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Peach Twig Borer (Anarsia lineatella) and Peach Tree Borer (Synanthedon exitiosa)

Wednesday May 20, 2020

Peach Twig Borer damage on peach shoot
Larvae of Peachtree borer from a cross secton of wood

Peach Twig Borer (Anarsia lineatella) and Peach Tree Borer (Synanthedon exitiosa)  

Why are they a problem?
The Peach twig borer is a common pest of peaches in the Okanagan Valley, damaging both the small terminal shoots as well as the buds and developing leaves or peach trees. Shoot damage from the Peach twig borer damage is distinct in that it is characterized by a wilting or a 'flagging' of the leaf tissue on the terminal ends of the branches. Damage can also occur on fruit as small 'pin pricks' which ooze a clear or light amber coloured exudate, making the fruit unmarketable in many cases.
The Peachtree borer is another common pest of cherries, peaches, apricots and plums in the Okanagan. Damage from the Peachtree borer includes the actual 'boring' into the base of the tree which compromises the trees' growth and crop bearing capacity, as well as its overall health by weakening it at its base, even leading to girdling in more serious cases. Once affected, the open gummy wounds can also serve as vehicles for infections by other pests and diseases.  
 
Where do these pests come from?
The Peach twig borer larvae overwinter as larvae under cracks in the bark of peach trees or in the crotches between limbs. In the spring, these larvae will enter into the actual shoot and continue to feed, which leads to the characteristic wilting of the leaves on the limb. The Peach twig borer has 2 generations per year, meaning that there are 2 rounds of larvae being produced in one growing season, with the first generation being present in May and June. Adults of this first generation will lay their eggs until mid to late May and into June, with the second generation of the Peach twig borer larvae developing in the shoots or in the immature fruit, appearing later in the summer in July.
Larvae of the Peachtree borer overwinter at the base of the peach tree, normally exuding a mixture of frass and sawdust, and an amber coloured ooze or 'gumming'. Once mature, adults will fly and lay eggs onto other trees, where the larvae will enter into a tree by way of feeding through cracks in the bark. The Peachtree borer has only 1 generation per year.  
 
How the BC DAS system can help: Keeping you Informed + Equipped
The BC Das system allows growers to be informed about the larval development of Peach Twig borers in the growers' specific geographic location. Using information on degree days, as well as maximum and minimum temperatures and DDC from the local weather stations that the grower has selected as being reflective for their orchard, the BC DAS system provides the grower with up to date information regarding the various stages of Peach twig borer, including the predicted egg hatch date and when adults will most likely be flying. The combination of pulled weather information and the upcoming forecast will prompt the system to send out notifications to alert growers for when control measures are best suited for use, including optimal timings for mating disruption using pheromone traps.  
 
In addition, the BC Das system has control measures incorporated into the Peach twig borer model webpage. The DAS Spray Guide offers different spray options, rates and timings, allowing growers to plan their sprays for coverage, as well as allowing the grower to select for product options currently registered for either conventional or organic use. By following along on the BC DAS model, the grower will have timely information and knowledge of the tools currently available to control Peach twig borer populations in their orchard.  
 
Still interested in finding out more? Check out our BC DAS Peach Twig Borer and Peachtree Borer model video on YouTube to connect horticultural knowledge from the field with the online DAS program: