PEANUT DISEASES 265 



(a) Type and quality of seed stocks: No amount of seed treatment 

 will change poor seed into good seed. Although not recommended, "pegs" 

 (shriveled, under-developed seeds) are still widely used as seed stocks. 

 The comparative effectiveness of seed treatment on plump and shriveled 

 seeds has been studied (46), and the results indicate that emergence 

 from plump seeds is always considerably higher than that from shriveled 

 seeds. When seeds are stored under conditions detrimental to quality, 

 any subsequent seed treatment will be less effective. Seed treatment, 

 therefore, is not a corrective for improper storage. 



(b) The use of unshelled seed. Usually there is no appreciable in- 

 crease in emergence as a result of treatment of unshelled seeds (103, 124, 

 155, 163). Pre-soaking Spanish peanut pods in water increases the sub- 

 sequent germination of unshelled seeds (67, 103, 124), but treatment of 

 pre-soaked pods gives no additional increase in germination (103). 

 Germination of pre-soaked unshelled Spanish peanut seeds usually is 

 less than that of treated- machine- or hand-shelled seeds (103). 



(c) Method of shelling. Injury by machine-shelling provides points 

 of entry for soil fungi, and emergence from untreated hand-shelled seeds 

 is much better than that from untreated machine-shelled seeds. Treating 

 hand-shelled seeds generally increases emergence, but the proportion 

 of increase is not as great as from treatment of machine-shelled seeds. 

 Emergences from treated machine-shelled seeds compare favorably with 

 emergences from untreated hand-shelled seeds (50, 105, 163). 



(d) Material used. The most apparent factor which can influence the 

 effectiveness of seed treatment is the chemical itself. Numerous fungicides 

 are designed exclusively for seed treatment. Three of these fungicides, 

 Arasan (50 percent tetramethyl thiuramdisulfide) , 2 percent Ceresan 

 (2 percent ethyl mercury chloride), and Spergon (98 percent tetrachloro- 

 parabenzoquinone) , have been tested so frequently that their effectiveness 

 is definitely established. The majority of reports show Arasan and 2 per- 

 cent Ceresan about equal, with Spergon less effective but still very benefi- 

 cial (45, 46, 50, 51, 53, 153, 155, 163, 167). Other newly introduced seed 

 fungicides have been tested and some give excellent promise. Extensive 

 testing should soon give definite evaluations for these newer seed fungi- 

 cides. 



(e) Methods. The method of applying seed fungicides influences 

 effectiveness of the treatment. A light film of the material on every seed 

 is desired. Higher rates of application do not give additional increases in 

 emergence (103), and over-dosage with mecurial treatments results in 

 abnormal germination and seedling death (67, 163). There are, un- 



