Why Are They a Problem?

The peach twig borer is a common pest of peaches in the Okanagan Valley. It damages small terminal shoots as well as buds and developing leaves. Shoot damage is distinct and appears as wilting or “flagging” of terminal growth. Fruit damage may also occur, appearing as small pin‑prick holes that ooze a clear or light amber exudate. This damage can render fruit unmarketable.

The peach tree borer is another common pest of cherries, peaches, apricots, and plums in the Okanagan. Larvae bore into the base of the tree, weakening its structure, reducing crop production, and in severe cases causing girdling.

The resulting wounds often exude sap and can act as entry points for secondary pests and diseases.

Where Do These Pests Come From?

Peach twig borer larvae overwinter under bark or in limb crotches. In spring, they enter shoots and continue feeding, causing the characteristic flagging symptoms. Peach twig borer produces two generations per year. The first generation occurs in May and June, with a second generation developing later in the season in July. Later generations may feed on shoots or immature fruit.

Peach tree borer larvae overwinter at the base of trees, often producing a mixture of frass, sawdust, and gummy exudate. Once mature, adults emerge and lay eggs on bark, where larvae enter through cracks. Peach tree borer has one generation per year.

How the BC DAS System Helps

The BC DAS system helps growers track the development of peach twig borer populations based on local conditions. Using degree‑day accumulation along with temperature data from selected weather stations, the system provides predictions for egg hatch timing and adult flight periods. These insights help growers identify optimal timing for control measures, including mating disruption using pheromone traps.

Control options are incorporated into the BC DAS Peach Twig Borer model. The DAS Spray Guide provides spray options, rates, and timing information for effective coverage. The guide also allows growers to select products registered for conventional or organic use. By following the model, growers have access to timely information to support effective management decisions.

For more information, check out the BC Tree Fruit Production Guide (Peach Tree Borer or Peach Twig Borer)

Learn More (Video)

Interested in finding out more? Check out the BC DAS Peach Twig Borer and Peachtree Borer model video to connect field observations with the online DAS system.