INSECTS INJURIOUS TO THE APPLE AND PEAR 639 



and become a light brown or dark green color on the upper leaf 

 surface and uniformly brown beneath/ looking something like 

 the work of the apple rust. The young fruit is sometimes attacked 

 on which small green pimples, which later make blister-like spots 

 or pock marks, are made toward the blossom ends, but which 

 do not seem to cause much damage. 



Control. The mites may be controlled by spraying with 

 10 per cent kerosene emulsion, miscible oils, or lime-sulfur wash 

 used the same as for the San Jose scale. Spraying should be 

 done in October or November as soon as possible after a majority 

 of the leaves have fallen, as many of the mites are still in the 

 pubescence of the young wood, where they are more easily de- 

 stroyed than when under the bud scales. In spring spray just 

 as the buds begin to break and show the tips of the young leaves; 

 spraying later than this will injure the foliage, and earlier spraying 

 is not as effective. By using lime-sulfur in the spring, the usual 

 treatment with Bordeaux mixture for diseases at that time is 

 unnecessary. Where infestation is serious both fall and spring 

 sprayings should be given; otherwise the fall spraying is the 

 better. The buds and new growth should be thoroughly drenched, 

 while the rough bark of the trunk and old limbs may be neglected 

 as far as the mites are concerned. Where pear trees are but 

 slightly infested, the spread of the pest may often be prevented 

 by simply pruning out and burning the infested twigs upon the 

 first appearance of injury. 



The Pear Psylla * 



Where the pear psylla is abundant, pear growers have come 

 to fear it next to the San Jose scale, and until recently owners 

 in eastern New York became so discouraged in their attempt to 

 control it that orchards were cut down. It is an old European 

 pest and was first noted in Connecticut in 1832, since when it has 

 spread southward to Maryland and Virginia and westward to 



* Psylla pyricola Foerst. Family Psyllidce. See M. V. Slingerland, 

 Bulletins 44 and 108, Cornell Univ. Agr. Exp. Sta.; C. L. Marlatt, Circular 

 7, Div. Ent., U. S. Dept. Agr. 



