ANNUAL REPORT, 1944-45 61 



of the trees sprayed in 1944 tailed to blossom at all. Two or three that had re- 

 ceived the heavier sprays had a light bloom, but the sprays were not generally 

 successful in causing annual cropping. 



Experiments in 1945 were interfered with by the freeze of April 23. Naphtha- 

 lene acetic acid sprays applied at concentrations of 10, 20, and 30 p. p.m. appar- 

 ently reduced set in all cases. Effectiveness seemed to depend more on variety 

 than on concentration. Wealthy and Baldwin were thinned less than Melba and 

 Early Mcintosh. Spur leaves seemed to show some dwarfing injury and this also 

 seemed to depend more on variety than on concentration, Melba showing the 

 most injury. This limited experience gives some hope that this material has 

 value as a blossom thinning spray. 



Killing Poison Ivy. (L. Southwick.) Following two yearly applications of 

 ammonium sulfamate to poison ivy under apple trees, there is only slight indica- 

 tion of recovery (July 1). If the ivy makes anj- growth the year following treat- 

 ment, experience seems to show that it will continue to grow and spread. In 

 short, treatment is needed until there is no recovery. Probably one pound of 

 the chemical per gallon of water is best. Other promising materials are now being 

 developed and further experimental tests are under way. 



Chemical Control of Weed Grasses. (L. Southwick.) In the effort to subdue 

 grass growth around the bases of young apple trees in sod, an application of am- 

 monium sulfamate was made on a quiet, hot, humid day in August 1944, to an 

 area about 5-6 feet in diameter. One pound of chemical was used in one gallon 

 of water and a small amount of a special wetting agent was included. A fairh- 

 drenching application was made. The grass was killed and showed very little 

 recovery up to July 1, 1945. Apparently no injury to the trees resulted even 

 though the spray got on the trunk bark. This method may prove to be a good 

 substitute for cultivation or hand hoeing around young trees. 



A similar test of this material in May 1945 on the sod strip along a row of 

 blueberries resulted in severe damage to the bearing blueberry bushes. Within 

 2 or 3 days the foliage began to take on a reddish hue and it now appears that 

 the bushes may be killed. Probably the shallowness of the blueberry root system 

 was a factor. This experience shows the necessity for careful testing before toxic 

 chemicals are used in the commercial or home fruit planting. 



Further work on weed and grass control is under way with several promising 

 materials. 



DEPARTMENT OF POULTRY HUSBANDRY 

 F. P. Jeffrey in Charge 



Broodiness in Poultry. (F. A. Hays.) The major objective is to develop a line 

 of Rhode Island Reds that never exhibits the broody instinct. The mode of 

 inheritance of broodiness is rather well understood, but there are several obstacles 

 yet to be overcome. The majority of the females that carry a broody inheritance 

 exhibit the instinct in the first laying year; yet there are some individuals that 

 fail to display broody behavior even in two or three years of laying that will, if 

 retained longer, become broody. Degree of broodiness is governed by inherited 

 factors. The problem of testing for deferred broodiness and of breed-testing 

 all males is the chief concern at present. 



The generation hatched in 1941 consisted of 55 females, one of which exhibited 

 broodiness in the first laying year. The generation hatched in 1942 (106 females) 

 exhibited no broodiness the first year. The generation hatched in 1943, made up 



