A Brief Report on the Tank-Mixture Method of Using Oil Spray
Author: SMITH, RALPH H.
Source: Journal of Economic Entomology, Volume 23, Number 2, April 1930 , pp. 376-382(7)
Publisher: Entomological Society of America
Abstract:With over 35 brands of highly refined oil emulsions on the market for use in the spraying of citrus trees in southern California, backed in general by methods of "high-pressure" salesmanship, and with widely variable results in insect control and injury to trees, a definite need existed for a formula whereby the grower who so desired could use a spray of known composition. Pursuant to this need investigations showed that, when the type of oil best suited for citrus spraying is used, the principal quality of the spray mixture is that which relates to the quantity of oil deposited a.nd the uniformity of the oil coverage. Tests showed that it is entirely practicable, with modern orchard sprayers, to maintain a uniform mixture of water, emulsifier, and pure oil, added separately to the spray tank, by using large-sized blades on the agitators and increasing the speed of the agitator shaft to about 225 r.p.m. By dyeing the spray oil and placing a piece of heavy-walled glass tubing at each end of the spray hose, one between the spray tank and the hose and the other between the hose and the spray nozzle, the fact was determined that the oil globules do not coalesce or float out to any material extent in passing through the spray hose. Microscopic studies of samples taken from the spray tank and from the spray nozzle showed that even though globules of relatively large size might pass through the hose, these are broken into very small globules, quite comparable to those in proprietary emulsions, as a result of being forced through the nozzle under a pressure of 300 pounds.
Studies on the quantity of oil deposited on glass and citrus leaves, 25 square inches being used as the unit of area, showed that certain proprietary emulsions deposited three times as much oil as others. The average amount deposited on the glass was 21 milligrams. Tests with the tank mixture, using calcium caseinate spreader at the rate of ½ pound to 100 gallons of water, showed a deposit of 22 milligrams of oil. All tests were made with two percent of actual oil in the spray.
Document Type: Research Article
Publication date: April 1, 1930
- Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
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