ltt tb 
. 
Spraying for the Alfalfa Weevil. 3 5 
The turning point, then, coming from one to two weeks before the 
first crop is ready for cutting, is the best time to spray the field. 
The feeding larve are now most numerous and the conditions for 
poisoning them accordingly most favorable. On the other hand, 
the crop is not yet too badly damaged to recover quickly after the 
killing of the larve. Figure 3 shows the result of treatment at the 
proper time. The work may be done a week earlier or several days 
later, as the owner’s experience and the character of the season may 
dictate. It has been done as early as April 20,,entirely preventing 
damage to the crop, and in other cases it has been delayed until the 
plants had been stripped of their foliage, in spite of which they 
Fig. 2.—A field of alfalfa which has passed the turning-point. The lower foliage is 
still sound, but the tops are white and the buds have been killed. 
were able to recover and bloom. The early spraying, however, 1s 
uncertain, as its success depends partially upon poisoning the adult 
beetles, which feed but little, while late spraying allows the destruc- 
tion to go too far and makes recovery too slow. 
THE TIME OF THE TURNING POINT IS GOVERNED BY 
WEATHER CONDITIONS. 
The time of the turning point varies from year to year with 
weather conditions. If the weevils were affected by these conditions 
in the same way as the alfalfa it might be possible to name a definite 
stage.in growth of the plant at which spraying should be done, but 
this is not always true. 
