1916.] PUBLIC DOCUMENT — No. 31. 63a 



apple, brown rot of peach, plum and cherry, leaf curl of peach, 

 downy mildew of grape, anthracnose of bean, bacterial blight of 

 bean, late blight of celery, tomato scab, botrytis stem and bud 

 rot of peony, rust of antirrhinum, chestnut canker and an- 

 thracnose of sycamore. 



The damage to the potato crop due to the late blight was 

 especially heavy throughout the State. It was noticeable, how- 

 ever, that on those fields repeatedly sprayed with Bordeaux 

 mixture comparatively little loss resulted. While spraying is 

 quite generally practiced by potato growers, there is a tendency 

 to be satisfied with one or two applications, whereas in such a 

 season as the last the applications should be made at intervals 

 of ten to fourteen days throughout the growing period of the 

 vines. 



It is noteworthy that downy mildew of cucumbers was re- 

 ported in greenhouses in the eastern part of the State as early 

 as May first, which was fully a month earlier than this disease 

 usually makes its appearance. It continued to cause serious 

 damage during the entire summer, and was present in some 

 houses long after the first fall frosts. It resulted in total failure 

 of the cucumber crop in some places, and heavy loss resulted 

 everywhere, both to indoor and outdoor crops. A similar out- 

 break of the disease occurred in 1913. 



In the past some concern has been felt over the possibility 

 that powdery scab of the potato might be introduced into the 

 State. In order to obtain evidence regarding the ability of the 

 powdery scab organism to cause the disease in this State, the 

 department undertook to test the matter in co-operation with 

 the United States Department of Agriculture. Experimental 

 plantings of infected tubers in two-foot tile filled with soil from 

 station plots failed to produce any tubers showing the slightest 

 evidence of powdery scab. On the other hand, diseased tubers 

 were produced in soil from the same source sent to Maine for 

 the purpose of investigation. This evidence, coupled with 

 similar results obtained in other eastern States, while not con- 

 clusive, suggests the probability that powdery scab will not 

 become a troublesome disease of the potato in Massachusetts, 

 and that climatic conditions play an important part in its dis- 

 tribution. 



