62 THE BLACK-KNOT. 



troyed. The sheets may be expanded upon square or rounded 

 frames hinged together so as to be folded up, or they may be 

 mounted upon a wheelbarrow for convenience of moving about, 

 as shown in the accompanying Figure No. 47. The jar must be 

 very sudden to bring down the prey, and is best done with a 

 wooden mallet covered with a thick cloth pad or a long, heavy 

 stick padded at the end. This work must be kept up for three 

 weeks from the time the fruit is the size of a pea; it is effectual 

 and not very expensive. 



Planting the trees in poultry-yards is also a sure way to secure 

 the fruit from the attacks of the curculio. The fowls probably 

 catch the beetles as they come out of the ground, and also the 

 larvae as they escape from the fruit. If planted in large quan- 

 tities, probably the addition of swin.e to destroy the falling fruit 

 containing the larvse would be advisable. 



The Peach-Borer, Fig. 48, Page 56, is often injurious to the 

 roots of the Plum, and the same remedy should be applied as 

 for the peach-tree. 



The Rose-Bug, described under those insects injurious to the 

 grape, Page 80, is often very destructive to the foliage, especially 

 to young trees. The application of pyrethrum powder, espe- 

 cially the kind known as Buhach, if applied in the evening, will 

 paralyze them so that the bugs will fall upon the curculio frame, 

 when they may be very easily destroyed. 



DISEASES. The Black- Wart or Black-Knot, is the most des- 

 tructive disease that the Plum is subject to. It is a fungus, 

 (Sphceria morbosa,) the spores or seeds of which germinate upon 

 the tree, generally upon the branches, in the spring. The roots 

 of this fungus plant, known as the mycelium, penetrate the tissue 

 of the Plum tree; the tree puts forth an increased growth to 

 overcome or overgrow the injury of the fungus itself, thus pro- 

 ducing the black wart, so often seen upon old Plum trees and the 

 common sour cherry. The spores of this fiingus do not ripen, 

 until winter, when they are scattered, and are ready to germin- 

 ate again in the spring. 



The Remedy. No application has as yet been discovered that 

 will destroy or stop the growth of the warts when they appear. 

 They must be removed with the knife as soon as they begin to 

 develop and be burned. Cut out every vestige of diseased wood, 

 whether upon the trunk or branches. If a large cut is made 

 upon the trunk or main branches, the wound should be covered 

 with paint or grafting wax. Healthy, vigorous trees are much 

 less liable to this disease than weak ones. 



ROTTING OF THE FRUIT. This occurs, as in the peach, in 

 moist, warm weather, and when the trees are overloaded. If the 

 directions given for the production of choice fruit and the pro- 

 duction of healthy, vigorous trees be followed, the grower will 

 not be much troubled by his fruit rotting upon the trees. 



