Evaluation different culture media for growth of Phytophthora colocasiae Racib. Causal agent of leaf blight disease of Colocasia under in vivo conditions

Abstract

Phytophthora colocasiae Racib. was recently the most important pathogen of Colocasia (Colocasia esculenta) in India and no more study is yet done on its culture growth on common medium. Eight artificial media, Oat meal agar medium (OMA), Potato dextrose agar medium (PDA), Host leaf extract agar medium (HLEA), Carrot agar medium (CAM), Tomato agar medium (TAM), Soybean agar medium (SAM), Water agar medium (WAM) & V8 agar medium (V8) were assessed in vitro to determine the growth characteristics of the pathogen. After evaluation for growth of the pathogen, on oat meal agar medium (OMA) mycelial disks from pure culture were placed on each culture medium and incubated for 7 days at room temperature (27 ±1 °C). OMA was the most effective medium as it recorded maximum (90mm) of mycelial growth of the pathogen, after 7 days of inoculation. It was followed by HLEA (87.67mm), CAM (87.33mm), PDA (84.67mm), TAM (54.67mm), WAM (41mm), SAM (38mm) and V8 (28.33mm) was the least effective medium. The mycelium was hyaline, coenocytic, sporangia elongated lemon to pear shaped with a conspicuous lid like structure at the distal end.