36 BULLETIN 19, U. S. DEPARTMENT OF AGBICtTLTUBli 
curved wire teeth, so that when the shield is held beside a vine, the oilcloth will come 
under the vine to catch the '"hoppers" that try to drop to the ground. Cover the oil- 
cloth with the •" stick-em " and all is ready to operate. Two men. each carrying one 
of these light sticky shields on opposite sides of a trellis of vines, can reach over the 
shields, jar the vines to disturb the •"hoppers"* and thus go over an acre of vineyard 
in a little more than an hour. 
In California, where the vines are not trained to a trellis, Mr. 
Qua vie found that a screen cage having the inside smeared with crude 
oil, with one side open and a V-shaped opening cut in the bottom 
to admit the stem of the vine, could be used quite effectively 
in the vineyards to catch the adults before egg deposition com- 
menced. In the course of his field experiments hi California Mr. 
Quayle conducted experiments with suction apparatus for collecting 
the adults from the vines. He also attempted to destroy them with 
torches: by the application of dry powders, including lime, helle- 
bore, and dry sulphur; and also by the fumigation of infested vines, 
both with eyanid and sulphur gas. None of these latter methods 
gave results of a practical nature, and the only mechanical method 
of control against the adults recommended by him is that of the 
screen cage previously mentioned. 
Destruction of leaves and trash. — Many authors have urged the de- 
struction of leaves and trash in and adjoining infested vineyards, 
while the insects are hi hibernation, as a means of lessening then 
numbers. However, since the adults rise in the air and either fly or 
are carried considerable distances by the winds during the migrations 
which take place during the spring and fall, there are usually large 
areas of wood lots and pasture lands at considerable distances from 
vineyards where swarms of the adults may be found during the 
winter. Since hi many cases these areas of rough land are not con- 
trolled by the owners of the vineyards there is slight possibility that 
this cleanuig-up process will be undertaken on a large enough scale 
to be of any great value in lessening the numbers of overwintering 
adults. Furthermore, at the present time there is a strong tendency 
toward the growing of some form of cover crop, such as clover, vetch, 
turnips, rye, oats, etc., hi vineyards as a means of furnishing soil 
protection and fertility; and this is very necessary and desirable in 
most of the vineyards of the Lake Erie Valley. This would have to 
be abandoned if the clean-culture method were followed. Observa- 
tions along this line covering several seasons indicate that where 
cover crops are growing hi badly infested vineyards the number of 
adult grape leafhoppers found among the shelter thus afforded is 
generally very small compared with the number that have migrated 
to adjacent wood lots and rough pasture lands. In fact, it would 
appear that there is a tendency for the larger percentage of adults to 
migrate from the vineyards in the fall, and this migration appears to 
be then chief mode of dispersal as much as a means for securing suit- 
