8 FARMERS’ BULLETIN 636. 
become heated and decay, most of the insect life will be destroyed. 
Unless it is possible to treat the screenings in this manner they should 
be burned before the growing season opens in the spring. 
BURNING FENCE LINES AND CHECK RIDGES. 
Many of the alfalfa seed pods along check ridges and fence lines 
may be destroyed by burning off the weeds and alfalfa, as is shown 
in figure 9. This should be done either in the fall or early spring. 
PLANTING CLEAN SEEDS. 
In purchasing alfalfa seed, farmers should insist upon having seed 
which has been well cleaned after thrashing and should never plant 
Fic. 8.—An alfalfa straw stack, showing the ground covered with screenings in which many chalcis-fly 
larvee are hibernating. (Original.) 
the uncleaned product in new fields. In many localities much of the 
seed is sold both by farmers and by local dealers without first having 
been cleaned. The product of such seed when harvested from the 
late crops frequently contains a 10 to 15 per cent infestation of hiber- 
nating chalcis-fly larve. The planting of this uncleaned seed fre- 
quently gives the chalcis-fly a start in the new field, as well as result- 
ing in a poor stand. 
CUTTING THE SEED CROP. 
It is not an uncommon practice for the farmer to allow the seed 
crop to remain on the fields an excessive period in order that more of 
the green pods may develop. In such fields on the same plant are 
found ripe pods bursting open, as well as fully developed, half-grown, 
and newly forming pods. 
Observations show that many of the chalcis-flies infesting the earlier 
or first pods have had sufficient time to complete their life develop- 
tte 
