Co-application of bio-organic and fly ash: strategies for managing root-knot nematode, Meloidogyne incognita in papaya (Carica papaya) crop

Abstract

This study investigates the effects of various bio-organic amendments on the growth, physiological parameters, and nematode infestation in papaya crop. Treatments included fly ash (FA) at different concentrations (10%, 20% and 30%) inoculated with 2000 juveniles of Meloidogyne incognita (MI), neem cake (NC) at 50g and 100g inoculated with MI, and Trichoderma viride (Tv) at 1g and 2g inoculated with MI juveniles. Results showed significant improvements in shoot length, root length, fresh and dry weights, and chlorophyll content in plants treated with bio-organic and FA amendments compared to the untreated inoculated control (UIC). The highest shoot length was observed in the untreated un-inoculated control (UUC) at 55 cm, while UIC had the lowest at 32 cm. Treatments with 100g NC + MI and 2g Tv + MI resulted in shoot lengths of 52 cm and 54 cm, respectively, and increases of 62.5% and 68.8% compared to UIC. Root length was significantly improved with 100g NC + MI and 2g Tv + MI, reaching 43 cm and 47 cm, respectively, representing increases of 230.8% and 261.5% compared to UIC. Chlorophyll-a content increased to 2.04 mg/g and 2.113 mg/g, while chlorophyll-b content reached 1.06 mg/g and 1.15 mg/g in treatments with 100g NC + MI and 2g Tv + MI, respectively. Total chlorophyll content was highest at 3.1 mg/g with 100g NC + MI. Nematode infestation was markedly reduced, with 100g NC + MI and 2g Tv + MI showed no egg masses and root-knot indices (GI) of 2 and 2, respectively. Overall, bio-organic amendments, particularly higher concentrations of neem cake and T. viride, significantly enhance plant growth and reduce nematode infestation, suggesting their potential as sustainable agricultural practices for managing plant parasitic nematodes.