Interactions of Meloidogyne incognita, Ralstonia solanacearum and Phomopsis vexans on eggplant in sand mix and fly ash mix soils

•Eggplants grown in 25% sand mix soil had greater plant growth compared to plants grown in 25% fly ash mix soil.•Inoculation of Meloidogyne incognita 20 days prior to Ralstonia solanacearum and Phomopsis vexans caused a greater reduction in plant growth than inoculation of R. solanacearum plus P. vexans prior to M. incognita.•Plant inoculated in combination with 2 or more pathogens suffered greater plant growth reduction in 25 % sand amended soil than in 25 % fly ash amended soil.•Nematode multiplication and galling in higher in plants grown in 25 % sand amended soil than with 25 % fly ash soil.•R. solanacearum and P. vexans had adverse effects on galling and nematode multiplication.

Interactions of Meloidogyne incognita, Ralstonia solanacearum and Phomopsis vexans were studied on the growth of eggplant, chlorophyll and carotenoid contents of plants grown in 25% fly ash and 25% sand mix soil. Plants grown in 25% sand mix soil had greater plant growth compared to plants grown in 25% fly ash mix soil. Inoculation of plants with M. incognita, R. solanacearum or P. vexans reduced plant growth, chlorophyll and carotenoid contents in both types of soils. Combined inoculation of these pathogens caused a greater reduction in plant growth, chlorophyll and carotenoid contents than single inoculation. Inoculation of M. incognita 20 days prior to R. solanacearum and P. vexans caused a greater reduction in plant growth than inoculation of R. solanacearum plus P. vexans prior to M. incognita. Plants inoculated in combination with 2 or more pathogens suffered greater plant growth reduction in 25% sand amended soil than in 25% fly ash amended soil. Nematode multiplication and galling were higher in plants grown in 25% sand amended soil than with 25% fly ash soil. R. solanacearum and P. vexans had adverse effects on galling and nematode multiplication. Inoculation of R. solanacearum plus P. vexans prior to M. incognita caused maximum reduction in galling and nematode multiplication. Wilt and blight indices caused by R. solanacearum and P. vexans were 3 respectively. Wilt and blight indices were 5 when R. solanacearum and P. vexans were inoculated together or these were inoculated with M. incognita.