August, '191 



CAMPBELL: BEAN WEEVIL CONTROL 



285 



the suggestion that the same methods might be apphcable to the pea 

 weevil [Laria (Bruchus) pisorum], and possibly to the several bean 

 weevils. Dr. F. H. Chittenden is inclined to the belief that in some 

 localities, such as Washington, D. C, where two crops of peas can be 

 grown each year, late planting will result in sound seed stock, but 

 according to available information, this is the first time the matter has 

 been definitely followed for several seasons, and by a large number of 

 observations and experiments the theory of late planting definitely 

 proved. 



The broad bean weevil is found in California wherever broad or 

 horse beans are grown, but the principal districts are around San Fran- 

 cisco Ba,y, and down the coast to a little below San Luis Obispo. 

 Alameda County formerly was the most extensive producing section, 

 but due largely to heavy weevil infestation of practically all beans 

 grown there, it is now of no commercial importance as a horse bean 

 section. The following table, showing the infestation of broad beans 

 from the Oceano-Morro and Sacramento districts, from numerous 

 samples taken and tested by pure food inspectors of the Bureau of 

 Chemistry,^ and by the writer, is typical of all other districts. 



Table L Summary of the 191G, 1917 and 1918 Crop of Broad Beans from the Oceano-Morro 



AND Sacramento Districts 



Sacramento is the newest horse bean section, and a glance at the 

 table will show that not only the maximum per cent of weevil infesta- 

 tion of beans produced there, but also the average, increased each 

 year. The low percentage for the Oceano-Morro sections for 1918 

 will be explained later. 



Life History 



The eggs are laid on the surface of the green bean pods in the field. 

 No eggs were observed by the writer except on the pods, the latter 

 varying in size from less than an inch to over five inches. Most of the 

 eggs are laid on the larger pods. 



' The writer i.s inclehted to the Western Divi.'^ioii of the Bureau of Chemistry, and 

 Mr. M. A. Rex, pure food inspector, for .supplying all the data they had collected on 

 the horse bean crop of California for the last four years. 



