282 THE PEANUT— THE UNPREDICTABLE LEGUME 



D. Harvest peanuts as soon as practicable from fields in which 

 Sclerotium blight is bad. 



E. Abandon from peanut culture for several years fields in which 

 Sclerotium blight appears exceptionally severe. 



F. Follow a strict rotation policy in which grass crops play a promi- 

 nent role in all peanut fields. 



DISEASES OF MATURATION— SOIL ROTS OF FRUITS 

 (PEGS AND PODS) ' 



In the following discussion the gynophore or fruit stalk is called the 

 "peg" and considered a part of the peanut fruit. The shell and seed por- 

 tion of the fruit is called the "nut" or "pod." The peanut fruit is usually 

 called a "peanut" or a "nut." The peanut differs from most legumes in 

 that the fruit matures underground and in that the gynophore is con- 

 siderably elongated. This elongated fruit stalk is usually called the "peg," 

 although shriveled, under-developed peanut seeds are also called "pegs" 

 in some sections. 



Importance. By harvesting time in the southeastern United States 

 many nuts are partially or completely rotted and many seeds of Spanish 

 peanuts have sprouted in the pod. Many nuts pull off the vines and are 

 left in the soil. These losses result either from rots or from the pegs be- 

 coming mature, brittle or otherwise weakened before harvest. These path- 

 ological and physiological factors are undesirable aspects of the matura- 

 tion process and are "maturation diseases." 



Several surveys have noted these maturation diseases as important in 

 peanut culture (11, 95, 96, 119, 125, 127) and a few figures or estimates 

 of importance are available. In \'irginia and North Carolina in 1931 

 (95) up to 10 percent of the marketed nuts were rotted or "pickouts." 

 The same year losses due to soil rots were estimated as : Virginia 5 to 10 

 percent ; North Carolina 5 percent average ; South Carolina 5 percent aver- 

 age on most soils ; Georgia 10 to 30 percent in most localities and up to 

 50 -percent in others ; Alabama from 1 to 30 percent in various localities 

 (98). Surveys in 1943 estimated losses from maturation diseases as: 

 Virginia 30 percent in one section and from 5 to 50 percent in all sections 

 (150) ; North Carolina a loss of $20 to $50 per acre; Alabama an esti- 

 mated average of 12 to 15 percent (139). 



Description. Following pollination the peduncle (gynophore) of the 

 pistil elongates rapidly and becomes the peg. This forces the ovulary into 

 the soil where most development takes place. Usually at maturity all of 

 the nut and most or all of the peg are in the soil. The peanut fruit ma- 

 tures, then, under conditions conducive to attacks of microorganisms. 



