286 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



The eggs hatch in from 9 to 18 days, the young larvse boring directly 

 into the pod, and from thence into the nearest bean, in which they 

 feed during the remainder of the larval life. The duration of the latter 

 is from 10 to 15 weeks. Pupation takes place within the bean, in the 

 cell eaten out by the larva, and requires from 7 to 16 days. 



The adult may emerge from the bean immediately, or remain within 

 it for several months. The length of the adult life is from 1 to 8 

 months. 



Seasonal History 



While the first eggs are laid soon after the middle of March, and a 

 few may be laid as late as the middle of May, the most extensive 

 deposition occurs during the month of April. Larvse may be found 

 from the latter part of March to the middle of October; pupse from 

 the first of August to the latter part of October, and adults from the 

 middle of August to the following June. 



Although a few adults live until June, by far the greater number die 

 off several months sooner. In storage 90 per cent of the weevils are 

 dead by the first of April. Field observations at Hayward showed 

 that the first active weevils were observed in broad bean fields on 

 March 25, that the number increased until May 4, after which it 

 decreased constantly until June 15, the last date any live adults were 

 observed in the field. 



Cultural Methods of Control 

 Time of Planting 



The planting season for horse beans begins soon after the first fall 

 rains, usually in October or November, and contiriues until late spring. 

 Horse bean buyers and growers have noticed for some time that beans 

 from seed planted early in the season usually have a higher percentage 

 of weevil infestation than beans from seed planted later. This was 

 checked up by making a table from the data collected by the Bureau 

 of Chemistry, whose inspectors, when taking samples of horse beans, 

 ascertained as far as possible when the seed had been planted. About 

 20,000 sacks from seed lilanted early, that is before January 1, in 1916 

 and 1917, gave an average of slightly over 33 per cent of the beans 

 infested, while about 7,500 sacks from seed planted late, or after March 

 1, averaged 6.4 per cent weevil infested. 



From numerous samples taken of crops planted in certain months 

 in the three seasons, 1916 to 1918 inclusive, the following averages 

 were obtained: 



