EFFECTS OF NEMATICIDES ON POPULATION OF PRATYLENCHUS PENETRANS AND GROWTH OF FLUE-CURED TOBACCO

Field studies were conducted an loamy sand at Tamscu farm, Delhi, Onta rio, to compare the spring ridge application of Telone C17 at 73 and 1 01 L/ha, Vorlex at 28 and 84 L/ha, Vorlex CP at 50 L/ha, and spring ro tovated application of oxamyl at 2.24 kg/ha respectively for the contr ol of Pratylenchus penetrans (Cobb) Filip. and Stek., and for effects on the yield and quality of flue-cured tobacco. Experiments were condu cted on May 9 in an area that had been summer fallowed in previous yea r. Nematode densities of P. penetrans per kilogram of soil were lower than other treatments and controls with Telone C17 at 73 L/ha treated plots on May 24; with Vorlex at 28 L on June 7; Vorlex at 84 L on May 24 and on June 7; Vorlex CP on June 7, and with oxamyl on Sept. 6. The nematode population counts per gram dry weight of root were lower wit h Telone C17 at 73 L/ha on June 7, July 5, and at 101 L/ha on July 5; with Vorlex at 28 L/ha on June 7, July 5, and Sept. 6; with Vorlex at 84 L/ha on June 7, June 21, July 5 and Sept. 6, and with Vorlex CP at 50 L/ha on June 7, July 5 and Sept. 6 in the ridged soil. The populati on was lower with oxamyl on June 21, July 5, and Sept. 6 in the rotova ted soils. There was no difference in the agronomic data on yield, ind ices of grade, crop and maturity, while tobacco plant height and dry w eight in the ridged farming were greater with treatments of Vorlex at 84 L and Vorlex CP at 50 L/ha. The ridged farming had greater yield of tobacco than rotovated farming. Vorlex was the most effective of all nematicides used in the experiment.