THE NATIONAL NURSERYMAN 
161 
THE LEAF BLISTER MITE OF PEAR AND APPLE 
Red or green blister-like spots appearing in the early 
spring on the foliage of the apple and pear are usually 
due to the leaf blister mite. This is not an insect hut a 
small animal, invisible to the unaided eye, which attacks 
standard varieties of pear and apple trees and often in¬ 
flicts serious damage. Where trees are seriously in¬ 
fested, the premature fall of both fruit and leaves may 
result. In such cases a special application of lime-sul¬ 
phur wash or other spray may he necessary. Ordinarily 
however, the regular orchard spraying is sufficient to 
control the mite. Badly-infested branches of the pear 
trees may be cut off and burned. Care should he taken 
not to confuse the work of the mite with the leaf-spot 
disease or the results of heavy spraying. 
Describing the leaf blister mite, showing how it may 
be recognized, and giving methods for its control, the U. 
S. Department of Agriculture has issued a new Farmers’ 
Bulletin, No. 722, “The Leaf Blister Mite of Pear and 
Apple,” by A. L. Quaintance. The leaf blister mite 
passes the winter beneath the bud scales. There it 
waits for the opening of the buds and attacks the young 
leaves as soon as they push out in the spring. The tiny 
animals bore small holes from the underside of the leaves 
into the interior where they lay their eggs. This causes 
the small, pimple-like galls on the upper surface of the 
leaves. The spots later increase in size, sometimes to 
one-eighth of an inch, and on the pear tree are red and 
often brilliantly colored as they grow. In the case of 
the apple, the eruptions lack the more brilliant coloring 
and are found more along the margin of the leaf. In 
both cases the spots finally turn brown or black, and if 
the pest is abundant the leaves become ruptured and 
wrinkled. 
More than 250 varieties of apples are attacked by the 
mite, injury being especially severe on some well-known 
commercial sorts, such as the Ben Davis, the King, Bald¬ 
win. Rhode Island Greening, and the Williams Favorite. 
Where orchards are seriously infested, as has been 
noted in New York State, lime-sulplmr washes give ex¬ 
cellent results. They avoid the injurious effects upon 
fruit buds which sometimes result from the use of oil 
sprays. The wash should be applied thoroughly, coat¬ 
ing the twigs and branches. 
A standard solution of kerosene emulsion may also be 
used. The stock solution should be diluted with live 
parts of water for spraying purposes. One application 
should be given in the late fall, as soon as most of the 
leaves have fallen, and another in the following spring, 
before the trees put out foliage. If it is possible to give 
only one treatment, the sprays should be used in the fall. 
At this time many of the mites have not yet gone to the 
bud scales, but occur in the down covering the young 
wood, and hence are more easily killed. 
DEER DIGGING 
The thoroughly practical man as well as the scientific, 
agree on the great value of deep digging. To such men, 
the present talk about worn out and abandoned farms and 
failing food supply is all nonsense. The remedy is a 
simple one. There is enough land in the United States 
to support many times its population, and then to spare, 
if properly cultivated. Gardeners of the Old School 
claim a man owning one acre of ground has really two, if 
he cares to plow and cultivate it deep enough. 
Land is very much like a banking institution. You 
can draw interest and gains according to the amount of 
intelligent labor and fertilizer you invest,—usually with 
compound interest,—but if no deposits are made, the land 
or bank soon becomes insolvent. There is plenty of land 
in Europe, still producing good crops, that has been in cul¬ 
tivation since long before America was discovered, and 
worn out land is really a disgrace, showing bad manage¬ 
ment rather than fault of the ground itself. 
The one prime necessity for keeping the ground in good 
heart, and so capable of producing good crops, is deep 
digging or plowing, as the case might be,—especially on 
heavy lands. However good the top spit of soil may be, 
if it is underlaid with undisturbed hard-pan, it is not 
likely to produce good crops. It must be remembered 
that plants can only take up the foods necessary to their 
growth while in solution. In other words, they cannot 
eat or absorb solids, so there must constantly be sufficient 
moisture in the soil to dissolve the plant foods that may 
be in contact with the roots. 
A shallow soil, underlaid with hard-pan, dries out in a 
very short period. If the same kind of ground is dug 
deeply or sub-soil plowed, it will be much more retentive 
of moisture, thus conserving it during the dry weather, as 
it acts like a sponge, holding it rather than allowing the 
moisture to run off as it does through the myriad little 
channels that are always formed in undisturbed soil. 
Sandy soils are least retentive of moisture, especially 
if underlaid with a gravelly sub-soil. Such soils are 
loose in texture, and deep digging is not so essential; but 
an abundant supply of organic matter in the form ot 
stable manure or green manure crops, is always advis¬ 
able. 
The loamy soils and retentive clays are the ones it is 
most important to dig deeply. R would surprise many 
gardeners that have this class of land, it they would 
deeply trench their ground in the tall, throwing it up in 
ridges so as to allow the frost to get down deeply and dis¬ 
integrate the soil. It would produce much better crops, 
and be much easier to work, and would yearly improve 
rather than deteriorate under such treatment. 
