78 



pasturing heavily in autumn, and possibly bj- mechanical devices 

 for capturing the nymphs or adults. The spread of the insect should 

 be prevented by care in the disposal of timothy hay moved to a distance. 

 No hay from an infested district should be allowed to be scattered in 

 or near meadows in localities where the insect is not already present. 

 Natural enemies consist, so far as at present known, of spiders, a 

 predaceous damsel bug {Reduviol us ferns), a Tachinid fly {Phorantha 

 occidentis) and another undetermined species, as well as a fungus. 

 Entomophthora sp. 



Jones (T. H.). Miscellaneous Truck-Crop Insects in Louisiana. 

 1. Insects injurious to the Globe Artichoke in Louisiana. 2. The 

 Granulated Cutworm, an Important Enemy of Vegetable Crops in 

 Louisiana. 3. Experiments in Controlling the Tomato Fruit-worm 

 with Arsenicals.— C7./S. Dept. Agric, Washington, D.C., Bull, 

 no. 703, 20th November 1918, 19 pp., 5 figs, 5 plates. 



The Aphids, Myzus braggi, Gill., and Aphis nimicis, L., are the insects 

 that cause the most serious damage to the globe artichoke {Cynara 

 scolymus) in Louisiana. M. hraggi (artichoke aphis) occurs in large 

 numbers on the imder-side of the leaves. In fields where Iridomyrmex 

 humilis, Mayr (Argentine ant) is present, this pest attends the Aphids. 

 A. rumicis (bean aphis), while not so common on artichoke as M. h'aggi, 

 is more difficult to control by spraying owing to the distortion of the 

 leaves caused by its attack. Other plants infested by M. hraggi are 

 Cirsium horrididum (yellow thistle), a common weed in Louisiana, 

 C. arvense (Canada thistle) on which it is found in Canada during the 

 latter part of summer and early autumn, while the winter hosts are 

 HippopJiaes rhamnoides (Russian olive) and Shepherdia arvensis. 



No internal parasite has been found attacking this Aphid, but it 

 has many predaceous enemies, including the Syrphid flies, Allograpta 

 ohliqua, Say, and Syrphas americanus, Wied., the larvae and adults 

 of the Coccinellid beetles, Scymnus puncticollis, Lee, S. terminatus, 

 Say, Hippodamia convergens, Guer., and Cycloneda sanguinea, L., as 

 well as the larvae of a Chrysopid and a Hemerobiid, both undetermined. 

 Another Coccinellid, Megilla ?nacidata, DeG., and the predaceous 

 bug, Triphleps insidiosus. Say, have been taken on globe artichoke 

 infested with 31. braggi, and probably feed on this aphis, which is 

 also attacked by a fungus, Entomophthora fresenii. At Baton Rouge 

 S. puncticollis appears to be its most efficient enemy. 



During 1917 both these Aphids were satisfactorily controlled by 

 spraying with 1 part by weight of nicotine solution (containing 40 per 

 cent, of nicotine sulphate) to 1,000 parts of water, with laundry soap 

 (standard, non-caustic type) added at the rate of 1 lb. to 25 U.S. gals, 

 water. The plants were sprayed 7 times between 31st January and 

 26th May inclusive, more frequently than would have been necessary 

 had not the presence of the Argentine ant as well as of unsprayed rows 

 acted as a source of reinfestation. Pickings of edible heads from 

 11th May to 29th June showed an average of nearly 5 heads from 

 each sprayed plant, and of 1 from each unsprayed plant, while the 

 difference in growth of the plants was very noticeable. Sprajnng should 

 be begun while the plants are quite young and the Aphids few, partly 



