October, ’18] DAVIS: CO-OPERATION AMONG AGRICULTURISTS 
409 
lems to which it is related and can often continue it to a point nearing 
completion, varying according to the factors involved; but if the prob¬ 
lem touches directly or indirectly on any related branch of agriculture 
he should under all circumstances, for the sake of uniformity, usefulness 
and stability, consult with his colleagues in that particular related 
branch for corroboration and advice. We have attempted to plan 
our work along these lines with favorable results. In the Hessian fly 
program the work was planned in accordance with the needs of entomol¬ 
ogy but the agronomist was consulted on points dealing with fertil¬ 
izers, cultivation and the like for expert advice, and the practical and 
successful farmer similarly consulted for advice on the practical appli¬ 
cation of certain phases. In many of our investigations of farm crop 
pests, surveys have been made of one, two, or four square miles in 
infested districts, records being made of every possible factor which 
might be of importance in interpreting results, such as rotation, 
methods of cultivation and fertilization, possible barriers of timber or 
buildings, contour, meteorological influence and the like. These sur¬ 
veys have been mapped out and in the case of insects having a life 
cycle greater than one year, such as Lachnosterna, the records for the 
individual fields have been followed year after year, keeping even such 
detailed records as growth of vegetation on the ground at different 
seasons; for this little point is of much importance in considering sub¬ 
sequent infestations of white grubs if the observations are being made 
during a year when the parents of white grubs—the May-beetles—are 
abundant. A survey of this kind is of greatest importance in explain¬ 
ing the interrelations of the agricultural problems, and at the same time 
often shows by contrast just what conditions have affected one field 
in one way and an adjoining field differently, or have brought about 
an increase in insect pests in one and a decrease in another similarly 
located field. 
The above discussion is intended to emphasize the need of keeping 
closely in touch with workers in all branches of agriculture and to 
encourage freer exchange of ideas and plans between agronomists, 
entomologists, plant pathologists, chemists, foresters, animal husband¬ 
men, meteorologists and others. Likewise the agricultural investigator, 
and especially the entomologist, should not lose sight of the ecological 
applications for, as Doctor Forbes has said, the student in entomology 
should be required to complete certain courses in ecology as prerequi¬ 
sites to their courses in entomology, or at least ecology should be re¬ 
quired as a necessary part of entomological training. This likewise 
applies to the agricultural student. He is required to complete certain 
courses in agronomy, chemistry, farm mechanics, animal husbandry, 
entomology, etc., and here his requirements end. He becomes familiar 
