ANNUM. REPORT, 1940 59 



in the other two houses; and in the house provided with soil cable, the 

 htter was drier than that in the insulated house. At the end of the trial 

 the moisture in the litter in tlie uninsulated house was 48 percent, in the 

 insulated house 37 percent, and in the house equipped with soil cable, 30 

 percent. Chick growth and feathering were practically identical in the 

 three houses. 



More electric current was used for the soil calile tlian was considered 

 practical. 



Tiie worI< will be repeated during the coming season and an effort will 

 be made to reduce the current consumption ])y rearrangement of tlie 

 heating calile and reduction of tlie heating time. 



DEPARTMENT OF ENTOMOLOGY 

 Charles P. Alexander in Charge 



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



1. Bourne.) 



Oil Sprays for Dornnvit Applications. (A. I. Bourne.) The close of the 

 winter season was marked by much cold weather and snowfall consid- 

 erably in excess of normal during March, while April was so unseasonably 

 cold and wet that orchard and shade trees remained dormant throughout 

 most of the month and seasonal development was very slow until May. 

 Snowfall of 2.5 inches on April 12 and 13 and 4 inches on the 21st and 

 22d with accompanying low temperatures combined to hold tlie trees 

 dormant but furnished very unfavorable conditions in the orchards for 

 dormant applications of DN oils and similar sprays. It was difHcult to 

 operate spray equipment under such conditions, and the snow and low 

 temperatures after applications of oils increased the danger of injury to 

 sprayed trees. 



The cooperative project with the Dow Chemical Company on a study 

 of the value of DN sprays involved the use of dififerent concentrations of 

 dinitro-ortho-cyclo-hexylphenol (DNOCHP) powders dissolved in vary- 

 ing strengths of a commercial oil emulsion. Similar studies were made 

 of dinitro-orthocresol (DNOC) and dinitro-phenol (DN-Phenol) com- 

 pounds. These mixtures were tested in the college orchard for their 

 effectiveness against overwintering eggs of European red mite and or- 

 chard plant lice. The infestation of European red mite in tiie experi- 

 mental blocks was negligible, and the number of overwintering eggs of 

 aphids was very much smaller than in 1939. The sprays were applied 

 April 11 while the trees were in strictly dormant condition. Although 

 there was a fall of 2.5 inches of snow the following day and an accom- 

 panying drop in temperature to 20° P., no injury resulted nor was any 

 retardation in bud development noted. The DNOCHP-oil emulsion and 

 DNOC-oil emulsion sprays gave practically perfect kill of aphid eggs. Un- 

 sprayed checks showed an average of 530 lice per 100 clusters on Baldwin 

 and 890 per 100 clusters on Mcintosh trees. On sprayed trees the number 

 of lice was seldom greater than 1 per 100 clusters. The DN-Phenol 

 combinations were noticeably less effective but gave good commercial 

 control. 



Solutions of y., 3/4, and 1 percent of DNOCHP in oils of 52, 87, and 

 108 sec. Saybolt viscosity, applied while tiie plants were in strictly 



