Detection and Control Flashcards
True or False question: western cedar borer has no known parasites…
False: Cedar borers are known to be parasitized by Ondontaulacus editus (Cresson), a parasitic wasp whose effect on borer populations is not fully understood due to a lack of research.
We know there is no “purple cape” treatment for cedar borers, but are there any post harvest treatments that can help control their numbers?
Burning slash would incinerate any adults or pupae left in the debris on the site, reducing the breeding population attacking trees along the margin of the cut area.
What are some stand level reforestation strategies to create unfavourable conditions for western cedar borer attack?
Do not leave any pole size or larger trees as leave trees When reforesting areas that are known or suspected to harbour cedar borer. Larger trees promote the pests breeding habits by allowing more beetles to aggregate, as well as providing stronger shelters, with ample food for the larvae.
Describe the adult of ISB.
The body is 12-20 mm in length, and 4-6 mm wide. The beetle is elongate-oval with a posterior taper. The most distinguishing characteristic of this stem beetle is the brilliant bronzed green sheen of its elytra. Use this image as a visual aid:
image source: https://sflonews.wordpress.com/2015/07/22/seeking-information-about-western-cedar-borer-a-significant-pest-of-western-red-cedar/
What is the age class of tree preferred by the cedar borer?
Pole size to mature trees are all suitable for the cedar borer. Typically the bigger the better. This long window of potential damage renders cedar silviculturally unfeasible in areas where the pest is established.
Choose the best answer: How long do cedar borer larva spend inside the host before emerging as adults?
A) 3 years
B) at least one year
C) at least 2 years
D) less than a year
The correct answer is C: Larvae will eat and grow for a minimum of 2 years before they become adults. Variables such as temperature can extend the larval stage to 3 years.
Will adults attack felled logs? Will larvae continue to damage powder worm infested logs once the tree has been felled?
Attack is said to cease once the tree has been felled. Since the larvae are generally found in the heartwood, there is no cost effective treatment that can kill the pest without damaging the wood. Sources indicate that allowing wood to become seasoned will effectively kill the larvae inside, but they would likely continue to eat until being desiccated by the dry conditions.
What do the eggs of the western cedar borer look like? Where would you expect to find an egg.
The eggs are typically whitish in colour, oblong shaped, and about 2.5 mm long. Eggs are laid in crevices or under bark scales in the crown portion of a red cedar. Eggs would be extremely hard to detect.
How can you detect powder worm in a live tree?
Powder worm does not visibly kill or injure affected trees until extreme levels of infestation, so detection on live trees is unlikely. In extreme cases, dying tops, dying branches and bare spots on the trunk. See photo:
What is a way to easily detect powder worm once a tree has been felled?
By pruning the branches from the upper trunk, any dust packed boring holes will be visible on the face of the knot. See image.
image source: http://web.forestry.ubc.ca/fetch21/Z-PDF-pest-info-folder/Trachykele%20blondeli.pdf
Where are western cedar borer infestations most likely to occur?
Powder Worm is most commonly found on warm sites having sunny aspects and particularly at exposed locations such as shorelines, selectively logged areas or borders of clear cuts.
What is a landscape feature that puts red cedar stands below 250 m elevation on the coast at decreased risk of attack? Choose the best answer:
A) Mesic sites with low stand densities.
B) Xeric sites with high stand densities.
C) Fresh sites with low stand densities.
D) Wet sites with high stand densities.
The correct answer is D: Wet swampy sites with lots of shade are at decreased risk because this pest targets warmer sites with little shade in order to maximize survival.
Are severe cedar borer infestations common?
No, Powder Worm is not often a severe issue in forest stands. However once Powder Worm is present in a stand it is very difficult to eradicate it, especially on Vancouver Island where slash burning occurs in piles as opposed to across the entire block area.
What are some common landscape patterns created by the cedar borer?
In natural conditions, aggregated patches are most common. When infestation is set in these patches can start to show signs of stress such as dying tops and branches. Another pattern that s more common in disturbed areas is the edge effect, where infestation will occur around the forested edges where trees are exposed to increased light and heat as well as potential stress factors that weaken the tree.
Because the larva are found in the heartwood, chemical control is considered economically unfeasible. However, several pesticide formulas are labelled for use against flathead borers in nursery conditions. Choose the best answer for the trade names of these chemicals:
A) Garlon and Round-up
B) NPV and BTK
C) DDT and Agent Orange
D) Discus and Dursban
The correct answer is D: Discus and Dursban have been found to be effective in nurseries, and could potentially be used to protect high value trees. As far as forest applications go, chemicals are not an effective solution.
