Pathogenicity of Helicotylenchus indicus Siddiqi, 1963 on papaya and impact of some bio-organic materials

Two pot experiments were conducted to determine the growth response of papaya, ‘Solo’ and H. indicus reproduction in relation to different levels of nematode inocula (0, 1000, 2000, 4000, 8000 and 12000 nematode/pot) and impact of some commercial products, e.g. Bio Tonic®, Hundz Soil®, Nemakey-N™, Nemastop® and Nubtea® on nematode management, plant growth and NPK contents. As increase nematode density to 4000 and up to 12000 nematode/pot, significant reductions in plant length, fresh or dry mass were detected. The highest reduction in plant growth was achieved by density of 12000 nematode/pot. Most inoculation levels reduced plant contents of N and K regardless to nematode density. Tremendous increase in plant content of P was obtained by 4000 and 12000 nematode/pot. The nematode build up was decreased by increasing the nematode density. All treatments significantly improved the plant criteria. Significant increase of shoot parameters was obvious in Nubtea® treatment. Nemastop® had less value of shoot parameters. Negative response was recorded in P content in all treatments. There were no significant differences among treatments in plant content of N except Nubtea® treatment. The least value of K was found in Nemastop® treatment. The Nemakey-N™ overwhelmed all treatments in reducing all nematode criteria.