PECAN ROSETTE IN RELATION TO SOIL DEFICIENCIES. 7 
correctness of the view that pecan rosette is due to a deficiency of 
humus, plant-food material, and soil moisture. Consequent^, it will 
probably be three or four years more before definite and conclusive 
results can be had, but the improvement obtained during the first 
two years, together with the other evidence presented, makes a strik- 
ing case, and it appears reasonably certain that the improvement in 
the fertilized plats will continue until rosette is practically eliminated 
and nut production established in all of the fertilized trees. 
LIME AND ROSETTE. 
The use of lime as a remedy for pecan rosette has been strongly 
urged by some growers, and there appears to be a rather widespread 
belief in its efficacy for this purpose. Apparently this belief is based 
on the assumption that the disease is due to acid soil. That there is 
little or no reason for making such an assumption will be evident 
from a consideration of the facts in the case. 
The soils of the native habitat of the pecan — i. e., river flood 
plains — are practically all acid and yet rosette is a rarity on such 
soils. Practically all of the soils of the Atlantic and Gulf Coastal 
Plains are acid, yet as a whole the orchards planted on these soils 
show probably not more than 20 per cent of the trees rosetted. 
Tests for acidity by the litmus method have been made of soil from 
around 53 trees. The samples were taken to a depth of 4 feet and 
each foot tested separately. Of the 30 samples from rosetted trees, 29 
gave acid reactions and 1 was neutral. Of the 23 samples from 
healthy trees, 18 gave acid reactions and 5 were neutral. 
In the lime test, the results of which are given in Table I, the trees 
in the plat which received lime alone at the rate of 3 tons of ground 
limestone to the acre not only failed to improve, but were worse at 
the end of the third season following its application. 1 
There appears to be no reason to suppose that lime will be of any 
direct benefit in the treatment of pecan rosette. That it may be of 
indirect benefit in improving the physical condition of certain soils 
and in promoting the growth of legumes is highly probable, and 
when lime is used in rosetted pecan orchards this relation should be 
kept in mind. 
THE ROOT SYSTEM AND ROSETTE. , 
The fact that the pecan develops a long taproot probably explains 
the view so commonly held by growers that the tree draws largely 
on the subsoil for its plant-food material. The facts of the case are 
1 Similar results were obtained by Rand in experiments with lime. For details of these 
experiments, see Orton, W. A., and Rand, F. V., Pecan rosette,' in Jour. Agr. Research, 
vol. 3, no, 2, p. 149-174, 1916. 
