TREES AS GOOD CITIZENS 
176 
shaped top, and the stems are swollen at the base. These 
two characters often are unreliable as the ring is frequently 
evanescent and the swollen base usually is not very pro¬ 
nounced. Trees which are badly afflicted with this form 
of rot should be cut down, and it is not safe to replant in 
the infected soil. 
Coral red spots about the size of a pin’s head on the 
bark of trees and shrubs are symptoms of a disease com¬ 
monly called Nectria Cinnabarina canker, a fungous 
growth closely related to the rusts of leaves, which finds 
entrance through small surface wounds. It produces bluish 
or blackish streaks in the wood. Once established, it has 
a tendency to spread to other trees or plants. This disease 
may be cured by cutting and burning all affected bark 
and wood and washing the wound with solution of copper 
sulphate, using 1 pound to 5 gallons of water. The exposed 
surface should then be coated with coal tar. As with 
other diseases, prevention is better than remedy, and if all 
wounds are promptly treated when created, the spores will 
find no means of entry. 
Black knots sometimes appear on twigs and leaves of 
Cherries, Plums and allied trees but rarely on shade trees. 
While they are not serious, they are unsightly. They may 
be controlled by cutting and burning in the early fall and 
spraying with either copper sulphate or lime sulphur before 
the buds open in the spring. 
“Witches’ Broom” is a conspicuous growth which is 
frequently seen and which impairs a tree’s appearance. It 
consists of masses of short twigs, so bunched as to cause 
them, in some instances, to be mistaken for mistletoe. This 
disease is caused by a fungus or an insect, often a mite. 
It may be controlled by cutting and burning the affected 
parts. Although mistletoe is a parasite plant it is not a 
fungus, but belongs to the group of flowering plants to 
