INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 37 
TIMBO 
See Rotenone-Containing Roots (pp. 30-82). 
TOBACCO DUST 
Tobacco dust is finely ground tobacco refuse and is a native product. 
Fresh tobacco dust containing at least 1 percent of nicotine is apphed 
as a mulch on the soil surface about rose plants to destroy larvae of the 
rose midge as they drop to the ground to pupate in the soil. This 
material, as a surface mulch or worked into the top inch layer of soil, 
is also a remedy for the larvae of fungus gnats and for root aphids. It 
is sometimes used undiluted as a dust to control thrips and aphids on 
various plants. Tobacco dust is also used as a diluent for pyrethrum 
powder, rotenone root powder, and other insecticidal dusts. 
VEGETABLE OILS 
Vegetable oils are used as insecticides or with them in a number of 
ways. Emulsifiers for mineral oil have been made from olive oil, 
castor oil, and corn oil. Cottonseed oil is used with paradichloro- 
benzene for the control of the lesser peach borer. Linseed oil and 
crude soybean oil have been used as adhesives for lead arsenate or 
nicotine bentonite sprays applied to fruit trees. These oils are also 
partially effective against the eggs of the codling moth and certain 
other insects. 
Peanut oil or soybean oil is used (1 or 2 percent) in the preparation 
of dusts containing derris or cube for the control of the pea aphid. 
Sulfonated castor oil, commercially known as Turkey-red oil, is a 
viscous, transparent lght-yellow liquid. It is one of the wetting and 
emulsifying agents used in the preparation of various sprays. In a 
derris-pyrethrum spray used for the control of red spiders and thrips 
on greenhouse and garden plants, it is added at the rate of 1 part to 
300 or 400 parts of the spray. 
WETTING OR SPREADING AGENTS 
In addition to soap, which is discussed on page 33, many other mate- 
rials are used as wetting and emulsifying agents. Sold under various 
trade names, some of them are chemically known as—sodium mono- 
sulfonate of monobutyldiphenyl, sodium oleyl sulfate, sodium lauryl 
sulfate, sulfonated vegetable oils (see Vegetable Oils, p. 37), sodium 
salt of an alkyl naphthalene sulfonic acid, and sodium lauryl! sulfate 
paste. 
Sodium monosulfonate of monobutyldiphenyl is a fine tan-colored 
powder readily soluble in water. It takes up moisture from the air, 
hence must be stored in a tight container in a dry place. A 40-percent 
aqueous solution is also available and is convenient to use. 
Sodium oleyl sulfate is a brown liquid, readily soluble in water. 
Sodium lauryl] sulfate is a white granular or flakelike material. It 
may also be obtained in a paste form. 
