482 SOUTHERN FIELD CROPS 



in drills 2 feet apart.' This is probably the largest yield i 

 on record. A jaeld of 60 bushels or more of any variety 

 may be regarded as a good crop. The average of the 

 entire country in most j^ears is below 35 bushels per acre. 

 462. Enemies. — The peanut has few enemies either 

 among insects or among the minute organisms usually 

 concerned in the diseases of plants. 



The most common disease is a form of leaf-spot (Cercospora 

 personata). The symptoms are the appearance of brownish 

 spots on the leaves. This disease is more frequently noted on 

 sour or poorly drained land. If it appears late in the life of the 

 plant, it will often be practicable to mow the erect varieties for 

 hay before the disease has rendered the vines unfit for this use. 



In a few localities, especially around old premises, the peanut 

 plant is sometimes killed by a form of root rot {Fiisarium). The 

 symptoms are the presence of a mass of white threads on the stem 

 just below the surface, together with the appearance of minute 

 round, whitish, or brownish bodies, about the size of mustard 

 seeds,- clustered around the stem, close to the surface of the 

 ground. 



Doubtless rotation of crops, keeping off of the infected fields 

 most of the legumes and other susceptible crops, is the best means 

 of avoiding injury by this disease. 



LABORATORY EXERCISES 



1. Determine the weight of 100 shelled nuts of the Spanish 

 and of some larger variety. 



2. Determine the percentage of hulls in the unshelled dry 

 nuts of both the Spanish and some larger variety. 



3. If growing peanut plants are available, make a dra-ning 

 showing where the " pegs " or " needles " originate, and the 

 enlargement which they undergo after penetrating the soil. 



4. The principal laboratorj- work to accompany this chapter 



• Ark. Expr. Sta., Bui. No. 5S. 



