Preliminary Investigation of Trichoderma asperellum’s Culture and Extracts Against Black Rot of Orchid

Abstract

The effect of Trichoderma asperellum against black rot pathogen of orchid caused by Phytophthora palmivora (Butl.) Butl. was investigated. Eleven isolates of P. palmivora were isolated form leaves by tissue transplanting technique and were proved for their pathogenicity by detached leaves technique. The results showed that isolate V04 gave the highest virulence for disease incidence. T. asperellum was tested against mycelial growth of P. palmivora V04 by bi-culture test and crude extract methods. Bi-culture test showed that T. asperellum could inhibit mycelial growth at 71.67%. Crudeextracts were extracted from T. asperellum withhexane, ethyl acetate and methanol. Crude extract which was extracted with methanol gave the best mycelial growth inhibition at the concentration of 1,000 µg/ml (p ≤ 0.05) and the effective dose (ED50) was 1,591.61 µg/ml.