THE PEAR SLUG 159 



the leaf, giving it a peculiar and very characteristic appearance. 

 In serious cases, however, the most of the leaf is affected and 

 sometimes both leaves and fruit may drop as a result of the 

 injury to the leaves. The fruit is itself also attacked, though 

 much less commonly, and the injury is less severe and much 

 less conspicuous. 



The principal injury comes through the interference with 

 the functions of the leaf. The mites remain in the leaves until 

 autumn, when they seek the buds and work in under the outer 

 scales for the winter. 



The most convenient treatment is to spray with lime-sulfur 

 in the early spring. This catches them in their winter quarters 

 among the bud scales. Any of the forms of this wash which 

 are used for the San Jose scale will be effective, and fortunately 

 one application is usually all that is needed for both pests. In 

 the event of a very serious attack Professor Parrott of New 

 York, who has carefully investigated the blister mite, recom- 

 mends two applications, one in the autumn and one in the 

 spring, using kerosene emulsion diluted with five parts of 

 water. The autumn application is likely to be most effective, 

 since the mites have not yet secreted themselves in the bud 

 scales. This double treatment, however, is rarely necessary. 

 The mite has seldom been serious in orchards which are care- 

 fully sprayed for San Jose scale each year, while it is often 

 seen both in neglected orchards and in those where the spraying 

 is done carelessly. 



The Pear Slug. The foliage of the pear, plum, quince and 

 cherry is likely to be attacked by a shiny, olive-green little slug 

 with a brownish head. Frequently the first intimation one has 

 of any trouble is to notice that some trees in the orchard are 

 turning brown as though from the effects of dry weather. A 

 closer examination will show these little slugs scattered over the 

 upper surface of the leaves. They eat out the tissue of the 

 leaves till only the ribs and the epidermis of the lower surface 

 remain. The leaves turn as brown as in winter and are later 

 sometimes replaced by a new crop. The slugs spend the winter as 

 larvae in the soil and emerge in late spring or early summer. 



