Most foliar and fruit diseases of orchard crops can be controlled satisfactorily by 
the use of currently available fungicides. Attractive fruit of high quality is available to 
the American housewife because of the availability and use of newer organic fungicides, 
both before and after harvest. 
The devastating damages due to late blight of potatoes and tomatoes can be averted 
by skillful use of modern fungicides. Beginning about 1945, the use of a combination of 
ethylene bisdithio carbamates and DDT as analmost standard spray contributed markedly 
to doubling the yields of potatoes in the United States between 1939 and 1952 (1). 
Fungicides are available to reduce markedly the damage caused by lima bean downy 
mildew, bunt, and dwarf bunt of wheat, onion smut, and blue mold of tobacco. A newer 
approach of plant disease control has evolved. This makes use of synthetic therapeutants 
in addition to antibiotics which permeate the host, then kill or suppress the pathogen, 
and thus prevent disease development even after infection has occi..red. Organic and 
inorganic nickel compounds are under intensive study which show good promise as 
eradicant and protectant treatments for the cereal rusts. 
The essentiality of crop-protecting chemicals in modern American farming cannot 
be questioned with any scientific justification. Enough specific data are not available to 
determine the total economic benefits that result from present uses of these chemicals, 
but undoubtedly marked reductions are being made in production costs wherever these 
materials are being used. In addition, improved quality and yields, lower labor cost, 
less risks of crop failure, and other benefits are being realized as improved pesticides 
are safely put to use. 
PROBLEMS 
Progress in the synthesis, evaluation, development, and use of pesticides is attrib- 
utable to the research emphasis by public and private agencies. The research effort is 
far from adequate for unsolved and partly solved pest problems. To exploit adequately 
the potentials of synthetic organic chemicals for combatting plant disease organisms, 
weeds, and nematodes more efficiently, and without fear of harm to crop plants and to 
men and animals that eat them, there must be a marked increase in the number and sup- 
port of scientists to do the necessary work. 
In spite of the progress in the use of pesticides, farmers still endure an estimated 
loss of over 7 percent of crop productivity from plant diseases (5) and weeds cost the 
Nation’s agriculture at least 10 to 15 percent of the productivity of all crop and grazing 
lands. In addition, weeds cost nonagricultural enterprises an estimated $1 billion an- 
nually. Data are incomplete for accurate estimates but nematodes are known to cause 
damages in excess of $300 million annually and in disease complexes with fungi they 
cause even greater losses. Sizeable losses in the quality of food and feed crops occur 
due to unregulated maturation and sprouting. The losses in yield due to premature drop 
of fruits or shattering of seed and frost damage indicate the real and potential losses 
that might be averted by the use of improved growth regulators. 
There is still a critical need for improved economical chemicals to cope with many 
problems posed by various agricultural pests. This need can be fulfilled by expanding 
research to provide more knowledge so that we can design molecules for specific pur- 
poses and by utilizing more fully our present knowledge regarding the relations between 
molecular configuration and biological activity. New materials and techniques to control 
pests and modify plants must be continually sought by imaginative scientists so thata 
massive assault can be made on the problems along a broad front. 
The following illustrate some of the critical. unsolved problems which require more 
effective and cheaper chemicals and practices for their solution: 
Weeds--No effective, economical weed control methods are available for annual 
broadleaved and grass weeds in soybeans, most vegetables, orchard crops, peanuts, and 
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