ANNUAL REPORT, 1944-45 33 



ber of square feet allowed per bird in the pen. The electric ventilation system 

 was rebuilt so as to use a smaller duct, and the outlet from the duct increased 

 in size to reduce drafts across the floor. The main features of circulating a rela- 

 tively large volume of air across the floor and the introduction of a small amount 

 of fresh air were retained. Windows were kept closed throughout the season, the 

 sole intake of air being through a 6" pipe in a pen housing 100 birds. Tempera- 

 tures were kept higher than would have been possible in this uninsulated house 

 with slot or window ventilation. Litter remained good. 



In another pen, slot ventilators were baffled, which permitted placing roosts 

 and elevated feed hoppers well toward the front of the house without fear of 

 drafts. The new arrangement permitted increasing the number of birds until 

 only 3 square feet of floor space per bird was allowed in place of the conventional 

 4 square feet. This was accomplished without sacrificing the health of the birds 

 or loss of egg production. 



Hay Drying. (C. I. Gunness, J. G. Archibald, C. H. Parsons.) Equipment was 

 installed in one of the college barns in 1944 for curing hay partially cured in the 

 field. A sj'stem of ducts was installed on the barn floor and air blown into these 

 ducts, the air being forced up through the partially cured hay. About 40 tons 

 of hay were cured, the greater portion of which was put into the barn with a 

 moisture content of 45 percent. The hay was cured satisfactorily and indications 

 are that this system can be used in New England with considerable success. 



The trial is continued during the current season and another installation has 

 been made for curing baled hay. 



DEPARTMENT OF ENTOMOLOGY 

 Charles P. Alexander in Charge 



Investigation of Materials which Promise Value in Insect Control. (A. I. 



Bourne and W. D. Whitcomb.) Work in connection with the cooperative project 

 with the Dow Chemical Company was continued, both at Amherst and Waltham. 



Tests in different blocks of the college orchard and in nearby commercial 

 orchards supported previous results and showed that DN-111 or D-4 properly 

 applied were dependable to a very high degree in subduing summer outbreaks of 

 European red mite. In one of the experimental blocks in which tests were being 

 made of DDT as a replacement of lead arsenate, red mite apparently suffered no 

 inconvenience from repeated applications of DDT and by early July had in- 

 creased to an average of 175 mites per leaf. DN-111 in one application reduced 

 the population to an average of 1.5 mites per leaf within 24 hours, and no serious 

 later build-up took place. 



DN-111 and D-4 applied to beach plums heavily infested with red mite re- 

 duced the mites almost to the point of extinction. 



In several commercial orchards the owner applied DN-111 following standard 

 directions and secured as satisfactory control as in our own test blocks. This 

 supported our contention that, if the material is thoroughly applied (trees 

 sprayed from the ground), DN-111 can be expected to give a high degree of con- 

 trol, and that D-4 dust will give practically as good results if sufficient time is 

 taken to insure thorough coverage. 



Trees of Wealthy, Cortland, and Baldwin varieties were given 5 applications 

 of DN-111 plus wettable sulfur plus lead arsenate between May 20 and August 11. 

 No injury- was noted on any variety. The season of 1944 was not of a type to 

 induce spray burn of any type so that while these tests are encouraging they need 

 to be supported by further work in a more normal year. 



