Comparision of nematicides applied as root-dips or soil drenches for the control of Meloidogyne incognita on tomato


  • Sudesh Ahuja


Several different nematicides were assessed for the control of Meloidogyne incognita (Kofoid et White) Chitw. in a field crop of tomato (Lycopersicon esculentum Mull). The roots of 4 week tomato seedlings (Var. S 12) were dipped for 60 min. in aqueous emulsions or suspensions of the nematicides and then planted in the field in 50 plant plots, with five replications of each treatment (Table O. The same nematicides were also applied as soil drenches, 100 ml aqueous solution, at each planting station in another series of replicated treatments (Table O. The density of the nematode population before treatment was 255 larvae per 250 ml soil. Forty five days after transplanting 25 plants in each plot were uprooted carefully and the severity of galling assessed on the basis of a root-knot index, 1 = no galling, 2 < 25%; 3 = 25-50%; 4 = 50-75%; 5 = 75-100%; 6 = confluent galling. The remaining plants were uplifted 120 days after transplanting and again assessed for root galling. Fruit was picked on five occasions as it ripened and yields were recorded. At 45 days after transplanting, oxamyl and aldicarb treatments showed improved root growth compared with all other treatments. At 120 days after transplanting the oxamyl treatments decreased root galling and improved plant growth and yield in comparison with all other treatments; the soil drench application was better than the transplant dips (Table O. Many of the nematicide treatments were phytotoxic.