Effects on nematodes produced by certain types of electrical energies

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Virginia Polytechnic Institute

This investigation, concerning the effects of electricity on nematodes, was conducted in order to find a method of controlling the root-knot nematode in the tobacco field by the use of electricity.

The output of a simple induction coil (p. 13 and 37), a 220 Volt 60 cycle current (p. 44), and a 27.12 megacycle transmitter (p. 55) were used to treat the nematodes. Since the nematodes are microscopic, they were treated in the mediums of soil, tap water, distilled water, and distilled water filtered through tobacco soil. The width of the treated area varied trom ½ inch to 12 inches, and the time of treatment varied from 10 seconds to 120 seconds.

Two methods were used to determine whether or not the nematodes were killed by the treatments. In the first method (p. 13), the treated soil was planted with okra and tomato seeds which would quickly develop a root system large enough to determine whether or not root-knot infections were present. In the second method (p. 34), the nematode was separated from the and observed in water under a microscope. Results of the treatments were determined more readily by the second method. However, this method required much patience by the operator, and an adequate technique to carry out the second method has not as yet been completely developed.

By exposing the nematodes to heat (p. 47) and by comparing the effect of heat alone on the nematodes with the effects of other electrical treatments, it was shown that the heat generated by the electrical treatment provided the lethal effect on the nematodes.

An analysis was made of an induction coil showing its output to be AC. An investigation was made to find the conductivity of Granville sandy loam tobacco soil at different moisture levels. The equation Y: 47 x 10⁴ X-1.29 (10) Y: resistance in ohms X: % of moisture content of the soil shoving the relationship between conductivity and per cent moisture was determined from this test.

Because of the scope of this problem of controlling nematodes by electrical means, the author had to conduct only preliminary investigations. However, it is the author's belief that the only way to control nematodes by electricity, and not heat the soil appreciably, is to ionize the chemical in the living cells of the eelworm. To ionize chemicals in the living cells of the nematode would necessitate the application of electrical energy with a frequency high enough to produce x-rays or gamma rays.