624 



TfiE MOiTTHLY BtJLLETll^. 



GENERAL NOTES. 



THE PRUNE APHIS. 



(Aphis prunif olive Fitch.) 



The appearance of this aphid was recorded on page 569, volume II 

 of The Monthly Bulletin in June, 1913. Since this record the aphid 

 has been reported from many prune-growing sections of the Sacramento 

 Valley and has caused alarm and worry to some of the orchardists. The 

 louse is light green in color, and is covered with a rather thick coating 

 of fine white powder, which at once distinguishes it from all other lice 

 attacking the prune. It attacks the tips of the twigs and collects in 



Pig. 355. — Prune leaf covered with the prune aphis, Aphis prunifoliw Fitch. 



Sliglitly enlarged. (Original.) 



exceedingly large colonies, especially upon the under sides of leaves 

 which are slightly curled by their work. Figure 355 shows the actual 

 conditions on a single prune leaf taken from the Yolo orchard in Yolo 

 County on May 10, 1913. At that time the presence of the larvse of 

 syrphid flies and internal hymenopterous parasites were in sufficient 

 numbers to indicate that the pest would be subdued before it did any 

 great amount of damage. In a few sections, however, control measures 

 were found necessary, which consisted of the application of a tobacco 

 spray composed of nicotine sulphate in the proportions of 1 to 1500. 

 A coarse driven spray under high pressure is necessary to force the 

 liquid through the powdery waxy coating secreted by the insect.— E. 0. 

 EssiG. 



