372 fvEPOKT OF THE Uepakt.mem" of Exto.mology of the 



vines that yearly are extensively infested by the leaf-hopper. Like- 

 wise serious infestation in any vineyard has a similar influence on 

 the amount of wood produced and the amount of fruit grown. 

 This is cumulative in its eifect and can be shown best by weighing 

 the crop from treated and untreated areas year after year. In the 

 aggregate the quantity of fruit lost during years of average in- 

 festation has not been conspicuous enough to attract attention. It 

 is in the exceptional years, as in 1901-2, that the loss is sufficient 

 to cause alarm and action on the part of the grape growers. One 

 important effect of average infestation is the poor quality of fruit 

 from infested vineyards. The Concord grape when well ripened 

 is dark purple and sweet, but when the leaves are injured by grape 

 leaf-hoppers the fruit has a red appearance and a rather insipid, 

 sour taste. The decrease in the amount of sugar in such fruit 

 makes it especially undesirable for packing in four-pound and 

 eight-pound baskets since choice table grapes should be of excellent 

 quality. Poorly ripened grapes will not be used by the manufac- 

 turers of grape juice. Since the best prices are being paid for 

 grapes for these two purposes, it follows that the leaf-hopper may 

 cause serious loss by depreciating the quality of the fruit. How- 

 ever, growers as a whole pay little attention to the attacks of the 

 " hopper " since grapes of poor quality usually fetch as good prices 

 as superior fruits because of faulty methods in marketing. With 

 the better system of packing and grading grapes, which must come 

 if Chautauqua grapes are to be worth growing, the importance of 

 controlling the pest will generally be better appreciated. 



SPECIES AXD VARIETIES OF GRAPE LEAF-HOPPER IX CHAUTAUQUA 



COUNTY. 



The species of grape leaf-hopper most common on Concord 

 grapes in Chautauqua county is Typhlocyha comes Say. There is 

 much variation in this species, although the typical form prevails. 

 Occasionally one finds variety octonotata Walsh. The typical 

 comes, during the summer, has zigzag yellow lines and three b^ack 

 spots on the elytra: one on the costal (outer) margin, which is 



