14 THE ALFALFA CATERPILLAR. 
irrigated immediately after cutting, was not in the least damaged. 
This was a lesson in itself, as it indicated the necessity for prompt 
work. 
PROTECTIVE MEASURES ADVISED. 
Thus from a comparison of observations made in the two classes of 
fields it is possible to derive the following rules for handling the 
crop: 
Do not abandon a field because the caterpillars are beginning to 
damage a hay crop. If the caterpillars threaten the destruction of a 
crop of alfalfa before the hay can possibly mature, mow it at once, 
cutting it low and clean, and in so doing starve a large majority of 
this generation of worms, thereby protecting the next crop as well as 
saving a part of the one already affected. 
Get the ranch in the best possible cultural condition. Irrigate 
often and thoroughly and as soon after cutting as the crop of hay 
can be gotten off the ground. 
Cut close to the ground and clean, especially along the ditch 
banks, borders, and turnrows, as well as in the main part of the field. 
Cut the crop early. When just coming in bloom is the proper 
time. Watch for caterpillars in the early spring crop, and if many 
are observed about grown cut the hay a few days before it is in 
bloom, and thus save the next crop. 
Pasture alfalfa whenever possible, as a minimum amount of dam- 
age occurs in such fields. 
Use the methods just mentioned on early spring crops, no matter 
whether any worms are noticeable or not, and thus avoid any risk of 
having overlooked them. The satisfactory results must come from 
an application to an early crop. 
Renovate every winter, either by disking or by the use of an alfalfa 
renovator, thus disturbing any pupe that may be wintering over, and 
putting the land and alfalfa in condition for good growth the follow- 
ing spring. 
These methods, while they will probably be of value in other see- 
tions, have been tried only in the Imperial Valley of California, and 
they are not specifically recommended for sections where climatic 
and other conditions differ from those found in this valley. 
Approved. 
JAMES WILSON, 
Secretary of Agriculture. 
Wasurnoton, D. C., January 26, 1911. 
[Cir. 133] 
3 9088 0127 
TITUTION LIBRARIES 
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