122 FRUIT CULTURE. 



common at the West, but less so in New Eng- 

 land. Remedy the same as for curculio. 



The Plum Sphinx and several other cater- 

 pillars feed upon the leaves of the plum to 

 some extent, but have not proved numerous 

 enough to cause serious injury. Hand pick- 

 ing is, thus far, a simple remedy. 



The peach borer, the flat-headed apple-borer, 

 the pear blight beetle, the apple tent caterpil- 

 lar, the forest tent caterpillar, the canker- 

 worm, the fall-web worm, and the pear slug 

 do more or less injury to the plum, and are to 

 be treated as suggested for the apple and pear. 

 The codling moth sometimes injures the fruit. 



Plum Knot (Plowriglitia morhosa). Until 

 recently the cause of this disease has been un- 

 discovered. Superficial observers have jumped 

 to the conclusion that because insects are often 

 found harboring in the large excrescences they 

 are therefore the cause. It is now, however, 

 well established that they are only a conse- 

 quence, the cause being a minute fungus which 

 fastens upon the limbs and trunk of the plum, 

 and also of the cherry. In 1876 Professor 

 Farlow, of Harvard College, published a his- 

 tory of this fungus and of its mode of repro- 

 duction. It appears from his observations and 

 the more recent studies of Professor Scribner 



