No. 4.] FRUIT TEEES AND INSECT FOES. 



123 



fence, attack the unprotected trees of neighbors. Such a pro- 

 tection will not only keep out borers for several years before 

 it gives out, but will protect the trees in winter from the attacks 

 of mice and rabbits, while also permitting light and air to 

 reach this portion of the trunk. 



During the fall months the fruit grower frequently finds 

 certain parts of the limbs of his fruit trees more or less cov- 

 ered with a white wool, beneath which investigation shows 

 the presence of large numbers of small plant lice (Schizoneura 

 lanigera Haus.). These lice suck the sap from the tree, and 

 locate, if possible, where the bark has been broken or rubbed, 

 it being easier at such places to reach the sap than elsewhere. 

 This insect is not usually a serious pest in Massachusetts; but 

 as it also works on the roots and may do considerable injury 

 there, its presence on the branches is an indication that the 

 roots may also be suffering, and should be examined. To do 

 this, the soil should be carefully removed till enough of the 

 roots is exposed to determine their condition. If the lice are 

 present, the earth should be removed down to the upper roots 

 for a distance of two feet from the trunk in all directions, and 

 this area well saturated with 15 per cent kerosene emulsion. 

 The earth should then be put back, and the emulsion left to 

 work through the ground to the lice. 



In August and September caterpillars of various kinds feed 

 on the apple leaves, often in clusters, and are quite conspicu- 



Fig. 7. — Yellow-necked apple-tree caterpillar : a, caterpillar, 

 showing characteristic position when disturbed; b, adult 

 moth ; c, cluster of eggs, natural size ; d, side view of one 

 egg, much enlarged. 



ous because of their bright colors. One of these is the yellow- 

 necked apple-tree caterpillar (Datana ministra Dru). When 

 disturbed this caterpillar lifts both ends of its body at right 



