a 
The More Important Apple Insects. 59 
fall, with consequent damage to the tree «nd fruit crop. The fruit itself is 
sometimes injured, as shown in figure 119. The pear is more generally infested 
by this species than the apple, and the service-berry and other host plants are 
also attacked. While not a pest of first-class importance to apple growers gen- 
erally, nevertheless its injuries in some localities must be provided against. 
Damage to the apple has been especially pronounced in New England, in por- 
tions of New York, and more recently in certain apple-growing districts in 
Washington. Recently apple leaves infested by this mite have come from Mis- 
sissippi. The pear-leaf blister-mite is of European origin and was probably 
introduced into this country many years ago on nursery stock. It is now 
widely distributed in the United States wherever pears are grown. 
The winter is passed in the adult stage beneath the bud scales. The adults 
(fig. 120) are very small, elongate, whitish, and measure about one one hundred 
and twenty-fifth of an inch in length. In 
the spring, when the leaves are unfolding. 
the mites enter through the lower epider- 
mis, and their activities soon bring about 
the blisterlike galls in which they live and 
multiply. After reaching maturity, the 
mites desert the old galls, make new ones, 
and produce a new generation. A succes- 
sion of generations is thus developed each 
season up to the approach of cold weather, 
when the mites migrate to the bud scales, 
beneath which they hibernate. 
If it is necessary to spray the orchard 
for the San Jose seale, no special treat- 
ment for the pear-leaf blister-mite will be 
required, It is readily controlled by the 
use of commercial lime-sulphur (32° 
Baumé) 62 gallons w:th water sufficient to Fre. 119.—Injury to fruit by pear- 
make-a total of 50 gallons, as employed in eS 
the control of the San Jose scale. If the application is for the mite only, a 
somewhat weaker spray will answer, using 53 gallons of the concentrate and 
sufficient water te make 50 gallons. The application may be made after the 
leaves have dropped in the fall, or in the spring before the buds have swollen to 
any extent. Miscible oils and kerosene emulsion of standard dormant tree 
strengths may also be used effectively. 
RED SPIDER.“ 
The injury to the apple by the red spider results from the sucking out of plant 
juices, giving the foliage an unhealthy, mottled appearance. If the attack is 
severe, the injury may be quite important, resulting in 
defoliation of the trees and interference with tire proper 
development of the fruit and fruit buds. This mite is 
I'kely to be most troublesome during dry sezsons, and in 
arid or semiarid regions it is a pest of importance. Its 
Adults of injuries, however, are often confused with those of the 
Hic. 120. 
pear-leaf blister ¢joyver mite (p. 60). The red spider is widely dissemi- 
mite. Greatly en- 
larged. nated throughout the United States and attacks the apple 
and many other deciduous fruits. cultivated flowers, vines, 
truck crops, etc. It is preeminently a pest in greenhouses and requires constant 
vigilance on the part of growers to keep it in check. ; 
46 Tetranychus telarius Linnaeus. 
