AN APHIS ATTACK ON ROOTS OF PEACH-TREES, 21 



In many species of the true plant-lice, it is now well established that 

 there are two types of the same insect, the one inhabiting the roots, and 

 living there during the colder part of the year unwinged — the other 

 inhabiting the leaves and twigs throughout the spring and sum- 

 mer. This is notably the case with a small black aphis which injures, 

 and even destroys, the peach-trees of eastern Maryland, Delaware and 

 New Jersey. 



Remedial measures. — The following measures, substantially, were 

 recommended by me, to Mr. Blodget, as promising success in arresting 

 the attack of this root-aphis: 



Remove a portion of the surface soil from above the roots of the 

 young trees, and apply hot water of as high a temperature as experiment 

 would show could be borne by the trees without injuring them. This 

 should prove fatal to the aphides. 



A kerosene and soap emulsion, similarly applied, could hardly fail of 

 proving effectual, as also the Soluble Phenyle noticed in the First Re- 

 port on the Insects of New York, pp. 4S-50. Simply pulling up the in- 

 fested seedlings and burning them, cannot be relied upon to arrest such 

 an attack, if others are to be grown in the same ground. Numbers of 

 the insects would be left in the soil surrounding the roots, where, after 

 the removal of the peach roots, other food might be found affording 

 nourishment and providing for the continuance of the species. It was 

 formerly believed that the species of Aphides were confined to a single 

 food-plant. Dr. Fitch was of the opinion that A. cerasi pertained only 

 to the garden cherry, Cerasus vulgaris, and that each " of our native or 

 wild cherry trees [five species] have plant-lice peculiar to them which sel- 

 dom if ever fix themselves upon the foliage of the other kinds ; " yet the 

 A. cerasi {Myzus cerast) has since been found upon the plum and the 

 peach, and perhaps upon so different a food-plant as the Chrysanthemum, 

 Prof. Uhler having expressed the opinion that it may be identical with 

 Aphis chrysanthemi. If then, the attack upon the seedlings be not en- 

 tirely arrested by the measures above recommended, a new locality should 

 be selected for growing them, and the ground that they had occu- 

 pied treated with a liberal application of fresh gas-lime, which, when 

 washed in by rains, could be relied upon for killing the Aphides at the 

 moderate depth at which they would occur. 



When the roots of larger trees, which are too valuable to sacrifice, are 

 attacked by this insect, the method might be used which was found 

 highly successful in France for the destruction of the Phylloxera upon 

 the roots of grapevines, viz., the introduction of bisulphide of carbon 

 mto the soil by pouring a small quantity of it into a hole two or three 

 feet in depth, made in the ground by a pointed bar, confining it therein 

 by packing the ground over it so that in its gradual decomposition it 



