AO CIRCULAR 639, U. S&S. DEPARTMENT OF AGRICULTURE 
poison mixture, the ground on which it is scattered should be left 
uncultivated for at least 2 days after an apphcation is made, as the 
bait 1s inaccessible to the grasshoppers when covered with dirt. 
Owing to the rush of spring work it sometimes happens that the 
transplanting of tobacco plants into the shades precedes the con- 
struction of the shade walls. Without these protecting barriers grass- 
hoppers frequently enter shade fields from outside areas. In instances 
where grassland adjoins shade fields (fig. 46) this is nearly always 
the case. 
Under these conditions the bait should be scattered in a wide strip 
around the borders of the shades as well as within the shade-field 
areas. Applying poisoned bait to infested grassland immediately 
adjacent to tobacco shades is a worthwhile practice even when the 
Figure 46.—An area of grassland adjoining a tobacco shade field. Fields of 
this type are favorable breeding grounds for large numbers of grasshoppers. 
walls are in place, as a certain number of smal] grasshoppers invari- 
ably work their way inside. 
The poisoned bait will kill a large percentage of the insects present 
at the time of application. They do not die immediately after eating 
the bait but continue to succumb over a period of several days. The 
dead grasshoppers are rather difficult to find, especially if they are 
small, immature forms. Frequently they are torn apart and carried 
away by ants. The results of a bait application should therefore be 
determined by the absence of live grasshoppers rather than by the 
numbers of dead Tpet es observed. 
The bait should be applied by preference during warm, pleasant 
weather while the insects are actively feeding. If the weather is 
very hot and dry the bait particles will become hard and unattractive 
after a few hours. Under these conditions, 2 quarts of low-grade, 
cylinder lubricating oi] are sometimes added to 50 pounds of the 
bran mixture. Bait containing oil not only scatters more easily 
| 
| 
| 
| 
