Insects and diseases may become serious threats to your tree’s health if they are defoliating your trees or sucking out their sap. As soon as you notice any abnormality in your tree’s appearance, you should contact Gerard at For Trees right away. He will look at your tree, determine what the infestation or disease might be and discuss appropriate action with you. Treatment depends on a variety of factors including the species involved and the extent of the problem.
Some of the most common in Central Alberta
is a highly destructive disease that attacks more than 75 different species of the rose family. It is caused by the bacterium Erwinia amylovora.This bacterial organism is native to North America and is present throughout the continent where susceptible rose family hosts are grown. In Alberta, this disease can affect many highly desirable hardy ornamentals and fruit-producing species in the rose family including apple, crabapple, cottoneaster, hawthorn, pear, mountain ash, raspberry, saskatoon berry, plum and cherry. It is particularly destructive to species that are not native to Canada such as crabapple, apple and pear.
Because this is a very infectious disease, it is important that effective control measures be undertaken as soon as possible. A severe outbreak can kill a tree in one year. There is no chemical control for fireblight, but the disease can be managed with proper sanitation and cultural practices. As soon as the infection appears, diseased twigs and limbs should be removed by pruning 25-45 cm (10-18 inches) below any sign of infection. Tools must be disinfected between each cut or the pruning may spread the disease. If you do not want to try this yourself, contact For Trees and a professional arborist will take care of this for you.
MOUNTAIN PINE BEETLE
is a native insect found in western North America. It is dark coloured and approximately the size of a grain of rice. This beetle lives most of its life in pine trees, including lodgepole, ponderosa and western white pine. In mid-summer, large numbers of adult female beetles attack new trees by boring through the bark to the sapwood. The beetles carry a blue stain fungus that attacks the tree’s resin producing tissue which prevents the tree from repelling and killing the insects. They hinder the tree’s ability to draw water and nutrients.
Until recently, the MPB was valuable to the forest ecosystem. By attacking weakened and old trees, they sped up the regeneration of a younger forest. In the past, cold winters have kept their numbers in check. Unfortunately, recent hot, dry summers in central British Columbia and Alberta have led to an increase of MPBs, while mild winters have failed to kill off the insect’s larvae.
They have destroyed millions of pine trees, over 400 square kilometres, leaving once forested areas barren. At the current rate, 80% of mature pine trees in B.C. will be dead by 2013. Lodgepole pine, B.C.’s most commercially harvested tree, has been especially targeted which has led to millions of dollars in losses. The dead trees have contributed to releasing millions of tonnes of carbon into the atmosphere.
MPB’s continue to threaten the health of Alberta’s forests despite colder winter temperatures in early 2008. The cold weather did help to slow the rate of growth of beetle populations in certain parts of the province.
To report trees infested with mountain pine beetle or to find out more information about the devastating forest pest, call 310-BUGS (2847).
BIRCH LEAF MINER
frequently attack Birch trees. This pest does not usually kill the tree, but repeated attacks over several years may weaken it and make the tree more susceptible to damage from other insects. Damage by this pest also makes the tree unattractive and reduces its ornamental value.
The damage is usually first seen in June as pale green spots on the surface of the leaves. It is caused by the leaf miner larvae feeding within the leaves. As the summer progresses, these spots become larger and turn brown and papery. If the entire leaf becomes affected it may drop prematurely. Mature larvae emerge several weeks later and drop to the ground to pupate. The adults emerge approximately two weeks later and the cycle repeats itself.
The Birch Leaf Miner is the only insect we currently recommend and provide a chemical control for. Gerard Fournier is an Alberta Licensed Pesticide Applicator, so call for more information at 403-335-8965.
We are now able to use an organic product, Tree Azin, from Bioforest, and no longer have to rely on harsh chemicals. This product is being used for the first time in Alberta and for the first time on birch leaf miner and Bronze Birch Borer. Unlike previous treatments, this product can be applied anytime in the growing season. The material is injected directly into the trunk, so nothing is sprayed into the environment. We are still in the experimental phase of using this product, if you would like to try it out, give us a call.
And some we want to keep out!
EMERALD ASH BORER
presence has been confirmed by the Canadian Food Inspection Agency in the City of Ottawa, Ontario. This invasive beetle does not spread quickly on its own. In fact, it is most commonly spread when people move materials which it has infested. Moving these materials even just a few kilometres away can spread the emerald ash borer to new areas.
Trees are being destroyed through the transportation of invasive insects and diseases in firewood. Click here to see a video about the Emerald Ash Borer. For Trees Company supports the Don’t Move Firewood campaign. You can rest assured that firewood sold at the For Trees Nursery was cut locally.
DUTCH ELM DISEASE
only affects elm trees. The entire population of elms in a community can easily be destroyed by Dutch Elm Disease within a decade. DED is caused by a fungus called Ophiostoma ulmi (Buis). The fungus is spread by two species of bark beetle. They breed under the bark of dead and dying elm wood, then clog the water conducting vessels of the tree, causing wilting and eventually death.
The American and Siberian elm are the most common elms grown in the Calgary region. At present, Alberta has the largest DED-free American elm stands in the world. A total of 219,334 elms, worth $634 million dollars, grow in Alberta’s urban areas. Alberta has been fortunate to remain DED free for many years however, in 1998 one elm tree in Wainwright was confirmed to have the disease. The tree was immediately removed and burned. It is believed that firewood brought into the province was the source of infection. Alberta is still DED-free.
Alberta has an elm tree pruning ban. To reduce the risk of DED, pruning of elm trees is prohibited throughout Alberta from April 1 to September 30 each year. Fresh cuts from pruning attract the beetles that can spread the disease and increase the chance of an infection. This ban period is intended to coincide with the period during which elm bark beetles are most active. For Trees arborists prune dead and dying elm branches from October 1 to March 31. This helps to reduce beetle breeding habitat.