medicine, where treatment is increasingly 
by experts rather than by the patient himself 
or his family. 
The future is, as I have suggested, in re- 
garding control as a unified concept and thus 
in developing programs of integrated control, 
in which parasites and predators have a far 
larger role than now. I suggest that the future 
in the pest-control industry lies more in 
providing expert services to the public by 
applying integrated controls than in the sale 
of chemical pesticides alone. 
INSECT PATHOLOGY, PRESENT AND FUTURE 
A. M. Heimpel, Entomology Research Division, Agricultural Research Service, 
U.S, Department of Agriculture, Beltsville, Md. 
It was very appropriate that the title pro- 
posed for this presentation offered a forward 
view rather than a backward look at the field 
of insect pathology. To attempt to rewrite or 
improve on the reviews and articles of 
Steinhaus (1956, 1963, 1964), of Poltev (1963), 
and of Franz (1961) would be to gild the lily. 
Suffice it to remind you that entomologists in 
North America have been intrigued by the 
occurrence of disease in insect populations 
from the beginning. Natural disease epizootics 
are very impressive when they affect an insect 
under study. As a matter of fact, they can 
put an insect ecologist out of work for a whole 
season or longer. Consequently, observations 
of insect disease are scattered throughout the 
earlier literature. 
Contributions by White, Glaser, and others 
stimulated early interest that culminated in 
the establishment of a laboratory of insect 
pathology under E, A. Steinhaus at the Uni- 
versity of California in 1945. In 1946, the 
Canadian Department of Agriculture set up a 
superb laboratory for basic research ininsect 
pathology in Sault Ste. Marie, Ontario, Canada. 
Since then, many fine laboratories committed 
to this field have been built all over the 
world, and a recent compilation of investi- 
gators interested in insect pathology lists 
more than 400 names. 
The emphasis placed on basic research in 
insect pathology by most of these new labora- 
tories has been most rewarding. In the last 
20 years, enormous strides have been made 
and a large amount of knowledge has been 
accumulated concerning several groups of 
micro-organisms that have great potential 
for insect control. Several men, such as 
70 
E, A, Steinhaus, J. J. DeGryse, E. F, Knipling, 
P, Grison, K. Aizawa, and J. Franz, are 
responsible for encouraging, and sometimes 
insisting upon, the basic research necessary 
to understand the principles of microbial 
control. Thus, it is that insect pathology has 
developed recently with an excellent balance 
maintained between the basic and the applied 
research. The wisdom of this approach, as 
reflected in the confidence that insect pathol- 
ogists have in the use of microbes to control 
some of our insect pests, is now a Certainty. 
The study of insect micro-organisms has 
been somewhat biased. For example, study of 
the protozoa that infect insects has been 
until recently a rather neglected field. Such 
neglect might be due to the difficulty in 
propagating these fastidious organisms or it 
might be that the protozoa, as a rule, do not 
create sensational mass epizootics, They do, 
however, exert enormous pressures on insect 
populations by retarding larval development 
in the field and thus expose the target insects 
to natural enemies longer; and they also re- 
duce the fecundity. These organisms might 
well be used for long-term, integrated control 
agents against insects affecting forests, in 
which time would be of less importance than 
in field crop protection. Other protozoa, such 
as some of the schizogregarines, are highly 
virulent and might be used to great advantage 
in normal control actions. The works of 
several scientists are worth studying in con- 
nection with these fascinating organisms. 
They are J. Weiser of Czechoslovakia, 
John Paul Kramer and R, E, McLaughlin of 
the United States, J. Lipa of Poland, and 
Elizabeth U. Canning of England. 
