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.

Types of Insects

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