[FLETCHER] 



INJURIOUS INSECTS OF CANADA 



211 



is known of the habits of the species. Experiments are now being 

 carried on "with the view of discovering practical means of avoiding 

 loss. 



Bean Aphis— natural size and enlarged. 



EooT Ceops and Vegetables. 



The Bean Aphis or Black Dolphin {Aphis rumicis, L.). — The 

 Broad or Windsor Beans and Horse Beans are not grown to any ex- 

 tent in Canada. A few years 

 ago (1892), however, an eftbrt 

 was made to introduce Horse 

 Beans into cultivation for use 

 as a highly nitrogenous fodder 

 plant. It was not long (1894) 

 before the well-known pest of 

 the Broad and Horse Beans, 

 the " Black Dolphin " of Eng- 

 lish farmers, made its appear- 

 ance, and was one of the 

 causes which prevented these 

 useful plants fi'oni being much 

 more widely grown in this country. At the same time (1894) the bean 

 plants were severely attacked by a native leafdiopper, the Bean Thrip 

 (Empoafabœ, Harr.), which occasionally does slight injury to the field 

 beans ordinarily cultivated. 



The Bean Weevil (BriicJnis obtectus, Say). — The latest addition to 

 the insect enemies of the Canadian farmer is the Bean Weevil (Eep. 

 Exp. Farms, 1898), which not only destroys the seeds while in the pod 

 in the fields, but also propagates among the dry grain when stored. It 

 is hardly likely that this will ever become' a regularly occurring pest, 

 but like the grain and rice weevils {Calandra), it will appear at intervals 

 and then be lost sight of. The best remedy for this insect, as with the 

 well known Pea Weevil {BrucJius pisorum, L.), which in many points 

 has a similaii life history, is the destruction of the weevils inside the 

 seeds as soon as possible after the crop is harvested. Fumigation with 

 bisulphide of carbon is the best treatment in every way. It must not 

 be forgotten that this liquid and its vapour are very dangerous to use, 

 owing to their extreme inflammability. The most convenient way to 

 fumigate seed is to place it in an ordinary coal oil barrel and pour on 

 the beans one ounce of the bisulphide of carbon for every 100 pounds 

 of grain, then close the barrel tightly, first with a wet canvas or cloth, 

 and, on the top of this, witli boards which should be left undisturbed 

 for two days at least. 



