200 INTERNATIONAL CONGRESS OP VITICULTURE 



Keeping bush fruits some distance from vineyards. Along the Hudson 

 river it is customary to interplant grapes with raspberries and such vine- 

 yards are seriously infested practically every year. In other sections 

 grape growers often plant raspberries in close proximity to vineyards and 

 the vines near such plantings are often seriously infested. Since we have 

 found that the raspberry is an important spring food of the leaf-hopper 

 the reason for this is obvious. Whenever possible these two fruit plants 

 should not be planted near each other. 



Retardation of suckering. A common vineyard practice is to remove 

 the shoots which grow near the base of the vines. This is usually done 

 during June a logical time ordinarily. However, during periods of attack 

 by the leaf-hopper, it is better to allow these shoots to remain until early 

 July. The adults dislike to be disturbed and to avoid this seek the lowest 

 foliage on the vines and here lay their eggs. When this is defiled by 

 excrement and feeding they seek the leaves higher on the vine. Usually 

 this movement to the higher foliage occurs late in June if the suckers are 

 allowed to remain, but if these are removed early in June, the insects injure 

 the foliage which is to remain all summer. By allowing these suckers to 

 remain until the first week of July and then removing them the more 

 permanent foliage is saved from injury and any nymphs and eggs are 

 destroyed by the dying of the foliage after being removed. 



Spraying to kill the nymphs. No spraying operations that have been 

 tried have proven practical against the adults but the use of contact 

 insecticides to kill the nymphs has been recommended for a number of 

 years. From the standpoint of safety to foliage, cost of material and 

 effectiveness nothing has been found better than nicotine sulphate diluted 

 so that .02 of one per cent of the material is present in the spray solution. 

 Commercial nicotine sulphate usually contains 40 per cent nicotine and at 

 this strength only one-half pint is required to each 100 gallons of spray 

 material. 



The question of application is very important for it is absolutely neces- 

 sary to hit the bodies of the nymphs with the spray material to be effective. 

 A common method of application is by means of trailing hose having a 

 short extension rod with nozzles set at right angles attached to a power 

 sprayer. This method requires three men one to drive and two to handle 

 the nozzles. It is a very effective method and in vineyards planted on 

 steep slopes is the only one that can be used. The cost of application by 

 this method as well as the disagreeable effect of the material on the 

 operators, has led to the development of several types of machines which 

 can be used, in level vineyards, to deliver the spray against the underside 

 of the foliage. Space forbids our discussion of these at this time but 

 anyone interested in them can secure illustrations and descriptions of the 

 same in Bulletin No. 19 of the United States Department of Agriculture 

 and Bulletin No. 244 of the New York Agricultural Experiment Station. 



In order that spraying to control the grape leaf-hopper be effective, 

 the men operating the apparatus must use care and be thorough in every 

 detail of the operation. 



