writes:
Kathy Shaner is quick to point out the importance of sealing all pruning
wounds on pyracantha, especially with the problems associated with
fireblight, which she said can be transferred from one plant to another
by the movement of birds and insects.
With respect to Fireblight, I am not sure that sealing wounds is a major
preventative step. . . I could be wrong. Nina?

For the Firethorn Enthusiast who may confuse Fireblight with Pyracantha Scab:

Fireblight. Flower clusters wilt and turn black. The foliage looks blackened
and scorched, and die back occurs. In spring and summer during humid weather a
white ooze may exude from infected wood. Another check is to peel back the
bark to see whether the area is streaked reddish brown.

Fireblight is a bacterial disease spreading backwards along the stems. It is
spread by wind-blown rain and insects to the branches of the tree. Infected
branches are killed quickly and a tree can die into two or three years unless
prompt action is taken.

If your bonsai becomes infected, prune out infected areas. Infected wood is
stained below the branch bark. You need to cut back into healthy wood well
below the last sign of staining. To prevent contamination, wipe pruning tools
between cuts with a rag soaked with horticultural disinfectant (Jeyes fluid) or
methylated spirit to prevent spread of the bacteria. It is advisable to destroy
the plant if it is small or the attack severe.

Pyracantha Scab. Dark green to black spots appear on leaves and twigs in
early summer, causing leaf fall. Scabby patches appear on fruits later in the
autumn, spoiling their appearance. The berries may also split and fall off. The
disease can be confused with fireblight, which also occurs on Pyracantha;
however, fireblight causes a more sudden wilting and shrivelling of the shoots.

Prune out and dispose of infected twigs. If done early in the year, pruning
will reduce colonization of the later flowers and berries and prevent the
disease overwintering.

Nina may be able to recommend a chemical treatment, if such a solution exists.

Cordially,

Michael Persiano
members.aol.com/iasnob

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