206 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 12 



NOTES ON SOME LITTLE KNOWN PESTS OF RED-CLOVER 



By Glenn W. Herrick and J. D. Detwiler 



During the past few years, a more or less continuous study of the 

 insect pests of red clover has been carried on at Ithaca. Interruptions 

 have occurred from time to time but a special effort was made last 

 season by the writers to continue the investigation. It seemed that 

 a study of clover insects in New York was of special significance in 

 time of war. Clover is the principal crop in the northern states for 

 the maintenance of the fertility of the soil and upon it, in great meas- 

 ure, depends the production of farm crops in a continuously average 

 amount. Therefore any measure that will conserve clover and espe- 

 cially clover seed is of direct aid in a food crisis of this country. With 

 this thought in mind the writers made special effort during the past 

 summer to investigate the life-histories and injuries of three little 

 known pests of red clover that occur abundantly in the vicinity of 

 Ithaca. These are the lesser clover-leaf weevil, Phytonoyyius nigriros- 

 tris, the clover-head weevil, Phytonomus nieles, and the clover tychius, 

 Tychius picirostris. 



The infestation of the first two species could hardly be considered 

 severe as counts of infested and uninfested heads show. On June 29 

 a count was made of a total of 400 heads. Of these 6 per cent of the 

 ripened heads, 1.8 per cent of those in bloom, while 7+ per cent of the 

 immature heads were found infested. On July 1 another lot of heads, 

 a total of 340, gathered near the border of a clover plot were examined 

 for the presence of the weevil. Of these 21 per cent of the mature 

 heads, 4 per cent of those in bloom, and 2.2 per cent of the green ones 

 were found infested. In this case the percentage of infestation in the 

 mature heads was highest. Again on July 2 a count of 403 heads was 

 made. Of these 7 per cent of the ripened heads, 3 per cent of those in 

 bloom, and 2 per cent of the green heads were infested. Here also the 

 highest infestation was among the matured heads. 



The Lesser Clover-Leaf Weevil, 

 Phytonomus nigrirostris Fab. 



This weevil (Fig. 8) was found in 

 considerable abundance in clover 

 fields at Ithaca. The larvae were 

 at work in immature heads, in those 

 in bloom, and in those that had 

 ripened. During the last days of 

 June when this investigation began, 

 larvae and pupse, and empty co- 



Fig. 8. 

 Thorax. 



Phytonomus nigrirostris; a. 



