disease attacks the
fruit, leaves and twigs. The husks of the diseased nuts become
covered with dark spots or specks. They become hardened and
crack open in places. As a result of the attack, growth is
stopped, the fruit does not fill out and mature, but drops
prematurely or, in some cases, remains attached to the trees
long after the leaves have fallen. Round, black spots form on
the leaves when attacked by the fungous. These become dead and
brown and in most cases the whole leaf is destroyed. When
attacked, the trees are usually so badly injured that they make
little progress. Not all varieties are subject to the disease
in the same degree and some appear to be entirely exempt.

[Illustration: _Photo by H. A. Gossard._

FIG. 36. Spraying Pecan Trees.]

Those varieties which are not attacked should be given
preference in propagating work. The disease may be further
controlled by spraying with Bordeaux mixture, as directed under
leaf-blight.

PECAN ROSETTE: [L]"The earliest symptoms are a peculiar
crimping of the leaves at the ends of the branches. These
leaves are smaller with crimped margin, and when held to the
light show light green or yellow streaks between the veins. The
leaf tissue in these light-colored areas is thin and
undeveloped and often breaks away leaving angular holes in the
leaves. A tree usually shows the disease over the whole top at
once, though sometimes only a single branch is affected at
first. As the disease progresses, the foliage assumes a bunched
appearance, due to the formation of tufts of leaves at the ends
of the branches. This characteristic has led us to use the term
"Rosette" as a name for the malady.

"The next stage of the disease which is observed the second
year or later, is a dying-back of the branches from the tips.
This is followed by the development of numerous small, lateral
branches from adventitious buds. These are short, producing
thick clusters of small, unhealthy leaves, sometimes reduced to
mere skeletons, so that the rosetted appearance of the tree is
intensified. This goes on from year to year. The growth of the
tree is checked and these abnormal branches are formed only to
die back each year. Trees in the earliest stages of rosette
have been observed to have light crops of nuts, bu