SQUASH BORER 
(Melittia satyriniformis Hbn.) 
Squash vines, in many sections of the country, may wilt suddenly 
early in the summer. Usually this wilting is due to the squash borer, 
a caterpillar which bores into the stem near the ground. Its presence 
may escape notice until piles of yellow, sawdustlike excrement, which 
falls from holes in the stem, become evident. 
Life History 
The adult is called a clear-winged moth because the hind wings 
are transparent, like those of a wasp. The female moth lays eggs on 
the stems in June or July in the North and in April and May in the 
South, or earlier in the far South. The minute young larvae, or 
caterpillars, on hatching from the eggs, bore into the stem, grow 
rather rapidly, and become full-grown when about 1 inch long, after 
a period of about 4 weeks. One generation occurs in the North, two 
in the South, and a partial second generation in intermediate regions. 
The winter is spent in the soil as mature larvae or as pupae. 
Injury 
When the borers are numerous they cause severe injury. They 
bore throughout the interior of the stems near the base and may 
travel up the stems, even to the petioles of the leaves. Sometimes 
vines are almost severed. The fruits are sometimes attacked. As 
the larvae become larger the excrement which is pushed out of holes 
in the stems becomes visible. While most serious on squashes, espe- 
cially the Hubbard, the borers also attack pumpkins, cucumbers, 
gourds, and other cucurbits. 
Control 
Although control is difficult, the following remedies have been 
recommended: Apply a dust mixture of derris or cube, diluted with 
talc, tobacco dust, or some other inert diluent. The mixture should 
contain not less than 1 percent of rotenone, which is a toxic constituent 
of derris and cube. Apply the dust to the stems and basal parts of 
the vines three or more times at 10-day intervals. The mixture may 
be purchased, or it may be prepared at home by mixing 8 pounds of 
diluent and 2 pounds of derris or cube containing 5 percent of rotenone 
(or 6 pounds of diluent and 2 pounds of derris or cube containing 4 
percent of rotenone). A spray composed of 1 part of 40-percent 
nicotine sulfate to 100 parts of water has been reported as effective in 
reducing infestations. Apply the spray to the stems near the base 
of the plant, and repeat the application at least weekly during the 
egg-laying period. 
The success of any insecticidal treatment will depend upon early 
and repeated treatment, because after the young larvae have reached 
the inside of the stem the insecticides will not affect them. 
The practice of covering the stems with soil to induce rooting 
beyond injured portions has long been followed with success, especially 
on heavy soils in humid areas. 
After the borers have entered the stems and their presence becomes 
evident, the only known remedy is to slit the stems longitudinally 
with a thin knife or razor blade and remove the borer. The injured 
portion should then be covered with soil. 
16— 207G2 
April 1941 U. S. Government Printing Office 
For sale by the Superintendent of Documents, Washington, D. C. — Price 5 cents 
