Abstract

The ED₅₀ value of antagonistic substance from Chaetomium globosum N0802 extracted with hexane was 157 µg/ml. This gave the highest inhibition of conidial production of Fusarium oxysporum f. sp. lycopersici causing tomato wilt var Sida. Crude hexane from Chaetomium lucknowense CLT and crude methanol fromTrichoderma harzianum PC01 gave ED₅₀ values of 188 and 192 µg/ml.  It clearly demonstrated that antagonistic substances from all tested fungi could be deformed and this could break the conidial cells.  The bio-agent formulations namely N0802, CLT and PC01 gave significantly highest disease reduction of tomato wilt which were 44.68, 36.28 and 41.01%, respectively, followed by prochoraz (21.95%). All tested bio-agent formulations could significantly increase the yield of tomato when compared to prochoraz and inoculated control. It is concluded that C. globosum, C.lucknowense and T. harzianum developed as bio-agent formulations namely N0802, CLT and PC01 and showed their abilities to control tomato wilt.

Key words: Fusarium oxysporum f. sp. lycopersici, Chaetomium globosum,Chaetomium lucknowense, Trichoderma harzianum, bio-agent formulations.

Abbreviation

DSI, Disease severity index; ITS, internal transcribed spacer; PDA,potato dextrose agar; PDB, potato-dextrose broth; PB, phosphate buffer; PCR,polymerase chain reaction; DMSO, dimethyl sulfoxide.