6 
Bulletin 69 . 
That the trees are injured by water under these circumstances 
cannot be doubted, since no agricultural plant can thrive in a sat¬ 
urated soil. We have not yet demonstrated the exact relation which 
fungi bear to this condition, but it is evident that they play an 
important part in the destruction of the trees. Certain species are 
usually found on the roots of diseased trees and attacking healthy 
tissue. Moreover, young trees have been known to be killed in one 
season, apparently by root rot, when planted in the places from 
which dead trees had been removed. 
This subject is a most perplexing and important one, and one 
that is as yet but little understood. We expect, however, to make it 
one of the principal lines of investigation of this Section for the 
coming season. In the meantime certain sanitary measures may be 
mentioned that might well be observed by many orchardists. 
When it becomes evident that too much water is being used in 
irrigating, as is indicated by yellow foliage, or by the raising of the 
level of the water in the soil, more use might well be made of the culti¬ 
vator. By keeping the surface of the soil loose much of the water 
is prevented from evaporating, thus lessening the necessity of fre¬ 
quent irrigation. The trees should be kept in a thrifty condition, 
and yet not allowed to make a rapid growth, which produces soft 
tissues that easily succumb to attacks of blight. On some soils it 
may be best to keep the orchard seeded to alfalfa, but usually better 
results will follow a systematic use of cover crops. The many 
advantages to be derived from the use of cover crops cannot be dis¬ 
cussed here, but with this system of cultivation some crop is sown in 
the orchard in late summer or early fall which is plowed under the 
next spring. Mr. Griffin has found that the best leguminous plant 
for this purpose at Rocky ford is hairy vetch. (See Bulletin No. 68 
of this Station). Since this plant is one of the nitrogen gatherers it 
may not be advisable to use it on all soils; in such cases winter rye 
may be used instead. In localities where the attacks of blight are 
severe, it may be advisable not to plow the crop under till late in 
the spring and thus avoid a rapid early growth of new wood. 
APPLE TREE ROSETTE. 
A peculiar condition of apple trees was brought to our attention 
on Rogers Mesa in Delta county by the Horticultural Inspector. 
More or less of the trouble occurs in a number of orchards in this 
locality, consequently it is a matter of considerable interest in the 
county. Some of the trees are dying, while there are a number of 
dead limbs on others, but the characteristic feature of the disease is 
a tuft or rosette of small leaves at the end of branches that are other¬ 
wise nearly bare of foliage. (See Plate II.). The similarity of this 
condition to the peach tree rosette, a common disease in portions of 
