Watch your conifers!!

There are several problems that can affect the trees in our municipality and surrounding region. The most important problems are those affecting certain species of conifers, including cedars, white pines, and spruce. Unfortunately, climactic conditions contribute; reduced snow coverage, mild temperatures, frequent freezes and thaws. Here are some tips to battle, and even prevent, some of the problems you might come across.

We have identified several cedar hedges infested with Arborvitae Leafminer The Leafminer is an insect that feeds on the interior of twigs and branches of cedars during their caterpillar stage, which causes them to wither and turn brown.  Most cedars survive, but they could die from repeated annual infestations.

Leafminers feed on leaves, which causes them to turn yellow, then brown. They start on the outer branches and work their way towards the trunk. Most infested trees recover. Trees can lose up to 80% of their foliage and survive.

Well-tended cedars: those that are watered, fertilized with a mature compost, sheep manure, or 100% natural fertilizer specifically for cedars, mulched and pruned, are better able to withstand Leafminer infestations.. You can also protect your cedars along the road by wrapping them with a tarp, especially if salt is used to melt the snow.

There is no need to control Leafminers if a tree is not heavily infested, or if it has not suffered repeated infestations over several years, or if it has not known drought or periods of dryness. Natural pest control results in the reduction of the Leafminer population.

You can minimize the damage caused by Leafminer infestations by destroying the caterpillars in the spring. Check your trees in March, April, and in May. Cut off the tips of infested branches and burn the clippings.  You can also wait until the eggs are laid, prune the branches with the eggs, and burn the clippings.

To control a serious infestation with a low impact insecticide, in June and July spray a solution of Safer brand “End All” or a mixture of  60% Safer brand “Trounce”, and 2% vegetable oil and 38% alcohol.  These two products can be used according to the bylaws on pesticides in effect in Notre-Dame-de-l'Île-Perrot.  The application must be made when the adults emerge during the egg laying period.  This will effectively control the population of nocturnal moths, and consequently reduce the population of Leafminers in subsequent years. The treatment must be applied at the right time to be effective, and should be repeated 7-10 days later. If it rains within 24 hours following the application, it is recommended to repeat the treatment. Once the eggs hatch and the larvae start to feed, it is nearly impossible to regain control with low impact pesticides. Insecticides should be sprayed only by qualified and authorized personnel. Always read and respect the manufacturer’s instructions on the label.

Drought and Pines and Firs

Fir trees (abies) and white pine trees (pinus) were particularly affected by the dry winter of 2001. The most frequent symptom of dryness is the discoloration of needles, turning from brown to red, starting at the tips or the branches, or covering the entire tree. In the latter case, it is impossible to save the tree.

What can you do to prevent this from happening again next winter?  It is difficult to predict what the weather conditions will be next winter.  It is better to ensure that you are giving your trees the best possible chance by providing them with sufficient water and nutrients to pass the winter without damage.  If your soil is sandy, water your trees deeply in the fall and make sure that your soil will hold the water by adding peat moss and compost.  Claylike soil hold water better.  If the fall is dry, you will need to compensate by bringing more water to the soil, by adding organic matter like that previously described.