No. 6. DEPARTMENT OF AGRICULTURE. 163 



The Margined blister beetle, Epicauta marginata, was injurious 

 in many places to truck crops, flowers, etc., and was sent to us by 

 various^ correspondents. ^Miile it is alarming to observe it at the 

 time of its appearance, it does not remain long, and can, without 

 great difficulty, be driven away from the premises or destroyed by 

 using bunches of fine whips, vigorously applied. 



The Pear leaf blister mite, Eriophyes pijri, was reported from a 

 number of counties infesting the fruit and leaves of pear and apple, 

 especially from the northern part of the State. It was destructive 

 as far south as Mechanicsburg, Cumberland county, Pennsylvania. 

 This is becoming more and more destructive in this Commonwealth. 

 It does not appear to be as well known as it should be, and, con- 

 sequently, it is not recognized. The mite itself is too small to be 

 seen plainly with the unaided eye, but it makes black, sooty blotches 

 in the leaves of apple and pear, and these are quite distinct and 

 conspicuous. The tissue of the foliage is seriously injured, and the 

 leaves fail to perform their full normal functions and drop soon, 

 i^ ortunately, our tree growers are learning more and more to spray 

 during the" dormant season with strong lime-sulfur solution, and 

 those who do this are keeping the Blister mite in check. It appears 

 that this pest passes the winter beneath the bud scales on the trees, 

 and is destroyed by a dormant spraying such as is applied for scale 

 insects. The following circular was sent out from this office: 



Leaf Blister-Mites. The Blister-miies are small white, or pinkish- 

 white mites which produce open galls or blisters, looking like blotches 

 of soot on the under surface of leaves, fruits and fruit stems of 

 apple and pear. They spend the winter under the scales of the buds. 

 As soon as the leaves unfold in the spring they leave their winter 

 quarters and enter the stomata, first on the young leaves near the 

 base of the growing bud, spreading to the leaves toward the end 

 of the twig as the season advances. The eggs are deposited in the 

 tissue of the leaves some time in April and early May. The young 

 mites hatching from these eggs burrow through the epidermis of 

 the under side of the leaf, and feed upon tire tissues in the interior, 

 and this irritation produces a sooty thinning of the leaf, which is 

 known as the gall or blister. Other eggs are deposited throughout 

 the season within the galls, and the young mites after hatching 

 tunnel in all directions, thus enlarging the galls. Through an open- 

 ing in the under surface the mature rrrites emerge and pass to other 

 localities, where they form new galls. There are numerous genera- 

 tions throughout the season, as they breed for a period of about 

 six months. In October the adult mites seek shelter for the winter 

 in the buds. 



The injury from these pests first manifests itself by small green, 

 red, or yellow patches or pimples which enlarge, run together, and 

 form irregular dead areas, turning brown and dark later in the 

 season. Severely infested leaves lose their fresh green color, ac- 

 quire a variegated appearance, and drop from the tree. The affected 

 fruits are either destroyed, or, if they recover from the early attacks, 

 become stunted, and develop into fruit of poor quality. 



Treatment: Spray infested trees in the fall as soon as the leaves 

 have fallen from the trees, and again in the spring, thoroughly, with 

 one of the following materials: 



