9 
* 
A field of peas saved by the use of the brush-and-cultivator method 
is illustrated in figure 5. 
In figure 6 the manner of applying the brush-and-pan method is. 
shown. Figures 4-7, illustrating the practical methods of combating 
the pea aphis, were first used by the late W. G. Johnson in an article 
published in Bulletin No. 26 of this Bureau. 
Cultural methods.—Of cultural methods, there is testimony to the 
value of early planting, the earliest peas seldom being infested, or at 
least only slightly injured. Very large plantings of peas to be used 
for canning have also escaped rayages in some instances, but it may be 
Fia. 6.—Field of peas saved by the brush-and-pan method, showing the apparatus used. 
that atmospheric conditions have had somethihg to do with exemption 
in the cases which have come under notice. 
Rotation of crops is advisable, and it is unwise to plant peas on the 
same portion of a farm or garden, in successive years, or in the vicinity 
of fields of red or crimson clover, or other leguminous plants, such as 
vetch, which are likely to harbor this species. 
As has been said, this insect passes the winter on the plants men- 
tioned, because peas are not available, and it might be possible to 
use small plants of some one of them as trap crops. Crimson clover 
would probably be best because of its conspicuousness and the early 
start that it gets in the spring. On the trap plants the aphides could 
be killed by hand methods, such as brushing from the plants into pans, 
AG-—49 
