As
with most borer insects, the ones that attack
roses
do so by laying their eggs in the canes. After the
eggs hatch, the immature larval form feed on the
interior tissue of the cane. When they reach a
certain size, they turn into a flying form and which
finishes eating itself out of the cane leaving a
hole behind.
As you might guess,
the hole in the cane is the most common symptom of
the presence of rose cane borers. Their feeding
damages the interior of the cane often killing the
cambium layer which is the growth tissue. They also
make the stems weaker and more likely to break off.
Sometimes there is a noticeable swelling of the cane
due to the increasing size of the larvae within.
You can often reduce
the amount of infestation by avoiding damage to the
rose canes. The borer adults need a place to lay
their eggs and mechanical damage such as pruning
wounds provide an easy point of entry for the
insect.
Prevention is the key
method of control for rose borers. Avoid damaging the
plants and keep them as healthy as possible through
proper fertilization and irrigation.
One technique commonly
used by rosarians is to dab a little glue onto wounds
made while pruning. When the glue dries, it will form a
hard barrier that cannot be penetrated by the insects
when they come to try to lay their eggs.
Note: We
have provided some general information and
observations on this topic aimed at the home
gardener. Before you take
any serious action in your landscape, check
with your state's land grant university's
Cooperative
Extension
Service for the most current,
appropriate, localized recommendations.
As
with most borer insects, the ones that attack
