A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 2006

Fusarium wilt is a widely spread disease, that affects tomato production worldwide. The disease is suppressed mainly by the use of fungicides which affect the environmental health. The current study was therefore conducted to develop sustainable management measures for Fusarium wilt disease in tomato using selected biocontrol agents and fertility management in a laboratory and greenhouse study at the Asian Institute of Technology from August 2005 to Feb 2006. Trichoderma harzia unm from Myanmar, Thailand and Ethiopia, and T. koningii and T. pseudokoningii from Ethiopia were evaluated against Fusarium otysporun f. sp. lycopersici isolated from disease infected soils in Myanmar, and also obtained as pure cultures from the Mycology Department, Kasetsart University, Thailand, in a series of invitro and in-vivo studies. The two isolates of Fusarium wilt disease pathogen, F. oxvsporun f. sp. Ivcopercisi, obtained from disease infested soils in Myanmar and as pure cultures from Thailand showed similar morphology and pathological characteristics and disease development on tomato. All Trichoderma species used in the study, viz. T. harzianunr from Myanmar, Thailand and Ethiopia and T pseudokoringii, except T. koningii, inhibited both strains of F. oyspounr fsp. lycopercisi. The suppression of F. orysporum f. sp. lvcopercisi by T. koningii was weaker than the rest of the antagonists. T. harzianunr from Thailand was the best inhibitor, while T. psedokoningi and T harzianum (Myanmar) had satisfactory inhibition. Fusarium wilt decreased with T. harzianum (Myanmar and Ethiopia) and T. pseudokoningii from Ethiopia, while the other antagonist did not perform satisfactority under in-vivo, in which 1-10 ml rates of 3.2 x 107 spores/ml suspension concentration of T harzianunr and T. pseudokoningii were successful in the inhibition of F. oxvsporunr. T. harzianunrn from Ethiopia satisfactorily suppressed the disease at 20 ml dose of 3.2 x 107 spores/ml. Combined application of 102 kg/ha of N with P and K at higher rates of 4567.5 and 112 - 168 kg/ha, respectively, reduced the wilt percentage (by 48%) than other N rates and 22.5 and 56, kg/ha, respectively