The Bulletin. 13 



Rotation for Frames.— 



1. Lettuce September to December. 



2. Beets January to April. 



3. Cucumbers April to .Tuly. 



4. Cowpeas July to September. 



1. Lettuce December to March. 



2. Cucumbers March to July. 



3. Cowpeas July to October. 



1. Lettuce September to December. 



2. Radish Februai'y to March. 



3. Beans .March to June. 



4. Cowpeas June to September. 



1. Lettuce December to March. 



2. Eggplant March to June. 



3. Cowi>eas July to November. 



Rotation for Field.— 



1. Lettuce December to March. 



2. Potatoes March to June. 



3. Corn Jmie to October. 



4. Cowpeas Sowed at "laying-by" of corn. 



1. Lettuce December to March. 



2. Cantaloupes March to July. 



3. Cowpeas July to October. 



1. Lettuce December to March. 



2. Tomatoes March to July. 



3. Cowpeas July to October. 



It will be noticed that cowpeas find a place in each of these rota- 

 tions. The cowpea crop is the cheap method of supplying vegetable 

 matter and nitrogen for successive lettuce crops. 



With a proper rotation, including cover crops and care in avoiding 

 disease, it is possible to grow lettuce on the same land year after year. 



DISEASES. 



Owing to dryness of the air, sunlight and better ventilation, win- 

 ter lettuce in North Carolina is not affected by the many diseases to 

 which the crop is usually subject where grown under greenhouse cul- 

 ture. There is, however, one disease which, even under these condi- 

 tions, proves quite destructive. This is commonly known as lettuce 

 "drop," "damp," or "wilt." This disease is caused by the action of 

 a minute parasitic fungous plant that grows and thrives in the tissue 

 of the lettuce plant. The disease spreads by means of small, dark 

 bodies known as sclerotia, varying from the size of a flaxseed to that 

 of a wheat grain. These lie in the soil and carry the disease over 

 from crop to crop. The plant becomes infected when small, and the 

 disease grows, hidden in its tissues, till about the time of heading, 

 when the whole plant drops down in a single night. On examination 



