92 THE CHERRIES OF NEW YORK 



All stone-fruits suffer more or less from an excessive flow of gum. 

 The name gummosis^ is generally applied to these troubles. Gumming 

 is much more prevalent in the far West than in the East but is to be 

 found wherever stone-fruits are grown. This excessive gumming is a 

 secondary effect of injuries caused by fungi, bacteria, insects, frost, sun- 

 scald, and mechanical agencies. There is a good deal of difference in the 

 susceptibilities of varieties and species to this trouble, the Sweet Cherry 

 suffering much more than the Sour sorts and varieties of other species 

 having hard wood suffering less than those having softer wood. There is 

 less gummosis, too, on trees in soils favoring the maturity of wood; tinder 

 conditions where stin and frost are not injurious; and, obviously, in 

 orchards where by good care the primary causes of the diseases are kept 

 out. 



A number of diseases of the trunk arise from mechanical injuries 

 from wind, sun, frost and hail. Few, indeed, are the fruit-growers whose 

 trees are not occasionally damaged in one way or another in the vicissitudes 

 of a trying climate. Very often these mechanical injuries are followed 

 by fungal parasites or insects so as to make it difficult to distingmsh the 

 primary from the secondary trouble. There is a wide difference in the 

 susceptibility of Prunus avium and Prunus cerasus to such injuries, the 

 Sweet Cherry, with its softer wood, being much more easily injured by 

 any and all stresses of weather than the Sour Cherry. In the main the 

 elements cannot be combated but low heading of the trees is a preventive 

 from sunscald, at least, and sometimes may have a favorable effect in 

 preventing wind and frost injuries. 



CHERRY INSECTS 



Insects troubling cherries are numerous but hardly as destructive as 

 with other tree-fruits. Entomologists list about 40 species of insects 

 attacking cherries and about as many more occasionally attack the varie- 

 ties of one or the other of the two cultivated species. The majority of 

 these pests came with the tree from its habitat over the sea but several 

 have come from the wild cherries of this continent. 



Of the pests peculiar to the cherry alone, possibly the cherry fruit 

 maggot^ (Rhagoletis cingulata Loew) is, the country over, as troublesome 

 as any. The adult insect is a small fly with barred wings which lays eggs 



' Hedrick, U. P. Gumming of the Prune Tree, Ore. Sta. Bui. 45:68-72. 1897. 

 2 Slingerland, M. V. Bid. Cor. Ag. Ex. Sta. 172: 1899. 



