4 BULLETIN 837, IT. S. DEPARTMENT OF AGRICULTURE. 



TRAINING SYSTEM. 



The k ' fan " system of grape training (PL III, fig. 1) which is used 

 consistently in northern Ohio with the Catawba variety and a modi- 

 fication of which is used with Concords, is not generally practiced in 

 any of the other commercial grape sections of the country. 



This "fan " system consists in securing the bearing canes from the 

 old vine head between the ground and the first wire and tying them 

 up obliquely to the first and second wires, forming a V open at the 

 top. Although two canes are the rule with the Catawba variety, 

 when the thrift of the vine allows of more than two the additional 

 canes are also carried up obliquely, completing the fan from which 

 the system takes its name. As the young shoots bearing the clusters 

 grow to a sufficient length they are tied up vertically to the middle 

 and top wires. An effort is made to have these shoots spread, but 

 to economize labor in tying they are often bunched 2 to 4 in a place. 

 This system of training spreads the grape clusters all through the 

 vine from the ground to the top wire and covers them almost com- 

 pletely with foliage and shoots (PI. Ill, fig. 2). These conditions 

 explain in part the failure to cover the grape clusters when any set- 

 nozzle method of spraying is used, particularly when the spraying 

 is done late in the season and considerable vine growth has been at- 

 tained. 



VARIETAL INFESTATION. 



Several commercial varieties of grapes are present in northern 

 Ohio, affording opportunity for observation on the relative infesta-. 

 tion of the different varieties b}^ the grape-berry moth. A list of 

 varieties observed, beginning with the most heavily infested and 

 ending with the least, is as follows : Shride, Elvira, Clinton, Eeisling, 

 Catawba, Norton, Niagara, Delaware, Agawam, Ives, Concord, Wor- 

 den, and Moores Early. 



In general it seems that the early-blooming varieties like the 

 Shride and Clinton become heavily infested with the first-brood 

 larva 3 , and late-harvested varieties like Catawbas and Nortons be- 

 come heavily infested with second-brood larvse. 



SEASONAL HISTORY. 



The grape-berry moth completes one life cycle and a part of an- 

 other each season. This insect is injurious only in the larval stage. 

 There are two broods of worms or larvae every season (PI. I, fig. 1), 

 the second much more numerous and destructive than the first (PI. 

 II, fig. 1). Since an understanding of the main points in the life 

 history of the insect is necessary for the best application of control 

 methods, a brief summary will be given. 



