152 Journal of Agricultural Research voi.111.N0.2i 



PRUNING EXPERIMENTS 



If the rosette were of a parasitic nature, it seemed entirely possible 

 that a severe pruning out of the diseased parts or at least a cutting back 

 to the stump might entirely eliminate the disease. To test out this propo- 

 sition, 10 distinctly resetted trees in the orchard of Mr. J. B. Wight, 

 Cairo, Ga., were severely pruned and 5 similarly diseased trees were cut 

 off at the ground and allowed to send up sprouts from the stump. This 

 work was done in the winter of 1902-3, and observ'ations the following 

 midsummer showed the new growth in all the trees to be distinctly 

 resetted (PI. XXVIII, fig. 2). 



In like manner three 7-year-old trees were severely cut back, or "de- 

 homed," and five other badly diseased trees were cut back to a stub 18 

 inches high. This work was carried out in February, 1912, in the orchard 

 of Mr. G. W. Saxon, Tallahassee, Fla. The following spring most of 

 the new growth was vigorous and the leaves were dark green and normal 

 in appearance. Toward midseason, however, the leaves began to appear 

 yellow mottled and those most recently developed were undersized; 

 before the end of the season every tree and nearly every shoot was badly 

 affected with rosette. 



In the summer of 191 1 three badly diseased trees belonging to the 

 Standard Pecan Co., Monticello, Fla., were cut back to the trunk. The 

 following midsummer all the new growth was resetted as badly as before 

 cutting back. 



Further observations have been made upon the effect of severe pruning 

 and cutting back in orchards at Belleview, St. Augustine, Monticello, 

 and Tallahassee, Fla. ; Thomasville, Baconton, and Albany, Ga. ; and at 

 Orangeburg, S. C. In all cases the same negative results have occurred. 

 Usually in vigorous trees the new growth appears healthy, as in the case 

 of resetted trees severely cut back by the disease itself; but before the 

 end of the summer or at least by the next season the rosette again 

 appears. The disease was in no case eliminated by pruning. 



TRANSPLANTING EXPERIMENTS 



In order to determine whether the cause of the disease was to be sought 

 in the tree itself or in the soil, several transplanting and germination 

 tests were carried out. 



In December, 1902, 8 badly resetted trees were dug up from the J. B. 

 Wight orchard at Cairo, Ga., and healthy seedling nursery trees were 

 immediately set in the holes. At the same time 41 nursery trees were set 

 in vacant places where no trees of any kind had been growing for one 

 or more years. The following August, i tree out of the first group 

 and 8 out of the second were dead, probably from eff'ects of transplant- 

 ing. All the remaining trees were apparently in a normal condition. 



