438 iiKl'OUT UK TllK lloKTlCULTUKIST OF THE 



Occasionally, they occur also on rlu' trunk above ground. In all 

 cases the knots arc detrimental to the trees and when they occur 

 at the crown the tree is worthless. 



The disease is common in s(jnie of the nurseries in the State. 

 The cause of it is wholly unknown. There are indications that 

 it is infectious but this has not been proven. 



Similar knots occur on the roots of the raspberry, blackberry, 

 pear, apple, plum, apricot, grape, and a few other w'oody plants. 

 Among friiit growers it is the popular opinion that the disease is 

 the same on all of these different plants, and that any one of 

 them mav comnumicate the disease to the others. However, this 

 has not yet been demonstrated by carefully conducted experi- 

 ments. 



Treatment. — IsTo remedv is known. Affected trees should 

 never be planted. It is not even safe to plant trees from which 

 the knots have been removed. Avoid planting fruit trees in soil 

 known to be badly infested by the disease. 



FKUIT KOT OK liIPE ROT. 



(Monilia frudigena P.) 



The ripe rot of the peach is caused by the same fungus as that 

 which produces the ripe rot of cherry and plum. It is discussed 

 on age 420. 



Treatment. — Chester^' who has given special attention to this 

 subject advocates spraying with Bordeaux mixture just before 

 the blossoms open and again after the fruit sets. Spray with 

 copper acetate (finely powdered, 8 ounces to the barrel), when the 

 fruit is ripening. Copper acetate does not discolor the fruit as 

 Bordeaux mixture does. Observe the caution given above con- 

 cerning the liability of injuring peach foliage by spraying. 



GUMMING. 



The formation of gum by the apricot, cherry, peach or plum 

 may follow any injury by cuts or bruises or by the attacks of 



27 Chester, F. D. Ninth Ann. Kept. Del. Agr. Exp. Sta., 1897: 28. 



