2 BULLETIN" 703, U. S. DEPARTMENT OF AGRICULTURE. 



the same disease attack my plants last year about the same time. 

 Most of the plants recovered, but seem to have lost vitality and did 

 not bear fruit as early or as plentifully as in former years." The 

 presence of the "dark smut," the flies, and the bees referred to is 

 accounted for by the " honeydew " from the aphids, and in fields 

 where the Argentine ant (Iridomyrmex Twmilis Mayr) is present, 

 this obnoxious pest attends the aphids. Besides this complaint from 

 Rapides Parish, there are also at hand records of Myzus hraggii 

 injuring globe artichoke in East Baton Rouge, Ascension, Iberville, 

 Terrebonne, and Plaquemines Parishes. 1 



Myzus hraggii also infests the yellow thistle (Cirsium* horridulum) 

 which is a common weed in Louisiana. (See PL I, fig. 1.) This plant 

 is closely related, botanically, to the globe artichoke, so that the pres- 

 ence of the same species of insects on the two plants is to be ex- 

 pected. Prof. C. P. Gillette, who described Myzus hraggii 2 from 

 Colorado in 1908, and who has determined material sent to him from 

 Louisiana, states that at Fort Collins, Colo., it is found on Canada 

 thistle {Cirsium arvense) during the latter part of the summer and 

 early fall, and that "the winter hosts are the Russian olive, Hip- 

 pohaes rhamnoides, and Shepherdia arvensis." 3 



ENEMIES OF THE ARTICHOKE APHIS. 



While no internal parasite has been found attacking this aphis, a 

 number of predacious insect enemies have been observed. These in- 

 clude the larvse of the syrphid flies Allograpta ohliqua Say and Syr- 

 phus americanus Weidemann, the larvse and adults of the coccinellid 

 or ladybird beetles Scymnus puncticollis LeConte, Scymnus termi- 

 natus Say, Hippodamia convergens Guerin, and Cycloneda sanguinea 

 Linnaeus, as well as the larvae of a chrysopid and a hemerobiid, both 

 undetermined. The coccinellid beetle Megilla maculata DeGeer and 

 the predacious bug Triphleps insidiosus Say have been taken on 

 globe artichoke infested with Myzus hraggii and probably feed upon 

 this aphis. The aphid is attacked by a fungus, which Dr. A. T. 

 Speare, Bureau of Entomology, has determined as Entomophthora 

 fresenii Nowakowski. At Baton Rouge Scymnus pwicticollis ap- 

 pears to be its most efficient enemy. 



INJURY CAUSED BY THE BEAN APHIS, APHIS RUMICIS. 



While not as common on globe artichoke in Louisiana as Myzus 

 hraggii, this aphis is more difficult to control by spraying than is 

 the latter species, largely because of the fact that infested leaves 



i Dr y. H. Chittenden states that he has collected the species on globe artichoke at 

 Washington, D. C. 



2 Gillette, C. P. New Species of Colorado Aphididae, with Notes upon their 

 Life Habits' In Can. Ent, v. 40, no. 1, p. 17-20, pi. 1. 1908. 



s Gillette, C. P. Confusion of Rhopalosiphum hippohaes Koch, and Myzus 

 braggii Gillette. In Jour. Econ. Ent., v. 8, no. 3, p. 375-379, pi. 17, 18. 1915. 



