Dutch Elm Disease


Dutch elm disease cause leaves to wilt	Leaves then brown and die

Dutch elm disease (DED) is the most devastating shade tree disease in North America. It is a wilt disease with an extremely high fatality rate among elms.

How Dutch Elm Disease Kills

Dutch elm disease (or DED) is caused by a fungus. After the disease is contracted, spores rapidly reproduce and spread toxins throughout the tree.

The fungus Ophiostoma (Ceratocystis) ulmi attacks various species of elm. It can kill a tree within a few weeks or it can kill it gradually over a period of years. The fungus blocks the water-conducting or vascular system of the tree preventing water and minerals from reaching the branches and leaves. The leaves wilt and eventually the tree dies.

There are two strains of the fungus in North America - the non-aggressive strain (O. ulmi) and the aggressive strain (O. novo-ulmi). While the elm’s natural defense mechanism tries to fight off the fungus, the aggressive strain often moves too quickly for the tree to react without human intervention.

A younger fast-growing tree can die quickly, but some younger trees seem to have a degree of natural resistance to DED. However, this resistance tends to wear off after 15-20 years. Slow-growing older trees can linger for a year or two.

Symptoms

Brown streaking of wood as a result of Dutch elm disease infection.

Discolouration of the wood is also a sign of the disease. If you peel back the bark on a wilted branch, you will see some streaking on the wood.

An infected elm tree usually exhibits symptoms soon after infection. Because of the speed with which the disease attacks, detecting symptoms as early as possible is essential for treatment. The first sign of the disease is the sudden wilting of leaves in the upper reaches of the tree. Next, the leaves change colour from green to yellow to brown. They then shrivel and die.

If the infection occurs very late in the season, the leaves will appear to fall normally. However, the following spring the new leaves will be smaller than normal. The tree will often die before mid-summer. In late summer, it may be difficult to distinguish between wilting and natural fall colours.

Control

Control efforts have focused on two areas - prevention and treatment. The spread of Dutch elm disease can be effectively checked with a stringent sanitation program involving surveillance, timely pruning and proper disposal of infected wood. Directly attacking the elm bark beetle population is less effective and often not necessary - only a very small percentage of the beetle are carriers of the disease.

Preparing your elm by improving the soil with mycorrhizal fungi and fertilizer can also boost a tree's strength. Click here for more.

Treatments have so far been based almost entirely on fungicidal injections. There are indications that new treatments resulting from advanced molecular biology research will become available in the future.

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TreeHelp Annual Care Kit

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Description

TreeHelp developed easy-to-use Annual Care Kits to help homeowners maintain healthy and vibrant trees.

TreeHelp Annual Care Kits provide health supplements that are specific and appropriate to the type of tree that you care for. The supplements are designed to promote root-development which will have a lasting effect on the long-term health of your trees. Root development is vital for a tree because it gives the tree a reserve of strength and vitality that will help it survive through periods of drought, nutrient deficiency, insect infestation or disease. Too many fertilizers and other soil additives on the market focus on immediate impact - like "candy for trees". Our soil treatments, on the other hand, provide nutrients and organic elements that will help your tree today and for many years to come.

Some of our more popular kits include:

Palm
Contains 5 Complete Fertilizer spikes with high amounts of Manganese, Magnesium and Potassium, crucial to palm tree health.

Citrus
Contains specialized citrus fertilizer spikes loaded with micronutrients to improve tree health and fruit production

Birch
Birch trees are vulnerable to devastating insects such as Bronze Birch Borer. ?ÿThe Birch Kit is designed to promote stronger growth that helps make your tree less susceptible.

Customized kits are also available for over 90 other types of trees.

Having the right composition of minerals and organic material is extremely important in maintaining tree health. As a result, all of our kits are "custom-built" with specially selected components to suit a particular tree type. For example, the mycorrhizal fungi that benefits an oak tree will have no effect on a maple. And the fertilizer recommended for use on a pine would not be ideal for an elm. With our custom care kits, you can be certain you are applying the right treatments to your trees.

Step 1: Mycorrhizal Fungi

Mycorrhizal fungi is a relatively new soil treatment for trees. Co-existing with trees and plants in nature for hundreds of millions of years, these beneficial fungi provide a "safety net" for the tree in times of stress. By colonizing the roots and extending themselves further into the soil, the fungi enable the tree to take in more nutrients and moisture. The result is a healthier, more robust tree better capable of withstanding the many stressful conditions that exist in an urban environment and to better metabolize nutrients.

Because trees are often transplanted into non-native soils, and because urban soils have often been damaged by pollution and compaction, it is essential to re-introduce mycorrhizal fungi to the soil. Our custom care kits match the correct type of mycorrhizal fungi with specific types of trees.

Step 2: Fertilizer

Fertilizer will always be an important component of a comprehensive tree care program. But it must be done properly. Nutrient balances are difficult to achieve and improper fertilization can have drastically poor effects on trees. All too often, trees are fertilized with Nitrogen-rich, quick-release fertilizers. Not only does this have the potential of 'burning' the soil around the roots, it can also promote structurally weak growth that can attract insects and disease. Our fertilizers, on the other hand, slowly release a carefully measured balance of nutrients into the soil for a constant feeding that provides more long-lasting benefit to your tree.

The fertilizers that are included in our custom care kits have been specially selected to provide maximum benefit to a particular type of tree. The formulations are often very different from species to species and target different biological structures. The result will be a healthier, more vital tree.

Step 3: Biostimulant

TreeHelp Bistimulant is a dry, water-soluble green-up powder that is watered on tree roots as a root drench. BioSurge provides benefits to all types of trees, shrubs, and other garden plants. It is designed to increase the microbial activity in the soil around the root zone and encourage root and lateral bud development, improve the efficiency of a plant’s respiratory and photosynthetic systems and delay the aging process in plant tissue. The unique composition of ingredients includes beneficial bacteria, as well as humic acids extracts, soluble sea kelp, yucca plant extracts, amino acids and vitamins.