UNITED STATES DEPARTMENT OF AGRICULTURE 



& BULLETIN No. 703 



r\ Fve^' Contribution from the Bureau of Entomology *^syt ji 



J^^'^^^U L- O. HOWARD, Chief ,tf\^"^W^w 



WASHINGTON, D. C. T November 20, 1918 



MISCELLANEOUS TRUCK-CROP INSECTS IN 

 LOUISIANA. 



I.— INSECTS INJURIOUS TO THE GLOBE ARTICHOKE IN 



LOUISIANA. 



By Thos. H. Jones, 



Entomological Assistant, Truck-Crop Insect Investigations. 



INTRODUCTION. 



Insect injury to the globe or burr artichoke {Cynara scolymus) 

 apparently has received little attention from American economic 

 entomologists. While the artichoke has not as yet attained the rank 

 of an important food plant in the United States, the demand for the 

 edible heads is increasing in the markets. The crop is grown in 

 Louisiana, and since the fall of 1914, when the writer was assigned 

 for work on truck-crop insects, in cooperation with the Louisiana 

 Experiment Stations, many growers have complained of insect in- 

 jury to the plants. 



The most serious damage to the globe artichoke in Louisiana is 

 caused by two species of plant-lice, or aphids, Myzus hraggii Gil- 

 lette and Aphis rumicis Linnaeus, both usually occurring in the same 

 field and being most numerous during the late winter and in the 

 spring. 



INJURY CAUSED BY THE ARTICHOKE APHIS, MYZUS BRAGGII. 



The artichoke aphis is the most common and, generally speaking, 

 the most injurious insect enemy of the globe artichoke in Louisiana. 

 It occurs in great abundance on the under sides of the leaves and 

 its green color harmonizes with that of the leaf. In cases of severe 

 infestation its presence brings about a condition such as that de- 

 scribed in the following letter sent in by a correspondent in Eapides 

 Parish: "Please let me know what to do for burr artichoke plants 

 attacked by a dark smut which attracts large flies and bees. I had 



1 



58681°— 18— Bull. 703 1 



