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Calgary, Alberta
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Oystershell scale

Oystershell scale

The oystershell scale is a sneaky and dangerous insect pest that gouges on shade, hedge and shrub crops. The damage they cause only gets noticed when the condition is too late. The pest, which is an armored scale, is one of the most common of its kind with more than100 cropsbeing susceptible to it.

The oystershell scale, which is not native to Calgary, has been spreading uncontrollably since its introduction as they enjoy the dry springs and warmth conditions that comes with the region. Cold and rainy weather usually slows them down.

The armour scale is arguably the most challenging aspect about pest control in this city with many pesticides becoming quite ineffective against them. Also, other friendly predators have failed to reach at them.

Furthermore, they are rarely noticeable until their infection on a given plant is quite severe. At this stage the probability that the pests will kill the plant increases, unless the action taken is efficiently high. This has pegged the need to fight them at their early stages as it threatens hedges and other plants in Calgary.


So how do you know your hedges have been infected by this pest? The most notable sign is the appearance of distinctive bumps looking like oyster shells on the bark of the crops. If the infection is severe, branch dieback may be observed and gaps will start appearing within the hedges. Leaves may also start turning yellow. If care is not taken, the whole plant might eventually die.

Treatment and control

The most notable trait about this pest is its reproductive cycle. After building the armoured shells, these pests do not move and, as was noted, become harder to combat.

However their hatchlings, called crawlers are more susceptible to pest control. Their mobile nature makes them an easy target for predators and insecticides.

So how do you time them? As was mentioned earlier, the pest’s reproductive cycle is its primary weakness and since they lay eggs once a year, which hatch in early June, it makes it possible to track these vulnerable crawlers

Now that you know about the Oystershell scale pest, let us consider the alternatives you have of controlling them. Remember that it is harder to deal with the adult pest that has already settled into the bark of the plant. It is for this reason that you are advised to prunebranches that have been infected. If the whole crop has been infected, you can cut off the severe parts and hope that the remaining part is able to bounce back. However, if the situation is dire, this option may not be effective and getting rid of the whole hedge is inevitable.

Another option is to water your plants and give them proper nutrition to ensure they are strong enough to bounce backfrom the attack. Since the bugs suck fluids from the plant, providing a means for the plant to replenish may give it what it needs to survive the ordeal. However, this initiative will only be as effective as complementary efforts you put into reducing infection levels and killing off the pests.

Lastly, timing the crawlers would help to prevent the population of the pests from growing and replacing dead ones. Once Oystershell scale crawlers have been spotted, use insecticides or natural predators to kill them off. Remember that pesticides are poisonous and should be handled with care.

Now that you know how to deal with the oyster shell pest, you can be able to protect your hedges in Calgary. Remember to keep checking your hedges for signs of infection. Cotoneaster are the most affected hedge so you may want to choose another variety of shrub for your hedge. Click here for other great options for Calgary hedges