CONTROL OF THE GRAPE-BEERY MOTH. 13 



The effect of this treatment is to prevent the moths from escaping 

 through the covering of earth. 



In a number of vineyards where this method of control has been 

 practiced, check rows were maintained in which the earth was 

 removed early in the season, in order to determine, if possible, the 

 effects of the practice. No definite results were obtained. If small 

 checks were left the flight of moths obscured the results altogether; 

 and in larger checks variation of infestation interfered. In some 

 vineyards the infestation appeared to be reduced greatly, but in none 

 was it controlled. 



The principle of this practice was proven correct, however, by a 

 small experiment in the insectary yard during the season of 1916. 



Three lots of 300 cocoons each, collected in the fall of 1915 and 

 wintered in the insectary yard, were placed in 8-inch flowerpots. Two 

 lots were covered with from 2| to 3 inches of earth; the third was 

 left uncovered. The emergence record totals as follows: 



From 600 cocoons buried under earth no moths emerged. 

 From 300 cocoons not buried 103 moths emerged. 



In a number of small lots 60 cocoons were placed in glass vials 

 where the action of the moths after emergence could be observed. 

 These cocoons were covered with earth at depths varying from -|- 

 inch to 3 inches. Upon emergence none of the moths were able to 

 work their way upward through the covering of earth. It should be 

 remembered, however, that results as satisfactory as these can not be 

 expected under field conditions. 



"Horse hoeing" away from the vines, if done during the grape 

 blossoming period, would also destroy grape-rootworm pupae which 

 are transforming at that time (13, 18). 



SPRAYING. 



Experiments with poison sprays were conducted during each of the 

 three seasons. All of the vineyards but one were planted to Concord 

 grapes, which is the standard variety for this grape-producing region. 

 In 1916 experiments were conducted also in a single vineyard of 

 Niagara grapes. 



Weather conditions affecting spraying operations and results 

 differed strikingly during the three seasons. Records from the 

 Weather Bureau station at Erie, Pa., on Lake Erie, 16 miles west of 

 North East, showed that in 1914 the months of July and August 

 were nearly normal. The next year was colder with excessive rains 

 during these two months, while the corresponding period of 1916 

 was very warm and dry. The average mean temperature for these 

 two months in 1915 was 2.4° below normal and the rainfall was 7.95 

 inches above normal. In 1916 the average mean temperature was 

 3.7° above normal and the rainfall was 3.39 inches below normal. 



