Culture and Utilization of the Field Pea 747 



INSECT enemies 



Pea Weevil 



The pea weevil (Laria pisorum Linn.), the most serious enemy 

 of the field pea/ is a small grayish or brownish-gray beetle, marked 

 with lighter spots. The insect lays its eggs on the young pod. This 

 egg hatches and produces a larva, which bores through the wall 

 of the pod and enters the young pea, where it feeds on 

 the growing embryo and later pupates. The pupa remains in 

 the seied until the next seaison, usually emerging from the pea the 

 following spring. However, the behavior of the weevils is unfor- 

 tunately not uniform in this respect, as many of them emerge 

 sooner, and the dates of emergence will range from harvest to 

 planting time the following year. One remedy for the attacks of 

 the weievil is to store in tight bags the seed intended for planting 

 and hold it over for one year, in which case the beetle will emerge 

 from the seed and die before the next planting season arrives. 



Another method em])loyed by seedsmen is to fumigate the seed 

 with carbon bisulphide, which can be obtained at a reasonable cost 

 from any druggist. In applying this remedy the seed must be 

 placed in a tight box or barrel and expoised from 30 to 48 hours 

 to the fumes of this liquid. The carbon bisulphide should be 

 exposed in a shallow dish placed on top of the peas, since the vapor 

 is heavier than air. When mixed with air, this vapor is quite 

 inflammable. Hence, care should be taken not to ignite it in any 

 way, or a serious explosion may occur. One pound of the liquid is 

 usually considered sufficient to fumigate 100 bushels of peas, but it 

 is well to use somewhat more than this in order to be sure of killing 

 all the insects. 



Continuous cropping of the land to the field pea is almost sure 

 to mean a constant increase in the numbers of the pea weevil. 

 Practically the only remedy for this state of afi^airs is to stop 

 growing peas for several years, in which case the weevil will be 

 exterminated through lack of food. 



1 Chittenden, F. H., Insects Injwious to Bea/ns wtid Peas. U. S. Dept. Agr. 

 Year Book for 1898, pp. 233-260, figs. 66-82, 1899. 



