8 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 19 14 
beginning to appear, and no eggs of the gypsy moth had hatched. 
After the spray had dried, a fine crystalline deposit of DDT re- 
mained on all exposed parts of the forest. Observations indicated 
that the eggs hatched but that the small caterpillars were killed when 
they started crawling and came in contact with the DDT. No living 
larvae were found in the treated area. Furthermore, all black flies 
were eliminated from the area for at least a month after treatment. 
The success of this experiment offers promise for extending the 
period over which infested mens may be treated. The residual effect 
of DDT may permit the beginning of spraying a month or more be- 
fore gypsy moth eggs hatch. A study of small infested areas treated 
with DDT after foliage appeared and caterpillars were in different 
stages of development indicated that this insecticide also kills the 
larger larvae of the gypsy moth. 
The same aerial equipment was used for applying a concentrated 
cryolite suspension to infested woodland. A fine, uniform deposit of 
cryolite, which adhered well after considerable rainfall, was obtained. 
The final results of this treatment cannot be accurately determined 
until late summer when egg deposition is over. 
WAR FABRICS PROTECTED FROM TERMITE DAMAGE 
Owing to the rapid deterioration of untreated fabrics in the tropical 
theaters of war as the result of attack by termites and micro-organisms, 
tests were made during 1943, both in the laboratory and in the field, 
to determine which chemical treatments offered most resistance to dam- 
age by these destructive agents. Such tests were conducted in co- 
operation with the War Department and with several other agricul- 
tural agencies. About 900 samples of fabrics, consisting of such ma- 
terials as balloon cloth, canvas, twill, cotton Osnaburg, and light- and 
heavy-weight duck, were tested. A number of chemicals or mixtures 
were* found to protect the fabrics from damage by termites. 
PLANTATION INSECTS MAY INFLUENCE POSTWAR PLANTING PROGRAM 
Studies of insects affecting young trees planted in the reforestation 
program under way in the Lake States have shown that much can be 
done to reduce the probability of serious damage by insects by using 
certain mixtures of tree species in all forest plantations. In many 
cases insects have caused extensive damage in plantations that were 
established in blocks of single species. Where mixed plantings were 
made or the trees were planted among natural stands of hard woods, 
there has usually been less injury. 
One of the most important plantation insects in the Lake States is 
the spittle bug Aphrophora satatogensis (Fitch), heretofore unknown 
as a pest of pine. It is widely distributed, and many thousands of 
acres of plantations and young natural growth of jack pine and red 
pine show serious damage and in some eases considerable tree mor- 
tality from it. The life history and habits of the insect have been 
si ii< lied, and in the spring of 1944 arrangements were completed for a 
COOperal ive st udy with the Bureau of Plant Indus! ry. Soils, and Agri- 
cultural Engineering and Wisconsin State officials to determine the 
possibility of an interrelationship with some disease organism. The 
white pine weevil, the pine sawllies, the nine chafer, and the pine tor- 
toise scale are also important pests in tne extensive pine plantations 
