SB 

 818 

 C578 

 ENT 



No. 43, Second Series. 



United States Department of A.i^mcnlture, 



DIVISION OF ENTOMOLOGY. 



THE DESTRIK TH E (illETrS PEA LOUSE. 



{Nectarojihoni (Icsiriictor Joliiis.) 



RECENT INJURY. 



One of the most destructive and troublesome insects of recent j^ears 

 is a little green plant-louse which, from its injuries to peas, is known as 

 the destructive green pea louse. Since it first attracted attention b}^ 

 its ravages in May of 1899 it has steadily increased in injuriousness, and 

 has been the cause of great loss in the principal pea-growing regions of 

 this country, especially where peas are grown for canning. It was, in 

 fact, one of the most important of all insects that ravaged crops in the 

 United States during the seasons of 1899 and 1900, and there appears 

 to be little prospect, unless the unforeseen happens, of any decrease in 

 its devastations. On the contrary, it is to be expected that it will widen 

 its range geographically, as it has apparently already done to some 

 extent. 



DESCRIPTIVE. 



This plant-louse is one of unusual size among those found infesting 

 gardens, and the largest of the green species which attack the pea and 

 related plants. The length of the body of winged, viviparous females 

 is about tV inch (4.5 mm.), and the total wing expanse about iV inch 

 (9 to 11 mm.). The general color of both the winged and apterous or 

 wingless forms is uniform pea-green, the same color as the insect's 

 favorite food plant. ^ 



1 The eyes are prominent and reddish brown in color. The antenn;e are lighter 

 than the body and the tubercles prominent ; the joints are darker than the rest 

 of the segments, the seventh joint filiform and fuscous. The legs are long and 

 conspicuous; tarsi, distal ends of tibitu, and femora fuscous. The nectaries are 

 fuscous at the tips, otherwise of the same color as the body. 



Note. — Several more or less comprehensive articles have been published^on this 

 insect, notably by Messrs. Johnson and Sanderson, of the Maryland and Delaware 

 Agricultural Experiment Stations respectively, as well as by the writer. The for- 

 mer gave it the scientific name which is used here, but the latter has recently 

 given reason to show that this insect is in reality a European form known as 

 NectaropJiora jnsi Kalt. The question of the identity of the species, as well as 

 other technical details, are necessarily excluded in the present circular, which 

 is prepared as an aid to the correspondence of this office and is drawn, in the 

 main, from matter already made public. — F. II. C. 



