UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1378 
Washington, D. C. ▼ February, 1926 
RELATION OF SOIL CONDITIONS AND ORCHARD MANAGEMENT TO THE 
ROSETTE OF PECAN TREES 
By J. J. Skinner, Biochemist, Office of Soil- Fertility Investigations, and J. B. 
Demaree, Assistant Pathologist, Office of Fruit-Disease Investigations, Bureau 
of Plant Industry 
CONTENTS 
Effect of soil treatment on the rosette of pecan trees 2 
Norfolk fine sandy loam 2 
Greenville sandy loam 7 
Laboratory examination of soils from rosetted and from nonrosetted pecan orchards 10 
Orchard soils examined - 10 
Discussion 13 
Examination of the soil of good and of poor sections of orchards free from rosette 13 
Summary 16 
The rosette of pecan trees is generally attributed by investigators 
and growers to unfavorable soil conditions. Whether rosette is a 
result of an unbalanced condition of nutrients in the soil, a lack of 
available soil moisture, a deficiency of organic matter, or is due to 
several of these factors has never been definitely determined. How- 
ever, it is generally accepted that a lack of moisture and a deficiency 
of soil nutrients play an important part * in the development of this 
disease. 
The relation of soil conditions to pecan rosette has received much 
attention from growers and investigators. McMurran 2 showed that 
the evidence of rosette in badly affected pecan trees was greatly 
reduced by heavy applications of stable manure. Whether the 
improved condition in the appearance of the trees is due to the 
additional plant food in the soil or to the greater ability of the soil 
to retain moisture during droughty periods as a result of the added 
organic matter is not definitely known. Further investigations by 
the United States Department of Agriculture, which should throw 
some li^ht on these point?, are in progress. 
1 Orton, W. A., and Rand, F. V. Pecan rosette. In Jour. Agr. Research, v. 3, p. 149-174. illus. 1914. 
Rand, F. V. Pecan rosette: Its histology, cytology, and relation to other chlorotic diseases. I". 9. 
Dept. Agr. Bui. 1038, 42 p., illus 1922. 
1 McMurran, S. M. Pecan rosette in relation to soil deficiencies. U. S. Uept. Agr. Bui. 756. 11 p., illus. 
1919. 
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