Usage of green manure plants as cover-crops in controlling root-knot nematode, Meloidogyne incognita (Kofoid and White) on tomato, Lyco-persicon esculentum (Mill.)

Abstract

This study was conducted to determine the nematicidal effect of aqueous extractions of dry plant materials, Tithonia diversifolia, Gliricidia sepium and Tagetes erecta on juveniles of Meloidogyne incognita (Kofoid and White) and to determine the effect of dry leaves of wild sunflower, dry leaves of Gliri-cidia, and dry plant parts of marigold as cover crops on the growth of potted tomato, Lycopersicon esculentum (Mill.) infested with M. incognita. Nemati-cidal effect of aqueous extracts of T. diversifolia, G. sepium and T. erecta (20 g/ 100 mL w/v) were evaluated at 0.05 g/mL, 0.1 g/mL and 0.2 g/mL concentrations in the laboratory bioassay. Results revealed that 0.1 g/ mL and 0.2 g/ mL concentration of T. erecta and 0.2 g/mL concentration of T. diversifolia were very effective in juvenile mortality by over 50% within 48 hours com-pared to other treatments. T. erecta plant parts were the most effective causing above 70% juvenile mortality in 48 hours. M. incognita infested potted tomato plants supplement with dry plant parts of Marigold (2% w/w) showed; significantly higher number of green leaves (P=0.000, F=10.95); significantly lower number of yellow leaves (P=0.001, F=6.78); significantly high-er plant height (P=0.000, F=8.90), stem diameter (P=0.000, F=11.83), root length (P=0.000, F=14.71) and root weight (P=0.000, F=15.08); significantly lower number of root galls (P=0.000, F=116.74), gall index (P=0.000, F=95.80) and significantly lower population of M. incognita in soil (P=0.000, F=24.78) compared to other treatments. This study concludes that addition of botani-cals as cover crops enhanced plant growth and significantly reduced root-knot infestation in tomato plants.