30 MASS. EXPERIMETN STATION BULLETIN 441 



and less expensive than the previously recommended control of asters with ferrous 

 sulfate. 



3. Paradichlorobenzene, scattered at 7J^ pounds per square rod and covered 

 immediately with an inch of sand, has previously been recommended for con- 

 trolling poison ivy, chokeberry, loosestrife, and white violets. Experiments now 

 show this treatment to be effective against wild bean (Apios) and three-square 

 grass (Scirpus), and occasionally against the small bramble (Rubus). In addi- 

 tion, this treatment was found effective against poison iv}^ and wild bean when 

 applied early in April while ivy' and bean were still dormant. 



4. Ferrous sulfate can be spread at the rate of 50 pounds per square rod with- 

 out injuring cranberry vines. This heavy application, made in June, July, or 

 August, killed all white violets, asters, and needle grass. However, serious injury 

 to cranberry vines resulted when this treatment was applied to bogs sanded 

 within a year. Tender cranberry roots near the surface in the new sand were 

 apparently severely burned. 



Some study and experimental work has been done toward protecting cranberry 

 bogs from winterkilling and frost by means other than flooding. This work looks 

 promising but is still in its preliminary stages and will not be described more 

 fully now. 



Cranberry Breeding. (F. B. Chandler, Collaborator; H. F. Bergman, U.S.D.A.) 

 One hundred and fourteen selections from the 10,685 cranberry seedlings produced 

 by the U.S.D.A. have been set in Massachusetts for further testing: some in four 

 bogs, and the others in two or three bogs. From these selections, it is hoped that 

 some new varieties will be developed which will be resistant to false blossom and 

 fungous diseases and will give good j'ields of desirable fruit. 



The -results of the breeding work and some of the information about these 

 selections were published in Cranberries for May and June, 1947. 



Fertilizer Requirements of Cranberry Plants. (F. B. Chandler and Wm. G. 

 Colby.) Plots have been laid out and fertilizer applied to study nitrate vs. 

 ammonia as a source of nitrogen for cranberries. The rate of application of 

 nitrcgen in the treated plots has varied from 10 to 80 pounds per acre. Fertilizer 

 applications are being made before bloom (June), before fruit-bud formation 

 (late July), late in the fall, and early in the spring. These plots have not been 

 established long enough to give information on yield, but vines on fertilized plots 

 have much better vigor and bloom and are much heavier than vines on unferti- 

 lized plots on both hard-bottom and peat-bottom bogs. 



DEPARTMENT OF DAIRY INDUSTRY 

 H. G. Lindquist in Charge 



Sanitizing Agents for Dairy Use, (W. S. Mueller.) Since the last war many 

 new sanitizing products are available for dairy use. In general these new prod- 

 ucts, both liquids and powders, have in common a quaternary ammonium salt 

 of one fcrm or another, which is the active bactericidal material. The effective- 

 ness of these new sanitizing agents for dairy use is being investigated and the 

 following progress has been made: 



1. Bactericidal Properties of Some Surface- Active Agents. (W. S. Mueller 

 with the cooperation of Emmett Bennett of the Chemistry Department and J. E. 

 Fuller of the Bacteriology Department.) Results of this study were published 

 in the Journal of Dairy Science 29, November 1946. It was concluded that out 



