1. Science now provides man with weapons and strategy and is making 
these increasingly effective. Weapons against agricultural pests include 
pest-killing chemicals; serums, antibiotics, vaccines, and other biologicals 
for fighting animal diseases; and new plant varieties bred for resistance 
to specific pests. Strategy for pest fighting includes organized efforts to 
use research weapons and regulatory work of inspection and quarantine, 
Our twentieth century has been called the first time that man has been 
able to fight back aggressively against plant and animal pests. 
2. Meanwhile, the volume and speed of modern transportation have 
enabled stowaway agricultural pests to rove the world, as never before, 
Thus both man and pests have gained advantages. As the contest 
stands, they are about evenly matched, This represents a gain for man's 
side, because in all earlier ages he was practically helpless against pest 
outbreaks. 
The United States Puts Prevention First 
The United States builds its protective system against agricultural 
pests on three firmly held principles: 
1, It is better and cheaper to keep out plant and animal pests and 
diseases than to have to fight those that get in. Prevention is 
always the preferred line of action, 
2. If pests get in, it is better and cheaper to eradicate them than to 
live with them. 
3. When pests cannot be wiped out by practical means, then the third 
and last line of action is to set up controls, to minimize damage, 
Past Experiences Show that Prevention Pays 
Records of a few of the foreign plant pests that have brought trouble 
and loss to people in the United States are summarized in table 1, These 
case histories, and others that could be mentioned, show that small inci- 
dents are enough to give plant diseases and insects a destructive foothold, 
TABLE 1.--Some foreign plant pests that have invaded the United States 
When and where 
first found in Arrived from 
continental U.S. 
Name and nature 
Small start. . .serious consequences 
of pest 
Stem rust fun- 
gus--bred on 
barberry bushes, 
spores spread 
and destroy 
grain 
Before 1726; 
New England 
Europe Early colonists brought barberry with them as a 
pretty redberried bush. Some bushes were in- 
fected with stem rust fungus. By 1726, barberry 
was blamed vaguely, but rightly, for "blasted" 
grain, and landowners were told: destroy bar- 
berry or be fined. But barberry was still ad- 
mired, and taken westward in the 1860's, to run 
wild. One stem rust epidemic ruined 200 million 
bushels of wheat and precipitated wheatless days 
for civilians in World War I. Currently, 19 
grain-growing States are working with the U. S. 
Department of Agriculture to eradicate barberry, 
and are destroying more than 3 million bushes a 
year. 
