8o 
Psyche 
[June-September 
In spite of the difficulties involved, Federal and some state authori- 
ties were still speaking in terms of “eradication” of the gypsy moth 
in 1956 and 1957, while other state and local people were by this 
time hesitant about backing an all-out eradication effort. 
In 1957, after about three and one-half million acres had been 
sprayed (two and one-half millions of them in New York State), 
DDT residues were found on forage crops and in the milk of cows 
that had grazed on treated areas in New York State, as well as in 
eggs from poultry farms that had received spray. 16 DDT tolerances 
for milk are set at zero by the Federal Food and Drug Administration 
and by health authorities in New York among other states. 
When the DDT residues were found persisting on forage crops 
and in the raw milk for periods up to a year, New York suspended 
eradication efforts “. . . so that,” as the USDA’s Cooperative Plant 
Pest Control Programs for 1958 put it, “the 1957 work could be 
fully evaluated and any required ‘mopping up’ could be done; how- 
ever, during the eradication season tests were made of several alternate 
insecticides more suitable than DDT for use on pasture and forage 
crops.” 
Since 1958, New York has been doing a greatly reduced amount 
of spraying by air, using in part the new insecticide sevin, a carbamate 
having very low toxicity to mammals and birds, and one leaving no 
residue in the milk. Unfortunately, sevin is not as good against the 
gypsy moth as is DDT, it is highly toxic to honeybees, and it injures 
plants to some extent. 
Aside from the dairy-linked residue problem, DDT has received 
rather good marks from most biologists checking the general ecological 
effects of mass spray at one pound to the acre. A few fish, are some- 
times killed, birds that catch insects on the wing depart, and certain 
aquatic insects suffer, but the known damage does seem tolerable. 
Long-term residual effects on soil organisms are, however, not well 
known. 
The chief short-range danger of mass aerial DDT campaigns lies 
with the loose spray practices or accidents that result in duplication 
(or worse) of spray strips in a given area. Field insect control men 
often complain about the quality of pilots available for some spray 
programs, and numerous incidents have occurred to illustrate the point 
that some of the pilots are irresponsible or incompetent, or that they 
are poorly directed. For this and other reasons, it seems certain that 
operational mass spraying does not always give the same safe results 
as are found for the neatly-sprayed test strips of some of the studies, 
and landowners are often justified in complaining of double or triple 
