infested soils, require reevaluation of our 
fertilizer, seeding, irrigation, and manage- 
ment practices before our farmland can reach 
its full potential, 
Plant-parasitic nematodes occur in most 
soils, They may become a severe problem 
when the land is intensively cultivated, Un- 
fortunately modern farming practices, which 
require frequent, intensive production of a 
limited number of crops, favor the rapid 
increase of these pests, Although good soil 
and crop management practices usually reduce 
nematode damage, the best practices designed 
for nematode control often are not economical; 
or they are not entirely successful or prac- 
tical for controlling all types of parasitic 
nematodes, Under these circumstances, the 
use of nematocides provides the best prac- 
tical means of controlling many nematodes, 
USE OF NEMATOCIDES 
Nematocides are used, at least to a limited 
extent, in the production of crops in every 
section of the country, The importance of 
controlling nematodes on tobacco was realized 
many years ago, and, in 1964, about 75 per- 
cent of our total tobacco acreage was treated 
with nematocides to control root-knot and 
other nematodes, Hundreds of acres of sugar- 
beets are grown each year on land chemically 
treated to control the sugarbeet nematode, 
Soil fumigation has been an accepted practice 
in the production of pineapples in Hawaii for 
several decades, Recently many growers in 
Puerto Rico have begun to recognize the need 
for control on pineapples and other crops, 
Cotton farmers in both the Western and 
Southern States are obtaining higher cotton 
yields at reduced unit-production cost by using 
nematocides, In the Southeastern United States 
nematocides are being used to control several 
species of nematodes attacking peanuts, Within 
the past few years, growers have increased 
their efforts to reduce nematode losses on 
vegetables, melons, strawberries, grapes, 
citrus, peaches, and cherries by using 
nematocides, Chemical control has become 
increasingly important in forest, fruit, nut, 
and ornamental nurseries throughout the United 
States, An interesting new development is the 
53 
use of postplanting nematocide treatments for 
partial rehabilitation of nematode-damaged 
shrubs, trees, and turf grasses, for bothhome 
and commercial establishments, However, at 
present this type of treatment is used only 
on a small scale, 
In the United States nematocides are being 
used on about 1 million acres of farmland 
each year, with sales approximating $25 mil- 
lion, Consumer demand for nematocides often 
exceeds local supplies. The use of nemato- 
cides will probably double within the next 
few years as greater production demands are 
placed on our farmlands for food and fiber, 
With the advent of cheaper and more effec- 
tive means of applying nematocides on large 
acreage and on moderate acre-value crops, 
such as corn, cotton, soybeans, peanuts, 
Sugarcane, and forage crops, vastly expanded 
markets will open, Increased use of nemato- 
cides will be necessary because of (1) the 
trend toward specialized use of land on which 
crop rotations are not considered practical; 
(2) increased farm capitalization that re- 
quires maximum production, which is im- 
possible without nematode control; (3) greater 
use of marginal soils, which are frequently 
sandy and located in warmer areas of the 
world where conditions are ideal for nema- 
tode reproduction and damage; and (4) natural 
biological adaptations of nematodes that will 
increase their ability to parasitize and de- 
stroy crop plants, 
PROPRIETARY NEMATOCIDES 
About 20 chemicals and combinations of 
nematocidal chemicals are manufactured, 
Many more will be available within the next 
few years, Those most common and widely 
used at the present time are volatile, have 
a fumigating action in the soil, and are re- 
ferred to as soil fumigants, Some newer 
nematocides have low volatility and do not 
diffuse in the soil to any appreciable extent; 
therefore, dispersal of such chemicals re- 
quires good soil incorporation; or they must 
be moved through the soil by either rainfall 
or irrigation, Often nematocides are soil 
disinfestants, and in addition to controlling 
nematodes they kill soil insects, fungi, and 
weeds (12), 
