146 INSECTS AFFECTING VEGETATION 



them one ounce of bisulphide of carbon for every 100 pounds, and 

 then closing the receptacle tightly and leaving it for 48 hours. At 

 the end of this time every insect will be dead. As the fumes of this 

 substance are inflammable and explosive, it should not be used near 

 any light or fire. Beans that have been injured by the insect should 

 on no account be used as seed, as most of them will fail to germinate, 

 or at any rate will produce only feeble plants. 



The Bean Plant-Louse. Windsor or Broad Beans and Horse- 

 beans are not much grown in this country, though in some places 

 they are found of value as an addition to ensilage. Some difik-ulty 

 is experienced in obtaining satisfactory crops owing to their liability 

 to attack by this black Aphis, which is a serious pest in Europe. At 

 the time of flowering the colonies of this insect are to be found cover- 

 ing the tips of the plants so thickly that they look as if dusted with 

 soot ; if let alone they soon multiply enormously and greatly reduce 

 the vitality of the plants. 



The most successful plan is to cut off the tips of the affected 

 plants and destroy the colonies of Aphis by burning or trampling 

 under foot. This has the additional benefit of checking the growth 

 and causing the pods to fully develop. Spraying with kerosene 

 emulsion or strong soap-suds will also be effective. 



Other Insects. Beans, like other vegetables, are liable to be in- 

 jured by Cutworms when the plants are small, and later on in the 

 season by the Tarnished Plant-bug. Broad beans are also subject to 

 attack by the Black Blister-beetle, which is one of the enemies of the 

 potato plant, and sometimes appears in destructive numbers. 



The Bean Leaf-Roller. The bean leaf-roller is quite destruc- 

 tive to -beans. The larvae feed upon the leaves, eating holes in 

 them or eating along the edges. Leaflets are folded over, to form a 

 retreat. 



The larva is about one and one-fifth inches in length, fusiform 

 in shape, the body being thickest in the middle, with small neck 

 and large head. The general color is yellowish, with a dorsal black 

 strip, and two lateral orange stripes extending down the body. 



The insect can be successfully treated. Use Paris green, in the 

 proportion of one pound to 150 gallons of water, add to this one 

 pound of quicklime, first made into a thin paste, to destroy the 

 burning effects of Paris green on the foliage, or arsenate of lead 2 

 Ibs. to 50 gallons of water. Apply with spray pump, keeping mix- 

 ture well stirred. (Bui. 45 Fla. Agr. Exp. Sta.) 



BEETS AND SPINACH. 



Blister Beetles. Beets and spinach are liable to be attacked by 

 many of the common garden pests that are general feeders, such as 

 Cutworms which bite off the young plants close to the surface of the 

 ground, Wire-worms and White-grubs which feed upon the roots, 

 Flea-beetles, Leaf-hoppers, the Tarnished Plant-bug and Grasshop- 

 pers which affect the foliage. Descriptions of these insects and the 

 methods of dealing with them will be found elsewhere. Mention 

 may be made of a few other insects which occasionally attack these 

 plants in injurious numbers. 



