EFFECTS OF DEEP FUMIGATION ON PRATYLENCHUS PENETRANS, FLUE-CURED TOBACCO, AND SOIL NITRATE CONTENT

Abstract

Row applications of Telone (1,3-dichloropropene and related chlorinated C3 hydrocarbons), at 45 and 90 liters/ha were injected 15, 30, and 45 cm below the soil surface and ridged up an additional 15 cm. Telone, at 90 liters/ha injected at 15 cm, gave the best control of the root-lesion nematode Pratylenchus penetrans (Cobb) Filip. and Stek. 1941, in the top 0–20 cm of soil. The degree of nematode control in the top 20 cm of soil was inversely correlated with injection depth. Though the degree of nematode control with 45 liters/ha of Telone at 30 cm was considerably less in the 0–20-cm soil layer than with the 90-liter rate at the 15-cm depth, the yields of flue-cured tobacco were about equal for both treatments. Good control of nematodes in the 20–40-cm soil layer was obtained with both rates of Telone regardless of injection depth. At the recommended rate of 90 liters/ha there appeared to be no advantage to injecting Telone deeper than 15 cm. Where no Telone was applied, the levels of NO−3-N in the soil in June were higher, and yields of tobacco tended to be lower.