I believe we will continue to find satisfac- 
tory solutions to many of our problems in 
future years by breeding crops and animals 
that resist attack by some of their most 
destructive pests. 
In addition to plant and animal breeding, 
other biological methods for controlling pests 
are among our most important approaches, 
although not at the moment among our most 
extensive practices, The activities of biologi- 
cal control organisms in nature are extremely 
beneficial. But, when these organisms are used 
for specific control purposes, they often are 
not adequate to meet the standards of agri- 
cultural production efficiency our modern 
economy requires. 
Yet we know that their use in the years 
ahead will likely increase substantially... 
and their development remains only to be 
fully explored and exploited. These natural 
control techniques include natural enemies of 
insects and weeds, such as parasites and 
predators; pathogens, such as bacteria, fungi, 
protozoa, and viruses; alteration of genetic 
characteristics of the pest; and preventing 
seed or pollen production of the unwanted plant. 
The potential use of one organism tocontrol 
another is unusually promising. We already 
have several such organisms for afew pests-- 
the milky spore disease tocontrol the Japanese 
beetle; the Bacillus thuringiensis, which con- 
trols severalinsects. These organisms--which 
can be applied directly to crops in the same 
way as insecticides--appear to be specific in 
their action, and they do not impair the work 
of parasites and predators. 
We are continually finding new insect patho- 
gens, And we are making excellent progress 
in developing techniques for the mass produc- 
tion of specific organisms for practical use. 
Only recently we found two virulent protozoan 
organisms that may provide a safe and effec- 
tive way to control the boll weevil--a pest we 
have been investigating for over 60 years. 
Just as insects are attacked by other orga- 
nisms, they in turn can be used to eliminate 
other insects and unwanted plants. The U.S. 
Department of Agriculture has brought in about 
650 natural enemies of insects and weeds since 
1888, and about 100 of them have become 
established. Perhaps the best example is the 
use of beetles to control Klamath weed, a 
destructive pest in the western part of the 
62 
United States. I am told that 2 million acres 
of this weed were destroyed by this unusual 
method. We are continuing the worldwide 
search for these parasites and predators and 
believe they will always be an essential part 
of our pest-control practices. 
Cultural and management practices that 
reduce the necessity for pesticides have long 
been successful and are constantly being im- 
proved. Such practices as crop rotation, bal- 
anced fertilization, plowing under and burning 
stubble, destruction of insect breeding places, 
and adjustment of planting and harvesting dates 
to minimize pest damage all have their place 
in controlling pests. Sanitation practices and 
management systems to break the life cycles 
of internal parasites keep some livestock 
diseases in check without pesticides. 
So, aS you see, we have a large arsenal 
of weapons at our disposal, and many of them 
can be combined in various ways to doan even 
more effective job. But we do face some 
rather formidable obstacles in developing 
these measures to their fullest possible poten- 
tial. May I cite a few of these obstacles. 
First, we simply don't know enough about 
the pests we are dealing with and trying to 
control, whether by chemical or nonchemical 
means, Their life cycles, physiology, ecology, 
genetics, and growth habits are still largely 
mysteries that we are just beginning to unravel 
through strong basic research. 
This information is important in developing 
chemical means of pest control. It is abso- 
lutely essential if we are to supplement chem- 
ical control with biological means. We are 
attempting to control weeds and insects for 
example, whose life cycles are completely 
unknown. We don't know for certain whether 
some weeds are perennials or annuals. Such 
knowledge is essential if we are to develop the 
best means of eliminating these pests. 
Second, we cannot predict with any cer- 

tainty the effects of various kinds of treat- 
ment on the pests we are trying tocontrol... 
or on the other organisms in the environ- 
ment. This is equally true of biological ma- 
terials as well as chemicals. This results 
from inadequate research on the pests them- 
selves and forces us to use "trial and error" 
methods in using pesticides, rather than 
methods based on knowledge of the pests 
and their life processes. 
