-20- 
Squaflh . Heavy applications of 2-percent DDT dust at weakly inter- 
vals killed squash plants.— Underhill (349 ) ♦ 
Young squaoh and pumpkin plants were severely stunted and young 
cuoumber plants were stunted to some extent by a 3-percent DDT dust* 
The acorn squash was more susceptible than any of the other varieties. 
—Tate _et &!• (342 ) • 
A 10-percent DDT dust injured squash plants.— Haseman (203 ) • 
Wheat . Dosages as high as 0.2 percent by weight of technical DDT 
showed no injurious effects on the viability of seed wheat containing 
12 percent of moisture. The treated samples of wheat were examined 
once a month for 4 months*— Cotton et al. (120) . 
Effect of DDT on Fungi 
DDT at 3/4 pound per 100 gallons of water was not effective as a 
fungicide for early blight of potatoes.— Heuberger (207 ) . 
DDT is not a fungioide.— Horsfall (214 ). 
DDT SPRAY RESIDUES AND THEIR REMOVAL 
DDT toleranoe on foods 
A formal toleranoe of 7 mg. per kilogram for fluorine on apples and 
pears has been announoed. An informal tolerance of 7 mg. per kilogram 
for lead on apples and pears has been recognized for several years. "In 
view of the agreement among the toxioologists concerning the quantitative 
relationship of the toxicity of DDT to that of lead and fluorine, this 
iFood and Drug] Administration has conoluded that during the ooming 
year it will not be its purpose to inaugurate regulatory action against 
commodities containing 7 mg./kg. or less of DDT."— Dunbar (140 ) 
[l p.p.m. r 0.007 gr./lb. and conversely, 
0.01 gr./lb. = 1.42857 + p.p.m.] -RCR * 
Suggestions are presented on the use of DDT on various food crops 
so as to avoid a DDT residue of 7 p.p.m. or more.— Geigy Co. ( 174 ) . 
Residues on fruits and vegetables 
At Winchester, Va», Stayman Winesap apples that had received 5 
applications of DDT at the rate of 1 pound per 100 gallons of water 
(4 pounds of 25 percent DDT in third to seventh covers) bore a resi- 
due of 0.042 grain of DDT per pound. Washing with 1.3 peroent of hydro- 
ohlorio acid reduced the residue to 0.037 grain per pound; washing with 
