Adult flatheaded borers are fast-moving, flattened, metallic-colored beetles with short antennae. Larvae are whitish, legless, and the first segment of their thorax is wide and flat just behind the head. They make winding tunnels beneath the bark, destroying phloem and cambium and girdling the trunk or branches. The tunnels may be visible externally as spiral ridges or cankers on the limbs or trunks.
Unlike clearwing borers, which expel frass from cracks in the bark, flatheaded borers pack their fine, sawdust-like frass in their tunnels. Adults emerge from infested trees in spring or summer through characteristic D-shaped holes. With some species such as the flatheaded appletree borer , the bark becomes cracked or cankered at the site of attack. After mating, female borers emerge and lay their eggs on the bark of their preferred host trees. Unlike young clearwing borers, newly hatched flatheaded borers do not crawl over the bark in search of entry points.
Instead, they chew directly into the tree through the bottom of the egg shell. Systemic insecticides applied via trunk injection, basal bark sprays, or as a soil drench are effective against flatheaded borers and they may be the only practical method for treating tall trees. Newly-transplanted ornamentals and nursery liners can be protected with properly-timed bark sprays of the same types of pyrethroids listed above for clearwing borers.
This invasive insect, which has killed hundreds of millions of ash trees in North America, was discovered in Kentucky in The larvae feed on the inner bark of ash trees from June through October, disrupting the tree's ability to transport water and nutrients.
Unless protected, infested trees usually die within 4 to 7 years of attack. All native ash species are susceptible to attack. The insect has been found recently in white fringetree Chionanthus virginicus.
Ash trees can be protected from attack by this devastating insect by: 1 a systemic insecticides applied by soil injection or soil drench dinetofuran, imidacloprid , 2 systemic injections applied as trunk injections azadirachtin, emamectin benzoate, imidacloprid , or 3 a systemic insecticide applied as a lower trunk spray dinetofuran.
Options vary with tree size diameter at breast height. Homeowners may use products that contain either dinetofuran or imidacloprid. Bronze birch borer Agrilus anxius is a severe pest of white or paper birch in the landscape. With successive years of attack, the tree becomes progressively weaker until it is killed. Dead or dying limbs will have numerous D-shaped adult exit holes, each about the size of a BB shot. In Kentucky, adults begin emerging and laying eggs in mid-May.
The flatheaded appletree borer , Chrysobothris femorata , is a severe pest of small, stressed landscape trees, especially flowering crab apples, hawthorns, and maples during the first year or two after they are transplanted. This borer may attack almost any hardwood tree that is stressed by defoliation, sun scald, drought, soil compaction, or mechanical injury.
It makes broad winding tunnels under the bark, destroying the phloem, cambium, and outer xylem. The full-grown larva is about an inch long, legless, and yellow-white. A single borer can girdle and kill a small tree. The adults emerge and begin to lay eggs in late May or early June in Kentucky.
Stressed trees and shrubs tend to be more susceptible to borer infestation, so plant health care is a first line of defense:. Mention or display of a trademark, proprietary product or firm in text or figures does not constitute an endorsement and does not imply approval to the exclusion of other suitable products or firms.
The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication. Insect Borers of Trees and Shrubs. Potter and Michael F.
Potter, Entomologists University of Kentucky College of Agriculture Wood-boring insects are among the most destructive pests of ornamental trees and shrubs. Infestation and Damage Borers rarely infest healthy plants growing in their natural environments. Clearwing Borers Adult clearwing borers are delicate, day-flying moths that resemble small wasps. Detecting Clearwing Borers Early signs of clearwing borer infestation are wilting of terminal shoots, and branch and crown dieback.
Figure 1a. Symptoms of clearwing borer infestation include crown dieback. Figure 1b. Share your gardening joy! There are many insects that can be described as borers. The insects that bore into the seasoned timbers of furniture and houses are different species to those that bore into trees. The most common borer insects found in gardens are the larvae of Longicorn Beetles.
Larvae of Jewel Beetles are also quite common in gardens. Wood boring moth larvae may also be of concern in gardens, including the larvae of Wood Moths and the Fruit-Tree borer Maroga melanostigma. All these borer insects have something in common - most of their life cycles are completed out of sight inside their target plants. The secret to pest control is to keep an eye on your plants, so that you can detect pest incursions early.
Any control method you use is always going to be more effective if you detect pests early i. Keeping an eye on your plants is paramount with borers because by their very nature, borers are hidden inside the plants.
You are most likely to see the tell-tale signs of borer activity see Symptoms of Borer Activity below before you see the insects themselves.
