Efficacy of soil solarization and selected organic amendments for the control of root-knot nematodes in African nightshades

Root-knot nematodes (RKN) (Meloidogyne spp.) causes up to 80 % yield losses in infected vegetables. The efficacy of solarizing soils amended with or without selected organic amendments for the control of the RKN on African nightshade (AFNS) Solanum villosum was evaluated in field experiment at Ng’enyilel, Uasin Gishu County, Kenya. Solarizing soils amended with cattle manure, pymarc and T. diversifolia organic materials resulted into higher shoot height and biomass in S. villosum. Tithonia diversifolia was the best amendment, followed by cattle manure and pymarc in improving plant growth. In addition, nematode populations were reduced greatly in solarized amended soils compared to non-solarized soils. Solarized soils amended with cattle manure (Cm), Tithonia diversifolia (Td) and pymarc (Pm) reduced RKN population and damage significantly compared with non-solarized and non-amended controls. Solarization improved the efficacy of organic amendments against RKN on S. villosum with the highest percentage J2 control being obtained by cattle manure (84.3 %) followed by pymarc (57.22 %), T. diversifolia (10.83 %) and unamended controls (3.6 %). Reproduction was lower on Cm, Pm and Td amended soils while galling index ranged from 0.7 to 2.2 in solarized soils compared to 1.4 – 5.0 in non-solarized soils. Solarized soils had higher soil temperature relative to non-solarized soils. Solarizing soils amended with organic materials is an ideal integrated pest management strategy for combating RKN infecting AFNS. Soil solarization combined with T. diversifolia compost, cattle manure and pymarc amendments could be used for RKN management and improving soil fertility for production of AFNS