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mies of such crops. A most valuable cultural means, therefore, is a 
system of rotation of crops which will prevent the gradual yearly 
increase of the enemies of any particular staple by the substitution every 
year or two of other cultures not subject to the attacks of the insect 
enemies of the first. 
With such insects as the Hessian fly, the squash borers, and many 
others which have regular times of appearance, much can be done, 
also, by the planting of early or late varieties, or by deferring seeding 
so as to avoid the periods of excessive danger. Wherever possible, 
varieties should be selected which experience has shown to be resistant 
to insect attack. Familiar illustrations of such resistant varieties in 
all classes of cultivated plants will occur to every practical man, and a 
better instance of the benefit to be derived from taking advantage of 
this knowledge can not be given than the almost universal adoption of 
resistant American vines as stocks for the regeneration of the vineyards 
of France destroyed by the phylloxera. 
These general notes are by no means new, but their importance jus- 
tifies their repetition, as indicating the best preventive measures in 
connection with the remedial ones already given. 
THE PROFIT IN REMEDIAL MEASURES. 
The overwhelning experience of the past dozen years makes it 
almost unnecessary to urge, on the ground of pecuniary returns, the 
adoption of the measures recominended in the foregoing pages against 
insects. To emphasize the value of such practice, it is only necessary 
to call attention to the fact that the loss to orchard, garden, and farm 
crops frequently amounts to from 15 to 75 per cent of the entire prod- 
uct, and innumerable instances could be pointed out where such loss 
has been sustained year after year, while now, by the adoption of 
remedial measures, large yields are regularly secured with an insig- 
nificant expenditure for treatment. It has been established that in 
the case of the apple crop, spraying will protect from 50 to 75 per cent 
of the fruit which would otherwise be wormy, and that in actual mar- 
keting experience the price has been enhanced from $1 to $2.50 per 
barrel, and this at a cost of only about 10 cents per tree for labor and 
material. 
In the case of one orchard in Virginia, only one-third of which was 
sprayed, the result was an increase in the yield of sound fruit in the 
portion treated of nearly 50 per cent, and an increase of the value of 
this fruit over the rest of 100 per cent. The loss from not having treated 
the other two-thirds was estimated at $2,500. The saving to the plum 
crop, and other small fruits, frequently amounts to the securing of a 
perfect crop where otherwise no yield whatever of sound fruit could be 
secured. An illustration, in the case of field insects, may also be given 
where, by the adoption of a system of rotation, in which oats was made 
to alternate with corn, the owner of a large farm in Indiana made a 
