(144) Wester, R. E., Cordner, H. B., and Massey, Jr., 
P. H. 1958, Nemagreen, a new lima, Amer. 
Veg. Growers 6: 31-32, 
(145) Whitehead, A. G, 1956, Plant parasitic nema- 
todes, Important pathogens in tropical agr- 
culture, East African Agr, Jour, 12: 92-96, 
(146) Williams, T,D, 1956, Theresistance of potatoes 
to root eelworm, Nematologica 1: 88-93, 
(147) Winstead, N. N., and Barham, W. S. 1957. 
Inheritance of resistance in tomato to root 
knot nematode, (Abstr,) Phytopathology 47: 
37-38, 
(148) Winstead, N, N,, and Riggs, R, D, 1963, Sta- 
bility of pathogenicity of B biotypes of the 
root-knot nematode Meloidogyne incognita on 
tomatoes, U,S, Agr, Res, Serv, Plant Dis, Rptr. 
47: 870-871, 
(149) Winstead, N, N., and Sasser, J, N, 1956, Re- 
action of cucumber varieties to five root-knot 
nematodes (Meloidogyne spp.) U.S, Agr, Res, 
Serv, Plant Dis, Rptr, 40: 272-275, 
PLANT RESISTANCE AS A MEANS OF CONTROLLING INSECTS 
AND REDUCING THEIR DAMAGE*+ 
Reginald H. Painter, Professor, Department 
of Entomology, Kansas State University, Manhattan 
Among various general means of injurious 
insect control, using intentionally selected 
resistant host plants differs from the other 
insect-control methods in at least three re- 
spects. The differences have both facilitated 
and retarded extensive use of plant resistance 
as a means of insect control. 
First, the entomologist attempting to de- 
velop insect-resistant plant varieties requires 
willing and enthusiastic assistance and co- 
operation of a plant breeder, who is cognizant 
of possibilities of this type of insect control 
and who will risk having his breeding plots 
damaged and results of his other experiments 
often badly distorted by insect infestation. 
The Kansas Agricultural Experiment Station 
has released to Kansas farmers from 1926 to 
date about 14 varieties representing 5 species 
of crops, each more resistant to 1 ofa total of 8 
different insects than competing varieties 
grown previously. This has been largely the 
result of 39 years of cooperation between 
entomologists and agronomists. 
Second, on the favorable side, the effect ofa 
resistant variety is cumulative and persistent, 
whereas that of an insecticide is sudden and 
decreasing in effectiveness until andunless re- 
applied. Successful use of a resistant variety 
often removes the resisted insect so that 
farmers, county agents, and even entomologists 
and agronomists become unfamiliar with it. 
This is in contrast to insecticides, where the 
chemical must be applied from one to many 
times a year and then repeated in later years, 
often in heavier dosages against an increased 
insect population, or in different formulation 
for populations that develop resistance to the 
first formulation. 
The continuous effect of control by use of a 
resistant variety contrasts with the sometimes 
cylic control attained by parasites and preda- 
tors, where there are periods of alternate 
abundance of injurious insects and their preda- 
tor and parasitic enemies. That does not mean 
that insecticides or parasites should not be 
used, but that resistant varieties give a dif- 
ferent kind of control. 
The third difference between resistant 
varieties and other control measures, espe- 
cially long-standing resistant varieties, is 
their treatment in textbooks of applied entomol- 
ogy. Information in most cases ranges from at 
best somewhat less than enthusiastic comment 
to statements that indicate gross misinforma- 
tion. Somewhat in defense of this situation is 
that textbooks cannot ordinarily be expected to 
be up to date even at time of publication, but 
ordinarily one expects information available in 
journals within the past 5 years to be in ad- 
vanced textbooks. There have been some ex- 
ceptions, such as the books by Wardel (1929) 
and Isely (1942). 

1 Contribution No, 882, Department of Entomology, Kansas Agricultural Experiment Station, Manhattan, 
138 
