REPORT OF COMMITTEE ON PUBLICATION 209 



Artificial Control. 



When these beetles appear in a vineyard in immense numbers it is 

 evident that the owner must adopt means for the eradication of the pest, if 

 he hopes to save the grape crop. Three methods of control are practical 

 against the adults, viz., spraying, hand picking and destruction of wild vines. 



Spraying. The bordeaux mixture (100 gals.) and arsenate of lead (6 Ibs.) 

 is distasteful to the beetles so that vines sprayed with this material will be 

 avoided by the beetles which seek unsprayed vines. It is true that such a 

 dispersion often saves the vines, but, as it serves to scatter the insects and 

 does not kill them, can hardly be called a method of control. For several, 

 years we have known that this beetle is fond of molasses and that this ma- 

 terial when added to arsenate of lead serves to poison them owing to its 

 serving as a bait. The lack of adhesion of the arsenate of lead when mixed 

 with molasses makes its use somewhat of a lottery for if rains should appear 

 shortly after spraying, the material will be washed off the vines and thus its 

 benefits lost. Owing to the frequency of rains in New York during May, 

 we do not recommend this material unreservedly, but advise that it be used 

 if rains can be avoided and if the infestation of the vineyard is such as to 

 make spraying practical. 



Hand picking. At first thought this method might be considered too ex- 

 pensive but in practice generally it has been found cheaper than spraying. 

 One of the chief reasons for this is the fact that the attack usually is in a 

 restricted portion of the vineyard and in order to spray this the entire length 

 of the rows must be traversed by the spray outfit thus causing much loss of 

 time. A person with a milk pan, having a diameter of not less than 15 inches, 

 on the bottom of which is a shallow layer of kerosene, can knock the beetles 

 into the pan by striking the canes with a short stick, the pan being held a 

 little below the place where the beetle is sitting. The oil kills the insects 

 almost instantly. In this manner several thousand beetles can be captured 

 in a short time and at slight expense. It usually is necessary to repeat this 

 operation several times but even then the expense is less than that of spray- 

 ing, unless the latter can be done very economically and no bad weather 

 interferes. 



Destruction of wild vines. This method of control is based upon the 

 fact that wild vines are necessary for the insects in the autumn and when 

 these are destroyed the insects seek other places to feed and the vineyard 

 usually escapes injury. 



Spraying during the time the larvae are feeding. There is no period in 

 the life of the grapevine flea-beetle at which it can be controlled more easily 

 than while feeding as larvae. Since feeding usually occurs on the upper 

 surfaces of the leaves it is very easy to place the material where it will be 

 effective. No trouble is experienced in killing the insects by the use of 

 arsenate of lead (6 Ibs.) in water (100 gals.) or if preferred the poison can 

 be used with bordeaux mixture. The application should be made after the 

 maximum number of eggs have hatched. This spraying at times coincides 

 with the first spraying for the grape root-worm but generally a separate 

 application is necessary. The killing of the larvae avoids injury by the 

 beetles the following spring unless a large area of unsprayed vineyards ad- 

 join. Under this latter condition spring migration may cause trouble. 



