208 MANUAL OF AMERICAN GRAPE-GROWING 



struct ion of the pupae while in the ground. When the beetles 

 are present in large numbers, many of them may be destroyed 

 by spraying with a mixture of cheap molasses and arsenate of 

 lead, using molasses at the rate of two gallons to a hundred gal- 

 lons of water and the arsenate of lead at the rate of six pounds. 

 This should be followed by a second spraying a week later, 

 using bordeaux mixture (4450) and three pounds of arsenate 

 of lead. This second spray serves to repel migrating beetles 

 from the vines. The molasses spray is ineffective unless sev- 

 eral days of fair weather follow the spraying, as rain washes 

 the material from the foliage. Bordeaux mixture is not easily 

 affected by rain. In moderately infested vineyards, bordeaux 

 mixture and arsenate are used instead of molasses and arsenate 

 of lead, followed in about ten days with a second application 

 of the same material. 



An effective method of reducing the number of beetles is 

 the destruction of the pupae. This is best done by leaving a 

 low ridge of earth under the vines at the last seasonal culti- 

 vation to remain until most of the larvae have pupated, and 

 then be leveled with a horse-hoe and later with a harrow. 

 The horse-hoe and harrow crush many of the pupae and break 

 the cells of others to the great destruction of the pest. This 

 latter method of control is not adequate in itself and in bad 

 infestations both should be used. When the infestation is 

 only moderate, this latter method is not advised, owing to the 

 lateness of the time of horse-hoeing. It is good horticultural 

 practice to horse-hoe the latter part of May or early June. 

 To wait for the pupal stage of the root-worm delays the work 

 until numerous small roots start which would be destroyed by 

 the horse-hoe. Spraying will control a moderate infestation. 



The grape-vine flea-beetle. 



In the warm days of May and June when the buds of grapes 

 are swelling, a shining steel-blue beetle may often be found in 



