6 



BULLETIN 807, U. S, DEPARTMENT OF AGRICULTURE. 



beans where the tissue was consumed by the larvse (PL I, figs. 4, a, 6, 

 and 5) . This " buggy " appearance lessens the salability of the beans. 

 Infested beans are not only reduced somewhat in weight (see Table 

 I) but their germinating power is also lessened, as will be shown 

 later on. 



Table I. — Showing amount of 'beans consumed hy the hroad-hean weevil. 



Number of weevils in beans. 



Weight of 

 50 beans. 



Weight 

 consumed. 



Percentage 

 consumed. 





Grams. 

 76, 970 

 74, 800 

 72,430 

 70,150 



Grams. 





1 



2,170 

 4,540 

 6,820 



2.81 



2 



6.89 



3 ... 



8.86 







This table shows that approximately 3 per cent of the weight of a 

 bean is consumed by the larva of each weevil developing in it. 



EXTENT OF DAMAGE. 



It is estimated that the area devoted to broad beans commercially 

 is at present about 3,000 acres for the dry beans, 100 acres for can- 

 ning green, and 1,000 acres for cover crops. In addition many hun- 

 dreds of acres are grown in small lots, back-yard gardens, etc., for 

 home consumption. The commercial production of dry beans for 

 market is at present about 50,000 bags, but has been, before weevil 

 damage became so general, as much as 200,000 bags. 



After a careful survey of the 1916, 1917, and 1918 crops of horse 

 beans, and of numerous samples taken by food inspectors of the 

 Bureau of Chemistry and the writer, Tables II and III were pre- 

 pared. 



Table II. — Summary of the percentage of infestation of the 1916, 1917, and 

 1918 crops of broad beans grown in California. 



Infestation. 



1916 crop. 



Number 

 of bags. 



Per cent 



of total 



crop. 



1917 crop. 



Number 

 of bags. 



Per cent 



of total 



crop. 



1918 crop. 



Number 

 of bags. 



Per cent 



of total 



crop. 



to 5 per cent 



5.1 to 10 per cent . 

 10.1 to 15 per cent 

 15.1 to 30 per cent 

 Above 30 per cent 



Total 



18, 851 

 8,366 

 6,835 



11,114 

 4,318 



38.10 

 16.88 

 13.81 

 22.46 



8.75 



15, 372 

 6,855 

 4,904 

 4,852 

 1,107 



46.46 

 20.71 

 14.82 

 14.66 

 3.35 



6,638 

 5, 341 

 4,629 

 10,547 

 3,681 



26.75 

 16.16 

 14.01 

 31.93 

 11.15 



49, 474 



100. 00 



33,090 100.00 



33, 036 



100.00 



