147 
early stages of tlie disease, which is by no means the case. As a rale, 
beetles of this group prefer sickly trees. Late in the season many such 
trees were riddled by Scolytus , but they did not appear in numbers 
until June. The time to make such an examination is in the spring 
when the disease first appears and not in summer or autumn when the 
trees are nearly dead. In spring, when the cause of this rosette dis¬ 
ease is very active, the Scolytus rugulosus can do no harm, because it 
is then undergoing transformations in the trees which were attacked 
the previous year. Larvm and pupre were taken from a number of such 
trees. They were generally in winding passages in the wood, and were 
most abundant in some plum trees not suffering from this disease. 
Moreover, repeated observations in Kansas during a two-weeks’ visit 
failed to discover a trace of this insect. Neither had the Experiment 
Station entomologists ever seen it. The probabilities, therefore, are that 
this species has not yet appeared at Manhattan. 
The Scolytus rugulosus does not cause this disease, nor do I think it 
due to any other insect. Whatever be its cause, the disease is evidently 
increasing, and peach-growers should be on the alert to destroy it as 
soon as it appears. The affected trees should be dug out and burned 
as soon as discovered. The contagious nature of the disease is now 
beyond dispute, and it is not wise to let them remain a single day. 
EXPLANATION OF PLATES. 
Plate VIII. Healthy peach tree from an orchard of bndded fruit near Griffin, Georgia. 
Set 21 years. This tree stood upon cultivated, level, fertile “mulatto 
land.” Photo, June 28, 1890. 
Plate IX. Tree attacked by the rosette—a typical case. This tree stood in the same 
orchard as VIII and not over 20 feet distant. It was healthy in 1889. 
Photo, June 28, 1890, at which time it did not bear a single leaf or 
shoot-axis of normal character. The bark on the trunk of this tree 
had been injured by a borer (Algeria exitiosa , Say) but over an area not 
larger than a silver dollar. There were no other injuries by borers; 
no bruises, and no boriugs by Scolytus anywhere on the trunk or main 
limbs. To determine the amount of twig injury attributable to Sco ¬ 
lytus , I examined each one of the several thousand tufted and growing 
shoot-axes, and all of the internodes, finding three beetles and fifty 
slight injuries. All these were of recent date, and many did not reach 
into the cambium. There were no larvm and no winding passages 
under the bark. Usually the gnawings were at the base of the tuft 
on the upper side in the acute angle formed by the shoot and the older 
stem. These injuries were generally vertical and seldom over one- 
eighth of an inch long or broad. In no case was a twig of the previous 
year’s growth girdled or so injured as to affect shoots above the boring. 
The worst injuries amounted simply to the killing of the particular 
shoot-axis bored into. These had dried up and were easily distin¬ 
guishable from the uninjured majority. The fact that the dead shoots 
were nearly as large as the rest showed clearly that the injuries were 
of recent date, whereas the tree had been diseased throughout for sev¬ 
eral months, i. e., ever since it began to grow in the spring. The fifty 
injuries by the beetles were not more serious than would have been a 
like number of stabs with an awl. Later in the season no doubt the 
tree might have been full of beetles and larv«3. 
