29 



THE GREEN APHIS OF THE APPLE. 



Description and habits. — In winter a sharp inspection of the apple 

 trees in the orchard will usually reveal the fact that some of them 

 have their twigs literally covered with shiny black oval eggs, large 

 enough to be seen easily with the naked eye. About the time the 

 leaves develop in the spring these eggs hatch, and, curiously enough, all 

 of them give rise to females. These females are peculiar in that after 

 a few days they give birth to living young, and this without having 

 been fertilized. They are, therefore, called agamic or virgin repro 

 ducing females. Similar liroods follow each other quickly thi'oughout 

 the summer, and reproduce with wonderful rapidity. All of these 

 summer broods, like the first, are composed of agamic f amales. Some 

 of the broods are wholly or in part winged, and such spread the pest 

 to other trees or orchards. As cold weather approaches there is pro- 

 duced a brood of perfect males and females. The latter lay the fer- 

 tilized winter eggs by which the life of the insect is tided over to the 

 following spring. 



This insfect varies in its abundance from year to year, and some 

 places are much more trouliled with it than others. In most orchards 

 only a small portion of the trees are attacked, the insect seeming to 

 pick out the weak or sickly ones especially. The damage done is not 

 very great, but the attacked trees are unsightly on account of their 

 distorted leaves and the dirtj^-black appearance caused by the excre- 

 tions of the aphides. 



Natural enemies. — On an aphis-infested tree are always found many 

 other insects. The lady birds and lace-wing flies feed on the aphides 

 and destroy great numbers of them. Ants are attracted and feed on 

 the honey dew which the aphides excrete from two tube-like processes 

 on their backs. It is a popular mistake that the ant destroys the green 

 aphis. This is not the case. Besides the above, many other insects 

 are found. Some are parasites of the aphides, but most of them are 

 attracted b}^ the honey dew. 



Remedies. — It pays to search out in the winter the trees which are cov- 

 ered with eggs, and either to cut off the infested twigs or to spray the 

 tree with sulphur-salt-lime, which kills the eggs. It does not pay to 

 winter-spray a whole orchard for this insect, as is sometimes done. 



Perhaps the most satisfactory method of controlling this insect is to 

 spray with kerosene emulsion after the insects appear and before the 

 leaves curl up from their attacks. It may be necessary to spray sev- 

 eral times during the summer. 



The same method is the best one for combating other species of 

 aphis which attack trees. 



