Vegetable oils as protectants against nematode infections.

In this experiment, 0, 0.125, 0.25, 0.5, and 1.0 ml of each oil dissolved in 1 ml of 95 % ethanol was added to 1 kg of soil containing 370 P. penetrans per kg, and incorporated by shaking. After 10 days at 22 ± 3 C, a four-week-old tomato (Lycopersicon esculentum Mill cv. Bonny Best) seedling was planted in each of six 5-cm-diam plastic pots containing 100 g of treated or untreated infested soil. After 5 days at 22 C each root system (about 0.2 g) was washed free of soil and homogenized in a blender for 30 seconds. The number of free P. penetrans was determined. In another test, 1 ml of soybean oil was mixed with 1 kg of soil containing 850 Tylenchorhynchus dubius (Butschli) Filipjev. The soil was placed in 15-cm-diam plastic pots and incubated for 3 days at 22-25 C. T h e n annual rye grass (Lolium temulentum L.) was seeded. Twelve days later, T. dubius individuals in 100 g of soil from each pot were extracted by flotation (1) and counted. T o test possible use of these oils as root dips, tomato roots were dipped into water containing 0.25% corn oil and then planted in pasteurized soil or soil infested with P. penetrans (370/kg of soil). After growth in the greenhouse for 5 days at 22-25 C, tile roots were washed and homogenized in a blender for 30 seconds, and free P. penetrans were counted.