SECTION II--PROGRESS AND PROBLEMS 
USE OF HERBICIDES GROWTH REGULATORS, NEMATOCIDES, AND FUNGICIDES 
W. B. Ennis, Jr.} 
INTRODUCTION 
Remarkable progress was made during the last two decades in developing and in 
using herbicides, growth regulators, nematocides, and fungicides to improve the effi- 
ciency of agricultural production. The decreasing labor supply and the steadily increasing 
necessity for mechanization of agriculture require more and more chemicalization of 
agricultural production. The progress made, the materials and ‘‘know-how”’ available, and 
the continuing search for new and improved chemicals give us every right to believe that 
concentrated basic research will give more effective and safe practical methods of com- 
batting weeds, plant disease organisms, nematodes, and other problems including the 
regulation of plant growth. 
This paper deals primarily with highlights of early and recent progress in using cer- 
tain noninsecticidal chemicals to solve major pest problems in American agriculture, and 
presents examples of unsolved problems which require cooperative basic research for 
solution. Lines of research are outlined, which require increased scientific manpower and 
support, if the development and safe use of noninsecticidal chemicals are to keep pace 
with agricultural needs. 
EARLY PROGRESS 
Fungicides--Fungicides were used earlier than herbicides, nematocides, and growth 
regulators. As early as 1,000 B. C., Homer spoke of ‘‘the pest-averting sulfur’’ (5), and 
as early as 1705 mercuric chloride was recommended as a wood preservative (3). In 
ae copper sulfate was used with variable results for the control of bunt on wheat seed 
5). 
The modern era of fungicide research dates from Millardet’s discovery of Bordeaux 
mixture in the vineyards of France during the severe epiphytotic of downy mildew of 
grape in the 1880’s (3). For thenext 75 years it was used increasingly and was a frontline 
defense against the ravages of the late blight fungus of potatoes. Up to about 1930 Bor- 
deaux mixture, lime-sulfur solution, and self-boiled lime -sulfur were the standard control 
fungicides (2). 
Introduction of organic mercury compounds for seed treatments in 1915 (4) provided 
a means of breaking the pernicious transmission of plant pathogens from one crop to 
another by way of seeds. 
1Chief, Crops Protection Research Branch, Crops Research Division, Agricultural Research Service, U. S. Department of 
Agriculture, 
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