aggregating pheromones pheromone released by either or both sexes of an insect which attracts both males and females to a given location. Used by bark beetles to ensure that sufficient beetles attack a susceptible tree to overcome its resistance.
baiting: grid placement of aggregating pheromones throughout a target stand on a 50 m grid spacing to contain emerging beetles within the stand and prevent spread to adjacent susceptible areas. This technique is used to facilitate sanitation harvesting, allowing removal of a larger proportion of the beetle population at the time of logging.
baiting: spot placement of aggregating pheromones around small centres of beetle attack or around single tree treatment sites to localize the dispersal of any emerging beetles. Bait placement simplifies subsequent detection and treatment projects.
beetle management units a management area where a consistent beetle management strategy can be applied. Usually, BMU boundaries will coincide with other administrative or operational boundaries.
boring dust fine, light-coloured powdered wood, cast out of tunnels made by burrowing bark beetles or other wood boring insects. An early sign of attack by bark beetles.
callow adults newly molted adult insects before the exoskeleton has hardened fully; often pale in colour.
danger rating developed by combining hazard and risk ratings for a particular stand or area. A high danger rating indicates that the area being considered is under attack by bark beetles or that attack is imminent, and that once attacked, damage will be high.
egg gallery a groove excavated by the female bark beetle under the bark. Eggs are laid in niches or groups along the side of the egg gallery. When larvae hatch, they excavate feeding galleries in the phloem at right angles to the egg gallery.
elytra hardened front wings that form a shell over the rear wings on beetles.
hazard an estimate of the susceptibility of a stand to damage, given its physical and site characteristics. Hazard is dependent on stand and site factors that are conducive to successful beetle attack. In general, the higher the hazard, the more damage will occur during an infestation.
instar any post-egg stage, initiated or terminated by molting, indicating growth stages. Bark beetles normally have four larval instars between egg hatch and pupation.
larva an individual that emerges from the egg and differs markedly from the adult form. Bark beetle larvae are white, legless grubs.
mass attack the aggregation of bark beetle adults on one host tree in sufficiently large numbers to overcome the hosts defense mechanisms.
pitch tubes a combination of boring dust, insect frass, and tree pitch that amasses around the entrance hole of an egg gallery as the adult female beetle excavates under the bark.
probe usually a systematic strip-type survey through a stand to obtain detailed information on infestation levels, history, and stand data needed to make management decisions.
pupa the stage of insect development between the last larval instar and the emergence of a new adult. Typical adult features begin to form.
risk the probability that a tree or stand will be attacked by bark beetles. Risk is dependent on the proximity of a beetle population to the stand in question. The higher the risk, the more likely a stand will be attacked.
salvage harvesting removal of trees that are dead, dying, or deteriorating to utilize remaining merchantable wood before it becomes worthless. This practice is not a beetle management tool, it does not reduce beetle populations or stand susceptibility.
sanitation harvesting removal of infected or infested dead or damaged trees, or of susceptible trees, to prevent or reduce the spread of the infestation. Sanitation harvesting is intended to remove currently infested trees where beetle life stages still remain under the bark. This is the most efficient form of beetle management. The objective is to reduce residual beetle populations available for subsequent attack within the stand or in adjacent susceptible stands.
strip attack only a portion of the circumference of the tree is successfully attacked. The tree will continue to live unless subsequent beetle attack infests the live portion.
trap tree: conventional an artificial windthrow the preferred host of spruce and Douglas-fir beetle. Trap trees are healthy, uninfested trees felled prior to the beetles flight period and left to absorb attacking insects. Conventional trap trees must be removed or treated after catching beetles.
trap tree: lethal similar in intent to conventional trap trees, but used in inaccessible areas to reduce beetle populations. Lethal trap trees are treated with a systemic insecticide prior to felling. Arriving beetles are killed as they construct egg galleries. Subsequent treatment is usually not necessary.
walkthrough a non-systematic, low intensity type of ground survey for bark beetle damage. Usually, only qualitative estimates of insect and stand data are taken. Used to make initial assessment of situations and confirm aerial survey information.