294 THE FORAGE AND FIBER CROPS IN AMERICA 



disinfect seed by soaking for 15 minutes in a 0.001 corrosive sublimate solu- 

 tion, or in formalin, one pound to 30 gallons, and dry before sowing. The 

 disease not being thoroughly understood, no satisfactory method of controlling 

 the disease in the field has been found. 1 



The larva of the wavy striped flea beetle (Phyllotreta vittata Fab.) fre- 

 quently attacks the roots of the plants, destroying many of them. The most 

 practical preventive is early seeding. Sowing thickly and thinning, if necessary, 

 may bring good results. 



The green cabbage worm (Pontia rapae Sch.) is a serious pest. It is 

 important to kill the first spring brood, which becomes mature in two or three 

 weeks. If practicable, hand picking early in the morning for the first two 

 or three weeks of the seedling will prove beneficial. Spraying the young 

 plants with an arsenious solution and the old plants with pyrethrum or hel- 

 lebore is reccmmended for this pest, and for the cabbage looper (Autographa 

 brassicae Riley). The harlequin cabbage bug (Murgantia histrionica Hahn.) 

 is a serious pest in the southern states. Once it gets a hold it is liable to 

 remain. While mustard and radish plants are recommended to be sown for 

 traps, when the bugs may be destroyed by spraying with kerosene, this practise 

 more frequently increases the numbers and the only effective means of com- 

 bating so far found is hand picking. The cabbage maggot (Pegomya brassicae 

 Bouche), and the cabbage plant louse (Aphis brassicae L.) sometimes do con-' 

 siderable injury. Spraying with whale oil soap solution has been found an 

 effective remedy for the latter. 



371. Yields. The yield of dry matter or fresh substance is 

 not so large in rutabagas as in mangels, and in common turnips 

 it is even less. (359) Five to fifteen tons of common tur- 

 nips and 15 to 20 tons of rutabagas and kohlrabi may be con- 

 sidered fair yields. Under favorable conditions over 40 tons of 

 cabbage of stock feeding purposes may be obtained, 20 to 30 tons 

 being frequent. Cabbages usually contain 6 to 7, common tur- 

 nips 7 to 9, rutabagas 8 to 10, and kohlrabi 9 to n per cent, of 

 dry matter. 



372. Value. The common turnip is valued as a catch crop, 

 and may be used for feeding on the ground early in the sea- 

 son. For the farmer who wishes to raise "roots" to supplement 

 the grain ration in Canada and the cooler and moister portions 

 of the United States, where maize is a rather uncertain crop, 

 cabbage may be grown for feeding cattle and sheep while on 



iNew York State Sta. Bui. No. 232 (1903); 251 (1904). 



