Utilization of Rhizobacteria and Spent Mushroom Compost for the Management of Bacterial Wilt of Potato

Abstract

Potato (Solanum tuberosum L.) is the fourth most important staple food in the world after wheat (Triticum aestivum L.), rice (Oryza sativa L.) and maize (Zea mays L.). In Pakistan, potato crop is cultivated over an area of 191.6 million hectares. On an average potato production in Pakistan is 20 tonnes per hectare.A target has set by The Government of Pakistan to produce about 4.871 million tons potatoes during Rabi Season 2020-21. (Federal Committee on Agriculture FCA) The potato production exceeds 376 million tonnes harvested from an area of 19.25 million hectares in the world (FAOSTAT 2018). Ralstonia solanacearum causing bacterial wilt is a major threat to potato production. Management through biocontrol agents is one of the best methods that can replace synthetic chemical-based formulations. In the current study combine effect of antagonist rhizobacteria as biocontrol agent and spent mushroom compost as biofertilizer were tested against bacterial wilt disease pathogen. Potato plant samples infected with R. solanacearum and rhizobacteria were collected from potato growing fields in Rawalpindi. Out of twenty tested antagonistic rhizobacterial isolates, only three viz., Rh10, Rh12 and Rh 15 showed maximum inhibitory effect against R. solanacearum. In another experiment different combinations of treatments containing rhizobacteria alone or combined with fresh and spent mushroom composts were also tested against the bacterial wilt pathogen under laboratory conditions. Combination of rhizobacteria along with weathered compost (T5) reduced the disease incidence to 15.92 % when compared against 77.81 % in control after six weeks. Significant increase in plant height up to 41.83 cm was also observed as compared to control viz., 35.5cm. Similarly, T2 (only fresh compost), T3 (containing fresh compost along with rhizobacteria) and T4 (rhizobacteria along with weathered compost) also showed better results as compared to against control (T0) where there was no application of rhizobacteria and compost. Application of rhizobacterial along with spent mushroom compost can significantly reduce the disease incidence along with the improvement in plant growth parameters.