CLOVER AND ALFALFA SEED CHALCIS-FLY. 15 
such a depth that the emerging adults are unable to reach the sur- 
face, because the slightest covering of moist soil will cause many 
of the infested seeds to mold, and prevent development of the pupal 
or adult stages. 
The necessary cultivation can be accomplished by the use of an 
alfalfa cultivator, spring-tooth harrow, or a disk. Care should be 
taken that the surface of the field is left smooth, to facilitate close 
cutting, as well as to prevent clods and gravel from being taken up 
with the seed when the seed crop is harvested. 
IRRIGATION OF ALFALFA SEED FIELDS. 
Whenever possible, the alfalfa seed grower should do most of his 
irrigating in early spring, or before the seed crop is grown. Where 
this can be practiced, two important points may be gained. First, 
the tender, rank growth of alfalfa usually following irrigation will 
be removed as an early fodder crop, and a steady growth of more 
substantial stems will take its place to produce the seed crop. Second, 
irrigation of a seed field stimulates the emergence of the chalcis- 
flies which remain within the infested seeds upon the ground. The 
humidity of the atmosphere* over an irrigated field accelerates the 
emergence of this pest from seeds of the newly forming crop, which 
would otherwise become sufficiently dry to force many of the larvae 
into a resting period. 
It has been supposed by farmers that flooding the seed fields after 
the first crop of alfalfa has been removed would destroy the larvae 
of the chalcis-fly present in alfalfa seeds upon the ground. The 
writer has found that soaking infested seed in water for four or five 
days is not sufficient to kill the larvae resting within the seeds. This 
would render any attempt at their destruction by irrigation im- 
practical. 
CUTTING EARLY PLANTS ON WASTE AREAS. 
The fence lines, ditch banks, and other waste areas where volun- 
teer alfalfa can be found, are among the great sources of infestation. 
It has been found that the chalcis-fly frequently passes through one 
or two generations on this volunteer alfalfa before the seed fields 
are advanced to the point where infestation takes place. Every 
farmer, therefore, in an alfalfa seed-growing district should cut all of 
the standing alfalfa along the fences and waste areas at the time a 
hay crop is cut before he grows a seed crop. Alfalfa seed pods 
should not be allowed to develop anywhere around the field until the 
plants of the regular seed crop have begun to form pods. 
CAREFUL CUTTING OF HAY CROPS. 
It is of the greatest importance that special care should be exer- 
cised in cutting alfalfa or red clover before the seed crop is grown. 
