The Alarm of Insects and Fungi. oY 
an area of high pressure. It is evident, too, that 
no amount of legislative enactment could have stayed 
the dispersion unless it should have forbidden the 
planting of apple trees. 
As a matter of practice, the energetic and intel- 
ligent fruit-grower will think last and least of the 
parasite factor when locating his plantation, for 
this factor is variable and migratory, and, moreover, 
there are means of keeping most fruit pests under 
control. Insects and fungi are apt to be bughears— 
sometimes literal bugbears—to the fruit-grower; but, 
after all, they are rarely to be counted upon as _ per- 
manent factors, and they are the direct and perhaps 
the most efficient means of keeping the farmer in a 
state of mental alertness. There are a few cases, of 
course, to which these remarks will not well apply, 
but they are clearly exceptions. One of these is 
the dreaded nematode root-knot of the southern 
states, and one might seriously hesitate in planting 
peaches where the ground does not freeze deep 
enough to destroy the pest. The professional ex- 
perimenters can determine the course of the life- 
histories of the various pests, and can point out 
their most vulnerable points, and may even devise 
general means for their eradication; but the final 
application of this knowledge is a local problem, 
which each man must work out for himself. Laws 
are generally of little avail for the destruction of 
pests, except in those few cases in which disease is 
more or less permanent or perennial, and in which 
there is no practicable recourse but to destroy the 
