422 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



ANURAPHIS HELICHRYSI KALT., A PEST OF PRUNE, 

 PLUM, AND RED CLOVER IN IDAHO 



By Ralph H. Smith, Entomologist, 

 Idaho Experiment Station, Moscow, Idaho. 



Anuraphis helichrysi Kalt. is the most important plant louse affect- 

 ing prune and plimi in Idaho. Injury has been common in both do- 

 mestic and commercial orchards during the past four years. Red clover 

 and garden asters, the most important simimer host plants, are fre- 

 quently very heavily infested. Injury to clover during the summer 

 of 1921 caused a marked reduction in the yield of seed in several fields 

 near Twin Falls while florists and housewives have experienced real 

 difficulty in successfully growing garden asters on account of this aphid. 



Historical. The species first came to the attention of the writer in 

 the spring of 1918 when on taking up work in Southern Idaho he found 

 the foliage of prune, plimi and peach to be infested with aphids to such 

 extent that the leaves of many trees either mostly fell off or remained 

 strongly curled thruout the summer. The aphid affecting peach was 

 identified as Myzus persicae Sulz. The species infesting prune and plimi 

 was identified by Dr. C. P. Gillette and later by Dr. A. C. Baker as Anur- 

 aphis helichrysi. Kaltenbach. 



The pest doubtless has been present in Idaho for many years. Ed- 

 mundson^ does not mention it among the orchard insects of Idaho but we 

 are led to believe that he and probably others have confused it with 

 Anurpahis cardui L. (A. pruni Koch) which ranks next to A. helichrysi 

 as an aphid pest of plimi,at least in the southern part of the state. We 

 have been able to find only two collections of aphids from prune and plimi 

 that were made in Idaho previous to 1918. One of these is a yet un- 

 determined species collected in 1910; the other, which is labeled merely 

 "ApJiis pruni on prune, collected 1911", is Anuraphis helichrysi Kalt. 



Seasonal Behavior. Migrant females and m^ales begin developing 

 on the summer host plants during the latter part of August at Twin Falls 

 (alt. 3700 ft.). They are found in fair abundance on foliage of prune 

 and plum by the 15th of September. The migrants and greenish to 

 reddish-brown oviparia feed preferably on the under surface of the leaves 

 and especially within the closely curled leaves that have been curled by 

 the spring generations. Eggs are deposited at the bases of buds and on the 

 bark of branches. Hatching takes place ven,' early while the buds of prune 



^Insect Pests of the Orchards and Gardens of Idaho and their Control. Idaho Exp. 

 Sta. Bui. 87. 1916. 



