167 



The cost of sack-banding and collection is reckoned at less than 

 one penny per tree. 



The effect of various grease-bands, as an alternative to sack-banding, 

 has been tried ; of these only tanglefoot had any ei?ect on the larvae 

 and this can be considered a poor deterrent. 



Parasites of H. robusta, about which it is hoped to obtain some 

 information, are not very extensive, but include several Chalcidids, 

 Ichneumonids and Braconids. 



Campbell (R. E.). The Broad-bean Weevil. — U.S. Dept. Agric., 

 Washington, B.C., Bull. 807, 27th January 1920, 22 pp., 1 plate, 

 6 figs. 



The growing of broad or horse beans in Cahfornia has been seriously 

 handicapped during the last few years owing to infestation by Bruchus 

 rufimanus, Boh. The practical impossibihty of growing iminfested 

 beans has caused many acres to be abandoned, especially since under 

 the Federal Food and Drugs Act infested beans are classed as adulter- 

 ated food. It is now permissible to export beans containing not more 

 than 15 per cent, of infestation. Besides being used as food for 

 stock the horse bean is used as a green vegetable and also to 

 a considerable extent as a winter cover crop. The stages of 

 B. rufimanus are described and are compared with those of B. pisorum. 

 There is only one generation of B. rufimanus in a year and the beetle 

 does not breed in dry beans ; seed held over until a second year is there- 

 fore free from infestation. The eggs are laid on the green bean pods in 

 the field from the middle of March to mid-May, the incubation period 

 lasting from 9 to 18 days. The young larva eats its way into the bean 

 pod and continues feeding until it is mature, when it eats a round 

 hole in the cotyledon directly under the epidermis, leaving a half- 

 transparent skin which is easily broken by the adult weevil when 

 ready to emerge. Death frequently occurs among the larvae after 

 entering the beans. From 5 to 16 larvae may enter a single bean, 

 but seldom more than two adults emerge. The larva is mature 

 after 10 to 15 weeks and pupates within the bean, the pupal stage 

 lasting from 7 to 16 days. The adult may emerge at once through 

 the broken skin or it may remain in the bean for several months, 

 and many individuals never emerge at all. The beetles frequently 

 emerge after the beans have been planted, the adult hfe lasting from 

 1 to 8 months. 



Germination of infested beans is foimd to be from 20 to 40 per 

 cent, less than that of uninfested ones, though the germination of 

 seed a year or more old is only sHghtly less than that of new seed. 



There are no natural enemies of any importance affecting B. rufi- 

 manus in America. The predaceous mite, Pediculoides ventricosus, 

 Newp., has been observed attacking a few of the beetles. 



Experiments in remedial measures showed that a temperature of 

 170° to 180° F. for half an hour is necessary to kill all the beetles 

 in beans. Sulphur proved to be unsatisfactory as a fiunigant. 

 Fumigation with carbon bisulphide at the rate of 7 lb. per 1,000 cub. 

 ft. in an air-tight box for 24 hours Idlls all the beetles. Late planting 

 is advisable ; beans from crops planted after 1st March are much 

 less infested than those planted from November to March. 



