Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. Vv June 28, 1917 
THE HORSE-RADISH FLEA-BEETLE: ITS LIFE 
HISTORY AND DISTRIBUTION. 
By F. H. CHITTENDEN, Entomologist in Charge of Truck Crop and Stored 
Product Insect Investigations, and NEALE F. Howarp, Specialist. 
CONTENTS. 
Page. Page 
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ID GSO OUT CLE Seite ea bee ote ero et Ee ee Si peNaturalven emilee pee ere eee Sal Nn 13 
Distribution in North America.............. Oil PeASSOCIA LEC IM SC CLS eee seem ne 13 
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ReviewsOrlteraturezss22 2 se2ce see 222 (Gael oS ULTTIITD Tey; Seater ola 14 
PHO ANG Sree ener en cee a ans Sues BD LTO Sra hiya eae een tt teh ele 15 
SCHscial! TOMSKO A Gsccosnaadaseseueerueeesess 8 
INTRODUCTORY. 
Nearly every year there is brought to this country some insect 
immigrant, and frequently, in the course of time, these immigrants 
prove to be pests. As a rule, they are introduced through the large 
seaports, particularly Boston, New York, New Orleans, and San 
Francisco, from which points they spread westward, northward, or 
southward, and less frequently eastward. Occasionally such an in- 
sect is carried by commerce beyond the coasts and makes its first 
appearance inland. This happened in the case of the insect to which 
the senior author has given the name of the horse-radish flea-beetle 
(fig. 1) and which is known zoologically as Phyllotreta armoraciae 
Nore.—Horse-radish is widely cultivated in the United States and especially where 
the horse-radish flea-beetle is now most injurious. The farm value of horse-radish is 
not far from $400,000 per annum, considering its growth for home use.’ Two other 
insects than the horse-radish flea-beetle are especially attracted to it, the horse-radish 
webworm (Plutella armoracia Busck) and the horse-radish caterpillar (Hvergestis 
straminalis Hiibn.). Neither of these is of any importance, but in the southern range of 
growth of horse-radish the harlequin cabbage bug is a most destructive pest, seeming to 
prefer this plant to other crucifers. ‘The horse-radish flea-beetle will continue to spread 
and soon become a dangerous pest unless growers practice methods of control. 
81307°—17 
