UNITED STATES DEPARTMENT OF AGRICULTURE 



yiy DEPARTMENT BULLETIN No. 1336 CD 



Washington, D. C. 



V 



September, 1925 



BIOLOGICAL STUDIES OF THE GREEN CLOVER WORM 



By Chas. C. Hill, Assistant Entomologist, Cereal and Forage Insect Investiga- 

 tions, Bureau of Entomology 



CONTENTS 



Page 



Introduction 1 



Systematic history 1 



Synonymy 2 



Geographical distribution 2 



Food plants ___ 2 



Page 



Description of stages 3 



Life history and habits 8 



Seasonal history 14 



Natural enemies 16 



Literature cited _ 19 



INTRODUCTION » 



The green clover worm, Plathypena scabra Fabr., has long been 

 recognized as a pest of wide distribution and injurious to various 

 crops. In 1914 and 1915 it occurred in abundance in alfalfa fields 

 in the vicinity of Nashville, Tenn., and studies on its life history 

 were commenced by the writer at that time. During the summer of 

 1919 a general outbreak of this pest on different crops occurred of 

 sufficient severity to attract the attention of agriculturists through- 

 out a large portion of the East. A popular account with recom- 

 mendations lor control as an alfalfa pest, Dased on studies conducted 

 by the writer in Tennessee, was published (-5) 2 in 1918. The present 

 bulletin embodies technical details regarding the biology of this insect 

 which necessarily were omitted in the popular account. 



SYSTEMATIC HISTORY 



Owing to sexual dimorphism in this species, the sexes were origi- 

 nally considered as distinct species, a mistake which was not dis- 

 covered until 1873, when Lintner (7), through study of his own col- 

 lection and those of others, found that the species, then known as 

 Hypena scabra Fabr. and Hypena erectalis Guen., were each repre- 

 sented in collections by a single sex. He communicated this obser- 

 vation to Grote, who substantiated it by further examinations; and 

 ktt;r in the year both men published the fact that erectalis Guenee 

 was merely the female form of scabra Fabricius, of which heretofore 

 only the male form had been known. Grote (3), in his paper, erected 

 for the species the genus Plathypena. 



'The author expresses his appreciation of liclplul :n^i'c:;l iuii;, irceivi'd fiom ( Ico. ( I. \iiislic, mihIi-i \vlio:<« 

 direction wort on fliis Insect was first Btarted al WashvUle, Tenn., and ><> ''ail Relhrlch for Ruldancfl in 

 tiii: construction of papa] and seta! charts. 



; Reference Is made by number (italics) to " Mt< rfttUre cited/' p. 19, 



