Studies on interaction of nematode, Pratylenchus delattrei and fungal pathogen, Fusarium incarnatum associated with crossandra wilt in Tamil Nadu, India.

Abstract

Investigations were under taken in pot culture experiment to assess a possible interaction between fungal pathogen of crossandra, Fusarium incarnatum and lesion nematode Pratylenchus delattrei, at various population density combinations, time of inoculation and their effect on plant growth and wilt incidence of crossandra. Among varies pathogen and nematode population densities tested, the inoculation of pathogen load @3% w/v and nematode @ 1/g soil resulted in maximum reduction of plant growth parameters viz., shoot length (49.8%), shoot dry weight (52.6%), root length (47.0%), root dry weight (47.4%), and flower yield (82.6%). More over maximum root lesion index of 3.9/1-5 scale, wilt disease incidence of (50%) and nematode population up to 365 per 200 cc soil, were also recorded. Other experimental results revealed that the treatment involving inoculation of nematode prior to fungal pathogen recorded more disease incidence (58.3%), nematode (381/200cc) and pathogen (12.1×10), populations and there was significant reduction in root length, root weight, shoot height and shoot weight when compared with inoculation of pathogen and nematode simultaneously or inoculation of pathogen prior to nematode.