THE ALFALFA CATEEPILLAR. 31 
The damage in some alfalfa fields is quite often apparently cor- 
related with the condition of the soil. A field seriously damaged 
often reveals a poor soil — at least a soil not well adapted to alfalfa 
culture, and consequently producing a slow-growing crop. Of course 
not all of the fields damaged were of poor soil ; some of the very best 
alfalfa fields were seriously ravaged, but in these cases this was often 
attributable to other factors. Sandy loams or light soils are the 
best for alfalfa production, and consequently are the least damaged, 
owing to the fact that the alfalfa, growing more rapidly, is often 
able to recover from insect attacks and be ready for harvest before 
any noticeable damage has been done. A heavy soil can be improved 
and the growth of the alfalfa increased by deep plowing and thor- 
ough preparation of the seed bed at time of seeding the crop and 
then by renovating the alfalfa several times a year, either by disking 
or by the use of an alfalfa renovator. By such a procedure in irri- 
gated regions the soil will more readily take water, and thus plant 
growth will be stimulated. 
A farmer who attempts to use up-to-date and proper cultural 
methods is unfortunate indeed when his alfalfa fields, for which he 
is caring properly, are just across the fence from fields that are run 
down, and hence are breeders of insects. No matter how careful his 
efforts, some damage may be done owing to reinf estation of his fields 
from the butterflies supplied by his neighbor's field. Nevertheless 
enough may be accomplished through his own efforts to pay many 
times. 
Again, the amount of water applied is often insufficient, sometimes 
because of neglect on the part of the rancher, and sometimes because 
of scarcity of supply. The former case is under the rancher's con- 
trol; he should use care in applying the water and should eliminate 
waste. Sufficient water should be used to provide for the prompt 
development of the alfalfa crop, for in this way the farmer can 
reap his crop earlier and before the caterpillars have effected much 
damage. 
Soon after agents of the Bureau of Entomology began observations 
and experiments looking toward the control of the species it was 
noticed that damage to alfalfa was often, although not always, 
associated with careless methods of farming and a lack of appre- 
ciation on the part of some ranchers of the benefits to be derived 
from careful, clean cultural methods. This is sometimes due to the 
fact that the rancher is trying to cultivate more land than it is 
possible for one man to farm successfully with the limited amount 
of labor and capital at his disposal. A great many times poor man- 
agement is responsible for a failure where other methods would have 
meant success. 
