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Webster (R. L.). The Box Elder Aphid {Chaitojihorus negundinis, 

 Thomas.) — Iowa State CoU. Agric. Expt. Sta., Ames, Bull. no. 173, 

 October 1917,pp. 95-l]9, 12 figs. [Received llthFebruary 1918.] 



Chaitophorus negundiriis (box elder aphis) is abundant on box 

 elder (Negtmdo aceroides), but has not been recorded from any other 

 trees except adjacent catalpas. Oviposition occurs in October, the 

 insect hibernating in the egg-stage. The usual life-cycle is varied 

 by the occurrence of a dimorphic form during the summer, consisting 

 of minute, flat, apterous individuals that remain inactive on the 

 leaves from June till September, when they moult and become active 

 forms. 



Control measures directed against the egg-stage consist in spraying 

 with tobacco extracts, a solution of Blackleaf 40, 1 part in 500 parts 

 of w^ater, being reliable and effective. The' eggs of C. negvnddnis are 

 said to be more easily killed than those of any other sj)ecies. Spraying 

 is best performed in May or Sei3tember, but is useless against the 

 dimorphic forms, which lie too flat on the upper and under-surfaces of 

 the leaves to be attacked. Kerosene emulsion, consisting of kerosene 

 2 U.S. gals., hard soap ^ lb. (or soft soap 1 lb.), and water 1 U.S. gal., 

 diluted for use in the proportion of 1 part stock solution to 9 parts 

 water, has given good results, and spraying with whale-oil soap solution, 

 1 lb. in 10 U.S. gals, water, is also an effective measure. 



In view of the fact that box elder is not a very desirable tree, the 

 simplest way to destroy this Aphid is to cut down the trees that 

 harbour them, replacing them by permanent shade-trees such as 

 elms or maples. 



The species is held in check by several natural enemies, the chief 

 being the larvae of the Syrphid flies, Allograpta obliqva, Say, and 

 Syrpkus americanus, Wied. ; an Agromyzid larva, Leucopis sp. near 

 L. griseola, Fall. ; a Cecidompd larva, Aphidoletes sp. ; the Cocci- 

 nelhds, Hippodamia convergens, Guer., Cycloneda sanguinea, L., Adalia 

 biptmctata, L., and the larvae of Scymnus americanus; the bugs, 

 Triphleps insidiosus, Say, and Plagiog?iathus annulatus, Uhler ; the 

 predaceous mite, Rhyncholophus pilosus ; the Hymenopterous para- 

 sites, Praon coloradensis, Ashm., and Aphidius polygonaphis, Fitch; 

 and three Chrysopids reared from larvae, Chrysopa nigricornis, Burm., 

 C. plorabimda, Fitch, and C. ocidata, Say. 



Parrott (P. J.) & Fulton (B. B.). The Cabbage Aphis.— iV^ew York 

 Agric. Expt. Sta., Geneva, Circ. no. 30, 15th June ] 914, 4 pp., 

 2 plates, 1 fig. [Received 11th February 1918.] 



The damage caused by Aphis brassicae, L. (cabbage aphis) may be 

 greatly reduced, if not prevented, by timely spraying. The eggs are 

 deposited during October and the beginning of November in depressions 

 of the under-surfaces of the leaves. They hatch in spring, usually 

 dm'ing April, giving rise to females that reproduce pai-thenogenetically. 

 Winged females appear at varying periods, spreading the infestation, 

 and in autumn the sexual forms appear, depositing eggs and completing 

 the life- cycle. 



The plants should be sprayed before the leaves are appreciably 

 curled, with a solution of soap, 6-8 lb. in 50 U.S. gals, water or with 

 Black leaf 40, | pint, soap 3-5 lb., water 100 U.S. gals. The liquid 



