70 MASS. EXPERIMENT STATION BULLETIN 402 



In an unusually early season such as that of 1929, both varieties, of course, 

 ripen earlier, but this makes little difference in the relative temperatures to which 

 they are subjected. For example, a simple summation of "day degrees" from 

 September 1 to October 15 is 1265 and from September 21 to November 20, 1137. 

 The corresponding indexes are 97.19 and 92.10. 



There is, usually, a decided difference in the rot fungi which are most active 

 during these two periods. Temperature studies of the growth of these fungi in 

 culture show that the early rot fungi, such as Acanthorhynchus vaccinii, Glomerella 

 rufomaculans, and Guignardia vaccinii, grow very little below 50° P., the mean 

 temperature usually reached in the Boston region about October 22. During 

 the entire period, then, of the storage of the Early Blacks, they are subjected to 

 the attacks of early rot fungi. The Howes, on the other hand, during the portion 

 of the storage period after November 1, are for practical purposes exposed only 

 to the attack of the end rot fungus, which is able to grow somewhat even at 32° 

 and whose optimum temperature is about 68°. It is evident, then, and must be 

 kept in mind continually in discussing keeping quality in any of its relations that 

 even in Massachusetts the term means something very different for different 

 varieties. 



Variation in the Keeping Quality of the Cranberry Crop as a Whole 



One of the observations most frequently made by those who have had long 

 experience in growing and handling cranberries is the variation in keeping quality 

 of the crop from year to year. This applies not only to the keeping quality of the 

 berries from a single bog but to the crop of an entire district. 



Although this variation in keeping quality from year to year is noted in all 

 the cranberry growing regions of the United States, this quality may vary de- 

 cidedly for different sections for the same year. This is well illustrated by the 

 results of the keeping tests made in Chicago during the years 1926 to 1929 for 

 the purpose of determining the relative prevalence of rot-producing fungi in 

 berries from the different cranberry growing sections. Inspection of the graph^ 

 shows that the greatest amount of rot occurred in the storage lots from New Jer- 

 sey and Massachusetts in 1927 and in the storage lots from Wisconsin in 1926. 



Determining the Keeping Quality of the Crop 



Securing an accurate estimate of the actual keeping quality of the crop is much 

 more difificult than might generally be supposed, since a large part of the decay 

 and, indeed, the most important part from the commercial standpoint, occurs 

 after the berries are packed and shipped. Decay which occurs in storage before 

 packing can be estimated with considerable accuracy. Estimates of decay after 

 shipment, however, insofar as they rest on the judgment of sales agents and in- 

 spectors, are almost always influenced by market conditions. Inevitably, re- 

 jections are most frequent on falling markets and it is during such periods that 

 the condition of the fruit is brought most definitely to the attention of the grower 

 and his sales representative. On the other hand, during years of short crop or 

 rising markets, much relatively inferior fruit may be bought and sold without 

 notice or rejections and the feeling gains credence among growers and shippers 

 that the crop has been "good." 



There is no adequate means of measuring quality from the consumers' stand- 

 point, which is probably only one of the reasons why his point of view is so rarely 

 considered by students of plant disease problems. 



^Shear, C. L., Stevens, N. E., and Bain, H. F. Fungous diseases of the cultivated cranberry. 

 U. S. Dept. Agr. Tech. Bui. 25S, 1931. 



