May x6,1921 
Bacterial Wilt of Castor Bean 
257 
On one field of 295 acres at Ocala, Fla., this contrast was particularly 
striking. No wilt whatever was observed in the main part of the field, 
which had been under cultivation for many years. On a new section 
of the field, which had been cultivated only two years and which 
adjoined pine woods, wilt occurred in varying amounts, running from 
one-tenth of 1 per cent to 10 per cent in different spots. It was typical 
rolling pineland with little humus. The older land was originally the 
same but had developed considerably more humus and a darker color. 
A field at Frostproof, Fla., was inspected on June 6. This field was 
made up entirely of new land cleared and plowed in January and Feb¬ 
ruary, 1918, and planted in March. The wilt occurred in certain areas, 
especially in the lower portions of the field, to the extent of 5 to 10 per 
cent. Several other fields in the same general locality, which had been 
under cultivation for several years, showed a complete absence of 
the wilt. 
At Mulberry, Fla., a plot of 80 acres of low pineland, with saw palmetto 
in the lower spots, was cleared in the latter part of February and planted 
March 13. While this gave an excellent stand of castor beans, wilt 
occurred throughout to the extent of one-tenth of 1 per cent to 5 per cent. 
A few square rods planted early in May (very late) showed numerous 
wilted plants. 
The junior writer likewise inspected a field in Dothan, Ala., in which 
the only wilt to be found, was in a newly cultivated end of the field 
adjoining pine woods. 
The senior author has frequently observed this disease in tomatoes 
grown on “new land” in Florida. 
Due to the fact that there were no extensive commercial plantings in 
1919, the only observations on the disease in 1919 were in some experi¬ 
mental plantings made by the junior author at Orlando, Fla. As early 
as April the first cases of wilt were to be found, and from that time on till 
at least June 16 new cases were appearing almost daily. These cases all 
occurred on sandy land which had not been under cultivation for some 
years. 
SIGNS OF THE DISEASE IN THE FIELD 
The signs of the bacterial wilt on Ricinus are, in general, the same as 
on other plants described in detail by Dr. Erwin F. Smith, in “Bacteria 
in Relation to Plant Diseases,” 1 and in earlier publications. The disease 
in this plant, as in the Solanaceous plants, is a true wilt of the green 
leaves and growing points, without previous yellowing or other partial or 
complete discoloration (PI. 55). It may occur when the plants are small, 
only 2 or 3 inches high, in which case it is likely to prove fatal. It is also 
found in plants of all sizes up to several feet high. In smaller plants a 
single leaf may wilt, and the vascular system near the base of the plant 
1 Smith, Erwin E. bacteria in ruination to pi*ant diseases, v. 3. Washington, D. C. 1914. 
