Non-chemical based management of Tylenchulus semipenetrans, a major threat to the citrus industry

Abstract

There is a vast variety of microbes available in soil performing diverse functions for plants including root colonization for protection against pathogens and nutrient acquisition. In the present study, efficacy of rhizospheric microbial strains and plant extracts were evaluated against citrus nematode for their nematicidal activity. Three different concentrations of plant extracts were evaluated in vitro, results depicts that 10% solution of Tagetes erecta (root) has given 46% the highest percentage mortality at 48hrs followed by Tagetes erecta (leaf) and Datura stramonium killed 41% and 37% nematodes respectively, similarly for 20% of plant extract in distilled water, the highest mortality rate was recorded for T. erecta (root) 68% followed by D. stramonium 47% and Acacia nilotica 44% at 48hrs of application. While using a higher concentration 30% of SS. the percentage mortality elevated multifold i.e.  Marigold root has killed maximum 76% nematodes followed by Marigold leaves and Dhatura with mortality rate 69% and 58% respectively at 48 hrs of interval. While Eucalyptus killed lowest no of nematodes. Additionally, five bacterial isolates were evaluated for their nematicidal activity. Results indicated that for bacterial cell suspension, Pseudomonas putida has shown maximum mortality rate at 84% followed by Bacillus subtilis 73% & Pseudomonas geniculata 65% at 48hrs of interval. Similarly, in the 2^nd set of experiment bacterial culture filtrates has exhibited promising results, maximum mortality rate was recorded for Bacillus spp. 81% followed by B. subtilis 76%, Ps putida 63%, after 48hrs of incubation. Moreover, an insight investigation of bacterial extracellular metabolites and plant extracts would enable researchers to develop purposeful products and compositions