4S INJUKIO us INSECTS AND FUJSTGI. [Sept. 1894. 



It may be necessary to spray the plants again if heavy rains 

 should fall and wash off the dressing. 



If the disease still spreads after the treatment, it will be 

 desirable to repeat the spraying. 



Cost of Treatment. 



It has been stated that the cost of treatment usually varies 

 from 8s, 6d. to lis. per acre for each application of the 2 per 

 cent, of sulphate of copper composition. The composition with 

 the molasses costs from 10s. 6d. to 13s. per acre. 



The Bean Aphis (Aphis Rumicis). 



Among the many species of aphis that infest and spoil culti- 

 vated crops, the bean aphis was much in evidence during June 

 and July in bean-fields here and there throughout the country. 

 Some cultivators of beans said that the plants had splendid 

 haulm and blossoms, but complained that they were smothered 

 with insects. In certain districts this aphis is called the " black 

 dolphin." 



The quantities of aphides congregating upon the stems and 

 among the blossoms checked the formation of beans by con- 

 tinually exhausting the juices of the plants. 



The winged female aphis is black and somewhat shiny. The 

 larvae- — lice — are at first of a lighter colour, but they soon 

 become black. When the food supply on the beans ceases, 

 winged generations are evolved, which fly to weeds, such as 

 docks, thistles, borage, and to furze, broom, and other plants, upon 

 which continuity of existence is maintained during the winter. 



With respect to modes of prevention and remedies, it is 

 obvious that docks and thistles should be kept under as much as 

 possible. 



When it is noticed that beans are infested with aphides, the 

 tops should be cut off. They generally first appear near the 

 tops of the plants and gradually descend. It is a good practice 

 to cut off the tops of the beans during flowering, but when 

 these are infested they must not be left upon the ground, or 

 the aphides will crawl up the adjacent stems. 



In gardens and market-gardens infested beans may be advan- 

 tageously sprayed with a soft soap and quassia solution in the 

 proportion of 5 or 6 lbs. of soft soap, and the extract of 5 or 

 6 lbs. of quassia chips, to 100 gallons of water. It would be 

 difficult to spray on a large scale, but it is an effectual process. 



