INSECTS INJURIOUS TO CABBAGE, ETC. 



339 



foliage a good thick coating, for the spray probably acts fully 

 as much as a repellant as a remedy. Where injury is antici- 

 pated it will be well to dip the plants in arsenate of lead 1 pound 

 to 10 gallons of water when planting them. By thoroughly dust- 

 ing the plants with lime, land plaster, strong tobacco dust, dilute 

 pyrethrum, or any of the dusts commonly used for such insects, 



FIG. 285. The striped turnip flea- FIG. 286. The western cabbage flea- 

 beetle (Phyllotreta vittata Fab.): beetle much enlarged. (After Riley, 

 a, larva; b, adult greatly en- U. S. Dept. Agr.) 

 larged. (After Riley, U. S. 

 Dept. Agr.) 



applying the dust in the early morning while the dew is on the 

 plants, they may be protected from attack as long as they are 

 kept thoroughly covered. It is evident that the weeds upon 

 which these pests develop in the larval stage should be destroyed. 

 Where plants are attacked in the seed-bed, screening as advised 

 for the root-maggot will prevent injury. Cloth with from 20 to 30 

 threads to the inch has proven most satisfactory for the screens, 

 which should be applied early and be made perfectly tight. 



