BULLETIN 198. 



THE GRAPE LEAF-HOPPER. 



205 



The idea that prevails with some, that sulfur is of use in killing the 

 hoppers, is not borne out by facts. Hoppers, in all stages, confined in 

 our breeding cages in the vineyard, thrived well in spite of the fact 

 that large amounts of sulfur were blown into and held in the cages 

 during the frequent sulfurings for Oidium. 



Sticky Shields. Sticky shields have been used to some extent in 

 fighting the grape leaf-hopper, but a large number escape by this 



Fig. 16. Applying air-slaked lime for the nymphs of the hopper by means of the 

 French vermorel machine. 



method so that their use is not thoroughly satisfactory. A sticky shield 

 held on the leeward side of the vine and the hoppers jarred off will 

 catch many, but a large number will not strike the shield. A three- 

 sided box for our California vines works best, but even here many will 

 drop to the ground or fly out on the open sides. In the New York 

 vineyards, two men each carrying light sticky shields three or four 

 feet high and seven or eight feet long on opposite sides of trellised 

 vines, has been found to be a fairly successful method of capturing 

 the hoppers. Probably the best sticky material for use on the shields 

 in this State is the ordinary crude oil. 

 3 BUL. 198 



