380 



Insect Pests. 



Damson plantations often suffer most severely from this blight. 

 A good show of blossom may be seen, and by June scarcely a fruitlet 

 or leaf will be on the trees. Plums of all kinds and greengages suffer 

 nearly as severely. The same species may be seen on peach, apricot, 

 apple and, according to Buckton (1), on the aster. It is subject to 

 considerable variation in size and colour and probably occurs on 

 other plants, amongst which have been mentioned chrysanthemums 

 and gooseberry. Wild prunes afford a constant means of invasion 

 of our plantations. This species must not be confused with the Hop- 

 Damson Aphis (Phorodon humuli var. malaheb), easily told by the 

 frontal tubercles, which are absent in this species. Numerous com- 

 plaints have been received from the "VVhimple area in Devonshire (3), 



\A. V. I), liintoul. 

 FIG. 251. PLUM LEAVES CURLED BY Aphis pruni. 



as well as Worcestershire, Kent, Middlesex, Surrey, Hampshire, 

 Hertfordshire and Essex. 



LIFE-HISTORY AND HABITS. 



This aphis first makes its appearance in the very early spring, 

 when we observe small, dark green lice here and there on the shoots. 

 These have come from eggs that have remained all the winter upon 

 the plum trees. These lice grow into the wingless viviparous 

 females, large aphides, varying in hue from dull purple to olive- 

 brown. 



These apterous females soon commence to produce living young, 

 which rapidly mature and produce other young. The young pro- 