Some borers are more damaging than others so identifying them is very important. For example, Jewel Beetle larvae prefer to feed in weakened or damaged trees. In other words, if you find Jewel Beetle activity in one of your trees, that is a sign the tree may not have been in great shape in the first place. If borer damage occurs regularly in wattles in your garden perhaps you could try planting less susceptible species such as Cedar Wattle. You should also consider removing any infested wattles to break the life cycle of the borer insects and prevent a new generation emerging.
Alternatively, as a fast acting liquid fertiliser that can be applied to the leaves and soil, try Yates Dynamic Lifter Liquid.
Longicorn Beetles aka Longhorned Beetles are members of family Cerambycidae. There are about 1, species native to Australia, and some species are common borers in home gardens.
Longicorn Beetles are not necessarily pests. Most species attack weakened, dying or dead trees and as such are part of the decomposition cycle.
Jewel Beetles are members of the family Buprestidae and there are about 1, species native to Australia. Their bright colours make them the most recognisable of all beetles. Jewel Beetle larvae are wood borers, but once again most species are not pests as they tend to attack unhealthy trees.
Wood Moths also known as Goat Moths are members of the family Cossidae. There are about species native to Australia, but only about half of them have been formally described.
There are more than 5, species of moths in the family Oecophoridae. The most common wood borer in this family encountered in gardens is the native Fruit-tree borer Maroga melanostigma, which is found in all states of Australia. Compared to other borer pests, the damage caused by this moth is minor. Larvae of common Longicorn Beetle species are 30 mm to 50 mm long.
Jewel Beetle larvae are legless creamy grubs, with a wide flattened thorax and a long body giving them an almost cobra-like appearance. Wood Moth larvae are usually very large from 50 mm to mm long, and yellow, grey or pink in colour depending on the species. Larvae are mostly hairless with armoured thoracic segments and brown heads. Fruit-tree Borer larvae are pale pinkish brown caterpillars with brown heads and they grow to about 50 mm long.
Adult Jewel Beetles are mostly brightly coloured metallic beetles from 2 mm to 60 mm long. Adult Wood Moths are usually large grey or brownish moths. Once they leave, they leave exit holes ranging from 0. Powderpost beetles feed mainly on the starch content of deciduous trees, both hardwood and softwood, depending on the species. This type of wood-boring beetle Calymmaderus incisus is, unsurprisingly, native to and primarily found in south-eastern Queensland.
Along with the pine bark anobiid Ernobius mollis and a few other species, they form the anobiid beetles family. The adult Queensland pine beetle is around 3 mm long and 1. Its colour is a warm, reddish-brown, and it has a shiny exterior and antennae with a 3-segment club. Its legs are usually tightly folded next to its body. When leaving the timber, the Queensland pine beetle leaves behind 2 mm wide holes. As with most kinds of wood borers, this species hatches in a few weeks, lives a 3-year-long larval life, and lasts up to 4 weeks as an adult beetle.
This wood-boring beetle, once again unsurprisingly, infests hoop pine sapwood almost exclusively. It attacks mostly wooden housing structures, such as floorboards and walls, and can sometimes be found in furniture. Older homes are more susceptible to attacks, and the damages are usually heavier.
The damage caused by Queensland pine beetles is easily recognised by its honeycomb appearance. This pesky wood borer Heterobostrychus aequalis is known to be a nuisance pretty much anywhere except Western Australia and is pretty hard to detect. The adult auger beetle has a long, cylindrical body that reaches mm in length and For the lesser auger beetle, any seasoned hardwood item is fair game.
It mostly wreaks havoc on timber with a high sapwood and starch content, be it furniture or a housing structure. This type of wood-boring beetle Hylotrupes bajulus is known around Australia as a European house borer. However, you can see it referred to as a longhorn beetle or an old house borer, too. This beetle usually grows up to mm.
In some cases, the antennae and legs can have a reddish hue. The complete lifespan of the European house borer can range from 2 years to an entire decade!
The type of wood, the amount of moisture, the temperature, etc. When exiting the timber, the adult beetle leaves exit holes around mm in size. European house borers like to munch on the sapwood of softwood, pine, fir, and spruce. Still, they can attack older wood, too, and the damage is usually more severe.
This wood borer is somewhat similar to the jewel beetle Buprestidae , commonly known as a metallic wood-boring beetle due to its highly shiny body and iridescent colours.
However, jewel beetles prefer to feed on various plants out in nature, mostly dying tree branches. Not sure what kind of wood borer you are dealing with? Get in touch and we can help identify and get rid of it!
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