department of Botany, University of Kashmir, Hazratbal, Srinagar, Kashmir. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

Biological control has been found efficient eco-friendly approach for the management of several fungal diseases caused by pathogenic fungi. Therefore, present study was carried out to evaluate the in vitro efficacy of some Trichoderma isolates against the pathogenic fungi, Alternaria alternata (Fr.) Keissl., Penicillium sp and Aspergillus niger Van Tiegh known to infect tomato fruits in Kashmir. It was observed from the results that all the Trichoderma isolates brought about significant inhibition in the mycelial growth. The inhibition in mycelial growth of Alternaria alternata, by PPT3 isolate of Trichoderma was 26.79%, followed by isolate PPT1 (19.47%) and isolate PPT2 (14.64%) of Trichoderma respectively. Likewise, the highest inhibition in mycelial growth of Penicillium sp. was shown by isolate PPT3 (34.36%) followed by isolate PPT2 (23.44%) and by isolate PPT1 (9.37%) respectively. In case of Aspergillus niger, the inhibition in mycelial growth was highest by isolate PPT3 (42.5%) followed by isolate PPT1 (36.67%) and by isolate PPT2 (31.67) respectively. The results indicate that different local isolates of Trichoderma proved effective against the tested pathogenic fungi and can be evaluated further for their antifungal activity against other fungi.

Introduction:-
Tomato (Lycopersicon esculentum Mill.) is a member of the family Solanaceae which comprises short-lived perennial herbaceous plants. It is one of the most popular vegetable crops widely grown for its edible fruits, high nutritive values and also for its diversified uses (Afroz et al., 2008;Ewulo et al., 2008). They are important source of vitamins and important cash crop for both small holders and medium scale commercial farmers (Ana et al., 2003). The fruit also contains plenty of antioxidant carotenoid lycopene that has recently attracted interest because of its role in preventing cancer heart disease and muscular degeneration (Wener, 2008). Several pathogenic fungi are known to cause damage to tomato especially under storage conditions and also on the aerial parts of the plants. The main postharvest disease of tomato caused by various pathogenic fungi are Rhizopus stolonifer (Stevens et al., 1997;Schena et al., 1999), Botrytis cinerea (Lee et al., 2006) and Alternaria alternata (Feng and Zheng, 2007). A. alternata is a saprophytic pathogen of tomato causing postharvest black rot at high frequency (Akhtar et al. 1994). Harvested fruits and vegetables decay due to fungal infestation is the main cause of major losses in food production. Postharvest decay of fruits and vegetables can be traced to infections, occur either between flowering and fruit maturity or during harvesting and subsequent handling and storage (Eckert and Ogawa 1988). The loss resulting ISSN: 2320-5407

Int. J. Adv. Res. 5(3), 2050-2053
2051 from these infections have been reduced primarily by applying fungicides in the field or after harvest (Eckert and Ogawa 1988).
Trichoderma spp. is the most widely studied biocontrol agents (BCAs) against plant pathogens because of their ability to reduce the population of soil borne plant pathogens (Papavizas, 1985). They are soil borne fungi and show significant activity against a wide range of plant pathogenic fungi (Elad et al., 1982). Mechanism used by Trichoderma spp. for control of plant pathogen includes competition, mycoparasitism, antibiosis and induced resistance of the plant host (Chet, 1987;Schirmbock et al., 1994).
Trichoderma is one of the common fungal biocontrol agent is being used worldwide for suitable management of various foliar and soil borne plant pathogens. (Dominguesa et al., 2000). Therefore, the objective of the present investigation was to assess the efficacy of local isolates of Trichoderma under in vitro condition against some fungal pathogens isolated from tomato fruits.

Materials and Methods:-
Tomato (Lycopersicon esculentum Mill.) fruits were obtained from different vegetable local markets of Kashmir Valley. Samples of infected fruits were brought to the laboratory in clean polythene bags and these samples were either used immediately or stored at 10 o C in the laboratory for different pathological studies. Small portions of rotted tissues were isolated aseptically from the diseased tomato fruits and transferred to Potato Dextrose Agar (PDA) medium. Pure colony cultures were obtained by sub-culturing the isolated fungi such as Alternaria alternata (Fr.) Keissl., Penicillium sp and Aspergillus niger Van Tiegh, in separate Petri plates containing the same medium. The pathogen was identified by their morphological, reproductive and cultural characteristics (Ellis, 1971; Barnett and Hunter, 1972;Watanabe, 2002;Gilman, 2008). For pathogenicity, pathogens were re-inoculated after isolation onto the healthy pear fruits (Tomkin and Trout, 1931). Then all the fruits were kept in clean polythene bags and incubated at 25+2 o C for ten days. These pathogenicity tests were used for the identification of plant pathogens and to confirm the detection of a particular disease. Identification of the disease and the pathogen was done following Koch's postulates.
Isolates of Trichoderma were isolated from rhizospheric soil of the tomato plant following serial dilution method (Brown 2004  Where dc = average diameter of fungal colony in control, and dt= average diameter of fungal colony in treatment group.

Results:-
It was observed from the results ( Table 1) that isolate PPT-3 of Trichoderma inhibited the mycelial growth of Alternaria alternata to an extent of 26.79 per cent. This was followed by Trichoderma isolates PPT-1 (19.47%) and PPT-2 (14.64%) respectively. Likewise, growth inhibition of Penicillium sp by Trichoderma isolates PPT-1 was 9.37%, by PPT-2 was 23.44% and by PPT-3 was 34.36% respectively and inhibition in mycelial growth of Aspergillus niger due to Trichoderma isolates, PPT1, PPT2 and PPT3 were 36.67%, 31.67% and 42.5% respectively.
The maximum growth inhibition of Alternaria alternata and Aspergillus niger was due to Trichoderma isolate, PPT3 followed by isolate PPT1 and isolate PPT2 respectively. Whereas, isolate PPT3 caused maximum growth inhibition of Penicillium sp. However, the least inhibition in mycelial growth of pathogenic fungi was observed by Trichoderma isolate, PPT1.  Dharmaputra et al. (1994) also tested two isolates of T. harzianum and one isolates of T. viride against Ganoderma and found that all isolates inhibited the mycelial growth of the pathogen, but T. harzianum (isolates B 10-1) showed the best performance. Etabarian (2006) reported that T. viridi (MO) reduced the colony area of Macrophomina phaseoli by 19.2 and 34.9% using the dual culture and cellophane methods, respectively. Intana et al. (2007) reported the efficacy of three mutant and two wild type strains of T. harzianum against Colletotrichum capsicis, causal agent of anthracnose of chili. The present study suggests that Trichoderma sp. effectively inhibits the growth of fungi causing rot of tomato, hence can be used as a biocontrol agent against rot diseases of vegetables. Bashar and Rai (1994) studied the three isolates of Trichoderma viz.,Trichoderma harzianum Refai, Trichoderma hamatum and T. viride Pers. were selected to test their antagonistic potential against the pathogens following dual culture technique. However, further investigation is needed for the efficacy of these local isolates of Trichoderma against fungal pathogens.