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Badly infested nursery stock should be destroyed, since it would be 

 worth little even with the aphides removed. Slightly infested stock can 

 be easily freed of the aphides at the time of its removal from the nursery 

 rows. The soil should be dislodged and the roots pruned, and in 

 batches of a dozen or so the roots and lower portion of the trunk should 

 be immersed for a few seconds in water kept at a temperature of 130° 

 to 150° F. A strong soap solution similarly heated or a tifteen times 

 diluted kerosene emulsion will give somewhat greater penetration and 

 be more effective, although the water alone at the temperature named 

 should destroy the insects. This treatment is so simple and inexpensive 

 that it should always be insisted upon by the purchaser if there be any 

 indication of the presence of this insect, and stock exhibiting much 

 damage should be refused altogether. 



After planting, if the trees be kept in vigorous growing condition by 

 careful cultivation and, if necessary, proper fertilizing, damage from the 

 aphides is much less apt to occur, and the principal danger period, 

 namely, the first two or three years after planting in the orchard, will 

 pass in safety. The value, as a means of protection, of thorough culti- 

 vation and good care of young orchards can not be too strongly 

 insisted upon. Vigorous growing trees have a decided power of resist- 

 ance and are able to sustain with comparatively little damage the 

 presence of the root-aphides, while illy-cultivated and neglected orchards 

 are especially liable to injury. 



The woolly aphis is subject to the attacks of a number of natural 

 enemies, including the parasitic chalcis tiy, Aphelinus niali Haldemann, 

 and the larva of a sjTphus fly, Plpiza radicnm Walsh and Riley, and 

 also the larva and adult of several species of ladybirds, the larvae of 

 lace-wing flies, and spiders, etc. In the East a very small brown species 

 of ladybird, Sci/ninus cervicalis Muls., is often present in some numbers, 

 and the common nine-spotted ladybird, Coccinella 9-notata Hbst., is also 

 an active enemy of the wooll}^ aphis. The nine-spotted ladybird has been 

 used very successfully in California, on the authority of Mr. Ellwood 

 Cooper, to rid trees of root-aphides, this being effected by colonizing the 

 larvse of the ladybird at the base of the infested tree. All the para- 

 sites mentioned do much to keep the root-aphides in check, and in the 

 case of old well-established trees are in most instances a sufficient pro- 

 tection, but in the case of young trees and nursery stock, where the 

 damage from the aphis is much more rapid and serious, the use of the 

 direct remedies outlined should not be neglected, and particularly should 

 I he nursery treatment be insisted upon. 



Approved : 



James Wilson, 



Secreianj of Agriculfure. 



Washington, D. C, June 23, 1908. 



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