30 MASS. EXPERIMENT STATION BULLETIN 428 



10. Infestations of cranberry weevil, cranberry spittle insect, and lipwo.m 

 about normal. 



11. Honej'bees and bumblebees normally prevalent. 



Weather Studies. (H. J. Franklin.) Further studies since Bulletin 402 was 

 published in 1943 have produced additional material which has resulted in the 

 revision of the formulas for use in reckoning minimum bog temperatures with 

 the 7 p.m. weather data. 



Winterkilling. Cranberry winterkilling in Massachusetts in the winter of 

 1943-44 was the most extensive and severe in the memory of the oldest growers, 

 causing an estimated reduction in the 1944 crop of at least 30 percent. On many 

 bogs the vines were all killed down to the ground. The extent of this damage 

 was not surprising, for a much larger cranberry acreage than usual was not 

 flooded when it should have been because of the lack of enough rain to build up 

 water supplies in the fall and early winter. 



The severe frost of May 18-19, which cut off all the new growth that had 

 developed on the winterkilled bogs up to that time, and the severe drouth that 

 prevailed most of the summer were very unfavorable to good recovery of the 

 injured vines. In spite of this, the new vine growth by fall was satisfactory on 

 nearly all of the damaged areas. Some growers tried to help their bogs recover 

 by mowing off the dead vines, resanding, or fertilizing, but there is little evidence 

 that any of these measures was definitely beneficial. They had generally resulted 

 in an undesirable growth of runners. 



Frost. The frost on the night of May 18-19, 1944, considering the date of its 

 occurrence and the minimum bog temperatures reached (from 14° to 25° F.), 

 was one of the most severe in Massachusetts cranberry history. It killed all the 

 season's new cranberry growth on many bogs and caused the old cranberry 

 foliage on a few small areas to turn dark again as in winter. The extensive 

 injury from this frost was due partly to lack of water for flooding and partly to 

 freezing of the vines over the frost flood on some of the colder bogs. Also, since 

 most of the bogs were very dry and absorbed much more water than usual, many 

 did not get flooded as soon as they should have been. It was difficult to estimate 

 the damage to the 1944 crop because of the extensive injury from winterkilling. 



DEPARTMENT OF DAIRY INDUSTRY 

 J. H. Frandsen in Charge 



Sterilizing Agents for Dairy Use. (W. S. Mueller, J. E. Fuller, and E. Bennett.) 

 The search for new sterilizing agents which will be practical for dairy equipment 

 was continued during the past year. A sterilizing agent for dairy use should be 

 (1) highly germicidal in the presence of organic matter, (2) non-corrosive to 

 metals and rubber, (3) low in cost, and (4) non-toxic to humans. The germicidal 

 properties of 42 materials obtained from 14 manufacturers have been studied. 

 Where the manufacturer recommended the concentration to be used, the recom- 

 mendations were followed; otherwise, the material was used in 0.05 percent and 

 0.5 percent concentrations, and in some cases 1 percent was also used. The steri- 

 lizing properties of solutions of the different materials were determined by adding 

 1 ml. of raw milk to 99 ml. of the solution to be tested. After the milk had been 

 in contact with the solution for 5 minutes, proper dilutions were made and 1 ml. 

 quantities were plated according to the Standard Method for Milk Analysis 

 procedure. Out of the 42 materials, 15 were effective as sterilizing agents, 7 were 

 moderately effective, and 20 were ineffective. The classification of the materials 

 into groups and the germicidal properties of the various groups were as follows: 



