The Cypress Bark Weevil (Aesiotes leucurus) in Adelaide
A common pest in South Australia that attacks a variety of conifers, with the first signs of attack being loss of foliage, colour and dieback of branches.
Trees that succumb to the pest are usually under stress from other causes, such as lack of water or harsh pruning.
Adults are approx 20mm long, dark grey/brown, and lay eggs under the bark of the tree. When the larvae hatch they feed under the bark in the phloem-cambial region, often ring barking the affected area.
The legless larvae grow to approx 20mm long before pupating in a hollow created in the sapwood. The adult emerges through a 6mm diameter hole bored through the bark.
The invasive species Cypress Bark Weevil
Characteristics of the Cypress Weevil
Appearance: Cypress Bark Weevils are small beetles, typically dark in colour, with a body length approx 20mm. They have a distinctive snout and elbowed antennae, typical of weevils.
Life Cycle: They undergo a complete metamorphosis, starting from eggs, then to larvae, pupae, and finally to adults. The particularly harmful larvae are legless and feed under the tree's bark.
Diet: Both larvae and adult Cypress Bark Weevils feed on plants.
Cypress Weevil infestation in row of Pencil Pines.
Die back of numerous small branches indicate early infestation. Weevil ring barks individual twigs causing them to die. In extreme cases the main stem can be ring barked causing that portion of the tree to die. Often the tops of affected trees will snap off if the wood structure is severely compromised.
Weevil Impact in Adelaide
Damage to Flora: In Adelaide, the Cypress Bark Weevil poses a threat to a wide range of ornamental plants and native species. Their feeding can lead to yellowing of leaves, reduced plant vigour, and even death of plants.
Water stress can lead to weevil attacks. Plants under stress from lack of water are more susceptible to weevil attack.
Control Measures: Managing the weevil population is challenging due to their nocturnal habits and the underground lifestyle of the larvae. Control methods include the use of insecticides, biological control agents, and cultural practices like removing plant debris that provides shelter for the weevils.
Invasive Species: As an invasive species, the Cypress Bark Weevil disrupts local ecosystems in Adelaide. Its unchecked population growth can lead to imbalances, affecting plant life and other species that depend on those plants.
Adaptability: These weevils have shown a remarkable ability to adapt to various environments, making their control more challenging.
In summary, the Cypress Bark Weevil in Adelaide is a notable concern due to its invasive nature and the damage it causes to various plants. Effective management and control strategies are essential to mitigate its impact on the local environment and biodiversity.
If you suspect a Cypress Bark Weevil infection, contact Steve on 0418 821 642 or by sending us a message so we can arrange to eradicate these pests for you.