Borers of Large Branches, Stems, and Trunks
Borers of Large Branches, Stems, and Trunks
Several insects develop by tunneling into the trunks and/or branches of trees and shrubs. Among the most important are the 'clearwing borer' moths (Family: Sesiidae) the metallic wood borers/flathead borers (Family: Buprestidae) and the longhorned beetles/roundheaded borers (Family: Cerambycidae). Most damage typically results from girdling of the cambium causing decline and die back. Some borers, notably the roundheaded borers, can tunnel extensively through the wood and cause structural weakening.
Most borers are only capable of successfully attacking dying or stressed trees. Proper watering and care is the first-line approach for prevention of borer injuries. Good cultural practices can also allow an infested tree to better tolerate borer injuries.
Insecticidal control approaches require applications just prior to egg laying and egg hatch. The occurrence of these life stages vary with different borer species and often last a month or longer. Consequently, repeat applications are often necessary for control. After eggs hatch and young borers have moved underneath the bark, insecticide treatments are ineffective. Pheromone traps are available to aid in the timing of treatments for control of clearwing moth borers (peach crown borer, lilac/ash borer).
Currently, chlorpyrifos (Dursban), permethrin (Astro) or carbaryl are recommended for control of wood borers. These materials are used as coarse sprays applied to the trunk until point of run-off. Lower branches and the crown area may need protection, depending on the habits of the borer. Spray deposits typically last for several several weeks to months; insecticide degradation is much slower on coarse bark (e.g., elm) than on smooth bark (e.g., birch). Soil and trunk injected insecticides provide irregular control of wood borers, at best, particularly where injuries have already occurred which affect translocation of the insecticides to the borer feeding sites.
Specific recommendations for control are included in the supplement with sections related to wood borers including: Zimmerman pine moth, Pinyon pitch mass borer, Lilac/Ash borer, Peach tree borer, and Bronze birch borer.
| Flight Periods and Hosts of Common Woody Plant Borers in Colorado | |||
| METALLIC WOOD BORERS (Coleoptera: Buprestidae) | |||
| Scientific name | Common name (if any) | Common Hosts | Typical Flight Periods |
| Chrysobothris femorata | Flatheaded Appletree Borer | Apple, maple, Populus, other hardwoods | June-August |
| Agrilus anxius | Bronze Birch Borer | Birch | June-July |
| Agrilus difficilis | Honeylocust Borer | Honeylocust | June-July |
| Agrilus politus | Willow, Populus, many hardwoods | June | |
| Agrilus aurichalceus | Rose Stem Girdler/Bronze Cane Borer | Caneberries, rose, currant | late May-June |
| Chalcophora species | Pines | June-August | |
| Dicerca species | Aspen | June-August | |
| LONGHORNED BEETLES (Coleoptera: Cerambycidae) | |||
| Plectodera scalator | Cottonwood Borer | Populus, willow | July-August |
Megacyllene robiniae |
Locust Borer | Black locust | August-September |
| Saperda calcarata | Poplar Borer | Populus, willow | June-August |
| Saperda inornata | Poplar gall borer | Poplar, cottonwood | July-September |
| Parandra brunnea | Pole Borer (Aberrant Wood Borer) | Maple, other hardwoods | July-September |
| Neoclytus acuminatus | Redhead Ash Borer | Ash, other hardwoods | April-June |
| Monochamus species | Pine Sawyer | Pines, spruce, fir | May-Sept. |
| Callidium antennatum | Blackhorned Pine Borer | Pines, other evergreeyns | May-June |
| Callidium texanum | Juniper | May-June | |
| Atimia huachuchae | Juniper borer | Juniper | June-July |
| Dorcaschema alternatum | Small mulberry borer | Mulberry | June-July |
| Moneilema spp. | Cactus Longhorn | Cholla cacti | June-July |
| WEEVILS (Coleoptera: Curculionidae) FALSE POWDERPOST BEETLES (Coleoptera: Bostrichidae) |
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| Cryptorhynchus lapathi | Poplar and Willow Borer | Willow, poplar | July-August |
| Pissodes strobi | White pine weevil | Spruce, some pines | March-May |
| Amphicerus bicaudatus | Apple Twig Borer | Honeylocust, apple, grape, ash and many other deciduous trees | June-July |
| CLEARWING BORERS (Lepidoptera: Sesiidae) | |||
| Podosesia syringae | Lilac/ash borer | Ash, lilac, privet | April-June |
| Sesia tibialis | Cottonwood Crown Borer/American Hornet Moth | Cottonwood | mid June-July |
| Synanthedon exitiosa | Peach tree Borer (Crown Borer) | Prunus | mid June-September |
| Synanthedon tipuliformes | Currant Borer | Currant, gooseberry | late May-June |
| Synanthedon viburni | Viburnum borer | Viburnum | June-July |
| Synanthedon novaroensis | Douglas-fir pitch moth | Spruce, some pines, Douglas-fir | June-July |
| CARPENTERWORMS (Lepidoptera: Cossidae) | |||
| Prionoxystus robiniae | Carpenterworm | Elm, maple, ash | June-July |
| DIORYCTRIA BORERS (Lepidoptera: Pyralidae) | |||
| Dioryctria ponderosae | Pinyon "Pitch Mass" Borer | Pinyon, ponderosa pine | June-August |
| Dioryctria zimmermani | Zimmerman Pine Moth | Austrian, Scots pine | August-September |
| NOCTUID BORERS (Lepidoptera: Noctuidae) | |||
| Achatodes zeae | Elder Shoot Borer | Elderberry(Sambucus) | July, August |
| HORNTAILS (Hymenoptera: Siricidae) | |||
| Tremex columba | Pigeon Tremex | Maple, elm other hardwoods | late July-August |
| STEM-BORING SAWFLIES (Hymenoptera: Tenthredinidae) | |||
| Hartigia trimaculatus | Rose Stem-Boring Sawfly | Rosa, Rubus | late April-May |
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