202 INTERNATIONAL CONGRESS OF VITICULTURE 



This trim blue beetle has been a serious pest in New York vineyards 

 at various times and it is claimed by early entomologists to have caused 

 an immense amount of damage to grape growers. It has appeared in the 

 literature for almost a century and during the latter part of that period 

 it has been mentioned almost annually by many observers. For these 

 reasons this species is one of the best known of our grape pests so far as 

 distribution and feeding are concerned. Many of the details of its life 

 history and habits have been described during the past 35 years. With 

 all these observations there are many facts regarding the life cycle and 

 especially the ecology which will bear careful observation and experi- 

 mentation before this species becomes as well known as many of our 

 important economic species. 



Economic Importance. 



The relative importance of this insect as a grape pest will be given 

 by another, but there are several observations regarding the species in 

 the Chautauqua and Erie grape belt which may be of interest. After care- 

 ful study of this pest for six years, during several of which there have been 

 severe infestations, it appears that all accounts of the loss of fruit by this 

 insect are correct. However, it is difficult to reconcile the statements of 

 most observers regarding the killing of the vines by the beetles and our 

 own observations. In a very severe outbreak in one locality in 1913 the 

 insects were as numerous as one finds mention of in the literature, yet 

 few vines were killed in a vineyard of six acres (19 vines out of 4020, .4 

 of one per cent). The only explanation offered is that it is possible that 

 in former outbreaks a large number of beetles were concentrated on a 

 small number of vines owing to the vineyards being smaller and not in 

 such close proximity to each other as at present. Whatever the explanation, 

 the number of vines killed at present is almost nil when the area of the 

 vineyards is considered. The damage to the crop may be great in restricted 

 areas but it is small when compared with the tonnage of this grape belt. 

 Unfortunately all the loss occurs in a few vineyards and, to the owners of 

 these, this pretty blue insect is a source of considerable financial loss. 

 Under New York conditions, this flea-beetle is found each year in a few 

 localities. The proximity of waste land having wild grapes appears to 

 be the controlling factor in its distribution, for it evidently does not thrive 

 in cultivated vineyards exclusively. In the region just mentioned not more 

 than one per cent of the area is infested. 



Food Plants. 



The chief food plants of the grape-vine flea-beetle are the various 

 species of wild and cultivated grapes found in the eastern United States. 

 Most accounts are in connection with injury to cultivated vines. The 

 occasional feeding on other food plants evidently occurs when the beetles 

 have accidentally gotten away from grapes. The writer has made fall and 

 spring observations on the feeding habits of this beetle for several years, 

 including the examination of a number of common plants commonly re- 

 ported as fed upon by this insect. The following species showed no feed- 



