l6 MAINE AGRICULTURAL EXPERIMENT STATION, 



only one of the two hosts necessary for the life cycle of a 

 migratory aphid planted, where the pest is a serious one. 



It is desirable that data concerning the relative susceptibility 

 of different varieties of apple should be accumulated with a view 

 to using the more resistant for root stock, if otherwise practi- 

 cable. 



In dealing with infested apple trees the aphid masses on trunk 

 and branch present no especial difficulty, and can be very readily 

 exterminated by the use of any of the washes recommended for 

 plantlice, such as tobacco decoction, kerosene emulsion, a strong 

 soap wash, the only care necessary being to see that the wash 

 is put on with sufficient force and thoroughness to penetrate 

 the covering and protecting cottony secretion. If the wash be 

 applied warm, its penetration will be considerably increased. 



An August spray to kill out colonies before the migrants fly 

 and the hibernating young are produced is particularly desirable. 



The much more important root feeders, however are more 

 difficult to reach and exterminate. The common recommenda- 

 tions are of applications of strong soap or tobacco washes to the 

 soil about the crown, or soot, ashes, or tobacco dust buried about 

 the roots ; also similarly employed are lime and gas-lime. 



Badly infested nursery stock should be destroyed, since it 

 would be worth little even with the aphids removed. 



Some nurseries are said to make a practice of "puddling" 

 roots of infested stock, that is packing mud about the roots to 

 conceal their condition. Before purchasing puddled nursery 

 stock, the buyer should insist that the mud be washed off 

 thoroughly so that- the roots are exposed for inspection. 



Proper cultural methods can hardly be overestimated in their 

 value as a protection of young trees, as neglected orchards not 

 only suffer heavily but serve as a breeding ground dangerous to 

 the neighboring trees. 



AA. INJURING THE FOLIAGE. 



(Divisions a, b, c, d, and e). 

 a. Plantlice, small greenish, blackish or reddish lice-like sucking 

 insects. 

 Greenish plantlice in colonies causing leaf curl. (fig. 33). 



Green apple-aphid. Page 20. 



