INSECT ENEMIES OF EASTERN FORESTS St 
Mites 
One of the simplest means for controlling spider mites is to wash 
the plants several times with a stream of water under considerable 
pressure. Infestations on ornamentals and nursery stock can usually 
be kept down by this method. A derris spray with sulfonated castor 
oil (turkey red oil) as a spreading agent has been found ver y effective 
when used in the following propor tions: 
For For 
Materials: large quantities small quantities 
Derris powder (4 percent rotenone)______ 1 pound 14 ounce, 
Sultonated’ castor ole S22 or ss ee 1 quart 1 ounce. 
\IYCT HS a Sa oa yn ee 100 gallons 3 gallons. 
First add the oil to the water; then with a small amount of this mix- 
ture make a paste of the powder and stir it into the rest of the oil and 
water. 
Derris and other rotenone insecticides are comparatively non- 
poisonous to man and other warm-blooded animals, although they 
do irritate the tender skin and mucous membranes. 
The summer white oils (p. 54, formula 10) give good control of 
both the mites and the eggs. They may cause injury to spruce, but 
can be used safely on pine and juniper, as well as on most broad-leaved 
species. 
Sprays made of glue or billposter’s paste have been reported as 
giving good control, especially on conifers. Use 1 pound of cabinet- 
maker's glue in 10 gallons of water, dissolving the glue in a small 
amount of warm water and straining it before adding it to the full 
quantity. Buillposter’s paste is used at 1 pound to 25 oallons of water, 
preferably with a wetting agent added. If some of the tips stick 
together, this can be remedied by an application of water. 
Several new chemicals, such as tetraethyl pyrophosphate and para- 
thion, now being developed by private industry, are proving to be 
exceedingly effective for the control of spider mites. 
Dusting sulfur or the wettable sulfurs are also effective against 
spider mites, especially when temperatures are above 80° F. When 
temperatures are extremely high there may be some danger of injur- 
ing tender foliage with the sulfur materials. 
It is usually necessary to make two or more applications, a week or 
10 days apart, with such materials as derris or sulfur. The other 
materials should not be applied so frequently. 
INSECTS ATTACKING FOREST PRODUCTS 
Insect damage to such forest products as logs, green or seasoned 
lumber, posts, “poles, or lumber and furniture in “buildings can be 
classed in two br oad groups: (1) Defects caused in the wood of living 
trees, and (2) injury caused to wood after the tree is felled. The 
former damage occurs in the forest and is difficult to control, whereas 
the latter, involving materials and finished articles of a much higher 
value than that of the standing tree, may be justifiably handled by 
much more expensive and more elaborate methods of control. 
Theoretically speaking, there is little excuse for the enormous bill 
annually paid as the result of insect attack on forest products. Con- 
ditions occasionally arise, however, over which man has little or no 
