4i8 



CERTAIN INSECT AND FUNGOUS PESTS. 



are confident that it is widespread and destructive. In 

 many cases it may have been confounded with the phy- 

 tophthora, although it differs from it in all essential 

 points. Almost invariably the leaf begins to die at the 

 tip, which curls under. The disease progresses slowly 

 toward the stem, and finally the entire leaf curls up, 

 dries, and wastes away, leaving the bare stalks, which 

 then also die down. We have never found a sign of the 

 white mildew, which accompanies the ordinary blight, 

 nnd is seen on the under side of leaves affected by the 

 phythophthora. This new blight has usually made its 

 appearance quite early in the season, long before even 

 the early potatoes had reached maturity. While it does 

 not attack the tubers, it prevents their full development 

 by killing the foliage prematurely. Undersized potatoes 

 of poor quality, because immature, are the result. 



The disease is giving us as much trouble on our 

 grounds here in New York as it did in New Jersey. 

 Professor Halsted finds that the same bacteria attacks 

 the potato, tomato, cucumber and melon, and believes 

 that spraying with Bordeaux mixture checks the spread 

 of the disease. We are not confident of this, as repeated 

 sprayings last season did not seem to have marked effect. 

 Entire success with this treatment should not be ex- 

 pected, unless spraying is begun early, and repeated fre- 

 quently. A great deal of experimenting in this line is 

 yet needed. 



The new blight has recently been spreading in Ver- 

 mont, and the Experiment Station of that state sum- 



marizes the distinguishing features of the true blight and 

 the new disease as follows : 



"(i ) The true blight attacks the leaf at any point, 

 and generally works rapidly. In the new disease the 

 leaf begins dying at the tip and dies slowly backward, 

 the leaf drying and curling meanwhile ; and the whole 

 progress of the disease is comparatively slow. (2.) In 

 the true blight the black spots on the leaves are fringed 

 on the under side by a delicate fungous growth. In the 

 new disease this is never found. (3.) The true blight 

 may be expected in the latter part of the summer, es- 

 pecially in August, and only during warm wet weather. 

 The new disease may be expected earlier and develops 

 in cooler and dryer weather. (4.) Following the blight 

 the tubers may be expected to show more or less of rot, 

 especially dry-rot, if soil is heavy or moist. No such 

 rotting of the tubers occurred last year in Vermont as a 

 consequence of the new disease." 



We also suspect that there is a soft-rot of the tubers 

 which is not accompanied by blight of the foliage. This 

 rot did a great deal of damage to some crops of early po- 

 tatoes in this state, while late potatoes in the same vi- 

 cinity remained entirely free from disease. The early 

 potatoes came to full maturity, their tubers appeared 

 sound, and the foliage died down in a seemingly 

 natural manner. Then the tubers began to rot, and 

 continued to rot badly even after they were dug and 

 stored. We shall watch for the reappearance of this 

 same rot this year, and try to discover its true nature. 



