1756 



SWEET POTATO 



SWEET POTATO 



are stored in large bulk, without sufficient 

 opportunity to dry out. It is perhaps the 

 main cause of loss with stored potatoes, 

 developing rapidly and immediately, under 

 favoring conditions, and reducing, some- 

 times in a few weeks, the entire contents 

 of a bin or hill to a pulpy mass of cor- 

 ruption, emitting a most disgusting odor. 

 A few simple remedial measures will 

 greatly reduce loss from this cause: (1) 

 Dig only when soil is dry. (2) Dig be- 

 fore tubers become sappy from a " second 

 growth." (3) Remove all affected tubers 

 before storing. (4) Use padded baskets 

 in handling to avoid abrasion. (5) Store 

 in small bulk and keep dry and well ven- 

 tilated. 



(b) Black Rot (Ceratocystis fimbriata) : 

 The fungus producing this affection does 

 not depend so much on the conditions of 

 moisture and abrasion, and is slower in 

 making its appearance than is the soft 

 rot, continuing to develop, however, all 

 through the winter and often completing 

 the destruction the other has begun. It 

 is all the more to be dreaded because it is 

 not so immediately noticeable, and tubers 

 containing its germs are more likely to 

 be housed. The black rot does not pro- 

 duce a pulpy mass, though effectually de- 

 stroying the entire tuber. It frequently 

 makes its appearance on the young draws 

 at "setting-out time." Remedy: careful 

 selection 1st, of sound tubers for bed- 

 ding; 2d, of perfectly healthy draws for 

 setting; 3d, where these conditions can- 

 not be fully complied with, by planting the 

 bulk of the crop with cuttings from the 

 vines, thus minimizing the damage. The 

 use of copper sulfate, or any of the stand- 

 ard fungicides, either as a spray or for 

 soaking the tubers, is not advisable; for, 

 since the mycelium of most of the fungi 

 causing decay in the Sweet Potato is 

 lodged in and protected by the interior 

 cells of the tuber, surface treatment would 

 prove more or less futile. 



(c) Soil Rot (Acrocystis Batatas): This 

 fungus, as its name implies, is a resident 

 of the soil rather than of the tuber, and 

 hence cannot be readily guarded against. 

 It is responsible for most of the decay 

 observed in the crevices or cracks of split 

 tubers. Sudden expansion of vegetable 

 tissue due to a resumption of rapid growth 

 when wet weather follows a period of 

 drought, particularly when the soil is a 

 stiff clay, produces the primary "crack- 

 ing " and the spores of the fungus, finding 

 a ready lodgment, start the process of de- 

 cay. As for remedies, heavy applications 

 of sulfur to the soil have been found to 

 check its ravages in a measure, but this 

 method of operation is not practical. That 

 is to say, while checking the fungus the 

 result is not commensurate with the cost. 

 The surest preventive and this is true 

 for any and all rots is rotation. The 

 same areas should never be planted in 

 potatoes two years in succession, nor 

 should the same spot be used twice for a 

 hotbed to furnish draws, even at the cost 

 of great inconvenience in establishing the 

 bed in another place. 



(d) Other fungi: Several other fungi are 

 serious enemies of the Sweet Potato, as the 

 stem rot, white rot, dry rot, potato scurf, 

 leaf blight, etc.; but their ravages will 

 not compare with the damage produced 

 by the first three soft rot, black rot and 

 soil rot. 



As for the first three, it matters little 

 to the practical grower whether or not he 



2446. Leaves of Sweet Potato, 



Adapted from Bulletin of the 

 Georgia Experiment Station. 



is abie to distinguish one from another* 

 After the conditions favoring the spread 

 of one of them have been permitted to- 

 develop and the resulting decay once ap- 

 pears, it is usually too late to put reme- 

 dial measures into effect. Remedy, in this 

 case, must piecede manifestation of dis- 

 ease. Every possible precaution should 

 be observed at one and the same time 

 against them all. Proper preventive effort 

 during harvesting will be found a surer 

 guarantee against loss from decay than 

 the most elaborate structure or the most 

 carefully detailed method of housing yet 

 devised, and when thoroughly enforced 

 little apprehension need be felt as to re- 

 sults, no matter what plan of preserva- 

 tion is adopted. 



To this end the following summary of 

 procedure will be found serviceable : 



a. Rotate the crop. Never plant twice 

 in succession on the same land. 



b. Rotate the bed. Never use old soil 

 or old manure a second season. 



c. Dig only when the soil is dry. 



d. Dig before tubers are rendered moist 

 and sappy by a "second growth," and to- 

 this end never plant too early in spring. 



e. Use padded baskets in handling to- 

 prevent bruising and abrasion. 



f. Handle with scrupulous care. 



g. Reject all affected tubers before stor- 

 ing. 



h. Store dry, in small bulk; if in bins 

 erect bulkheads and use flues for ventila- 

 tion. 



i. Use only perfect tubers for bedding,, 

 rejecting any showing symptoms of decay. 



j. Use only healthy and unaffected 

 draws for setting out. 



k. When draws in bed are affected with 

 diseased roots (black rot) and cannot be 

 thrown away, plant in a separate plat and 

 take cuttings from their vines later for 

 the main crop. 



Varieties. Sine e new varieties of 

 the Sweet Potato can originate only by 

 bud variation, it is a marvel where and 

 how all of the different types arise. The 

 writer has personally cultivated and 

 tested some fifty odd kinds, and there- 

 doubtless exist, in all, 75 or 80 the num- 

 ber still increasing. But one uniform 

 method of classification exists that by 

 the "leaf" into tribes, falling under the* 

 three heads, "Leaves entire," "Leaves 

 shouldered or lobed " and "Leaves cleft"' 

 commonly termed "round - leafed," 

 "shouldered" and "split-leafed," respec- 

 tively. Of these the second type is the 

 most numerous, containing probably two- 

 thirds of the entire list. 



As for the best variety, 'the "all-round" 

 potato has not yet been found, nor is it 

 likely to be, since such a type should be 

 a tremendous yielder, of first quality, a 

 safe keeper and free from disease. No 

 potato -embodies, superlatively, all of 

 these characteristics. All of the heaviest 

 yielders belong, unfortunately, to the 

 "milky" or "turpentine" group as Nor- 

 ton, Hayman, Southern Queen, White St. 

 Domingo, Early Golden, etc., and their 

 sappy consistency prevents them from 

 keeping well, while their quality is uni- 

 formly poor. Regarding quality, however, 

 tastes differ. The northern market prefers 

 a dry, mealy potato, represented by the 

 Jersey or Nansemond strain. The southern 

 market, on the other hand, demands a 

 rich, sugary potato, like the Georgia or 

 Yellow Yam, which is generally considered 



