UNITED STATES DEPARTMENT OF AGRICULTURE 



| BULLETIN No. 535 i 



St-W^St* 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



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. Howard, Specialist. 



CONTENTS. 



Page. 



Introductory 1 



Descriptive 3 



Distribution in North America 5 



Origin and dissemination 6 



Review of literature 7 



Food plants 8 



Seasonal history 8 



Recent injury 12 



Natural enemies 13 



Associated insects 13 



Methods of control 13 



Summary 14 



Bibliography 15 



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 



Note. — 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 (Evergestis 

 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 



