488 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



still more. At first, it is more or less difficult for the driver to ride 

 astride of the logs and barrel but by balancing himself, by means of two 

 short sticks, one in each hand, the difficulty is soon overcome. The 

 logs and barrel may be used each morning to keep the sides of the furrow 

 pulverized and smooth, in which condition the larvae cannot attain a 

 foothold, and may be used frequently through the period of maximtmi 

 migration to kill larvae in the ditch. 



On very light soil, such as is found occasionally in this section, as 

 sandy bars, the ditches with post holes at everj^ fourteen feet serve the 

 purpose, but with post holes the ditches cannot be dragged and the post 

 holes on heavy soils were found to be useless. 



I 



FACTORS DETERMINING LOCAL INFESTATION OF THE 

 GRAPE BERRY MOTH 



By J. G. Sanders and D. M. DeLong, State Capitol, Harrisburg Pa. 



Throughout the great grape growing areas in the Eastern United 

 States especially, the Grape Berry moth has been rightly considered a 

 very important pest. Many years in the aggregate have been spent by 

 a number of men in attempting to control this pest, and all of the ex- 

 perimental work carried on to date has had as its basis the poisoning 

 of the larvae. Although some attention has been given to cultural 

 methods, practically no thorough study has been made of natural 

 conditions under which the moth survives, and little comparison of 

 areas of infestation with those uninfested has been made. The eco- 

 logical factors often must be considered in the distribution and survival 

 of a pest. 



For the past three years, 1918 to 1920 inclusive, a survey and study 

 has been carried on in the North East, Pa., area of the Erie-Chautauqua 

 grape belt, in which an area of approximately thirty-two square miles 

 was given careful consideration, and approximately three hundred 

 vineyards were examined. Vineyards having all types of topography 

 were visited and inspected during these examinations, and adjoining 

 vegetation combined with the various degrees of attention and culti- 

 vation were carefully noted. The determination was made of the 

 extent of infestation and the conditions controlling it. It has been 

 definitely shown that grape berr^^ moth infestations occur in the vineyards 

 in a very spotted and localized manner. As a rule a single field is neither 

 entirely nor uniformly infested, and its condition is not an index of the 

 adjoining fields, unless similar conditions occur. 



