Hemlocks And Alberta Spruces Trees & Common Diseases

Hemlocks and alberta spruces trees & common diseases. Spider mites and Woolly Hemlock Adelgid crawlers are the main causes of death among Alberta Spruces and hemlocks in the wild.

Both Alberta Spruces and hemlocks are popular trees in East Coast gardens. These stately trees are frequently cultivated for privacy, reaching heights of twenty to forty feet over a twenty-year period. Unfortunately in less than one season both can be severely damaged, if not totally destroyed, by disease. Alberta Spruces are particularly susceptible to spider mites, while hemlocks are devoured by an insect called Woolly Hemlock Adelgid. If not properly identified and treated, both trees will quickly lose their leaves and die.

The first sign of spider mites in Alberta Spruces is the browning of the leaves. Patches of brown foliage can literally appear overnight on otherwise healthy trees. To ensure that the trees are not suffering from other problems such as poor soil or over watering, shake a limb over a white piece of paper. If the tree is infected with mites, the paper will be peppered with small black flakes. If adding a little pressure to the flakes with your thumb produces reddish-brown streaks across the paper, you most definitely have mites. For best results, you should check for mites even if there are no other signs of disease. Once the brown foliage has appeared, the mites are already in an egg stage that makes them more difficult to eradicate.

Hemlocks are favorite hosts of insects called Woolly Hemlock Adelgid crawlers. These crawlers are minute sucking insects whose eggs form a powdery mildew around the base of the hemlock's needles. The most popular feeding time for these damaging insects occurs around June, although the woolly egg tufts are visible year round. Due to hemlocks' dense foliage, most gardeners do not spot the creeping mildew before it has attacked the entire tree. Early warning signs of a hemlock infested with Woolly Hemlocks Adelgid crawlers are stunted growth and discolored needles. More advanced stages of infestation result in limb loss starting with the trees' uppermost branches.



The best method for preventing destruction of your spruces and hemlocks by these insects is early detection and constant attention. Many gardeners prefer the high-pressure steam bath for their Alberta Spruces. Using a high-pressure hose, mites are dislodged from the spruces, but so will everything else if you are not careful. The next most popular savior for both spruces and hemlocks is insecticide soaps. These soaps are available at any gardening store and are typically easy to use. Horticultural oil is just as popular and effective. Both soaps and oil suffocate the insects, but are gentle on the rest of the ecosystem living in your trees. For particularly bad infestations of mites or crawlers, gardeners can use Talsar (pyrethroid) or Hexygon (miticide/ovicide). Instructions should be followed exactly as misuse could ruin the trees quicker than the insects.

Hemlocks' height and dense foliage make home care difficult. Some of the worst infestation may be in the tree's top canopy, far out of reach for the average gardener. Furthermore, the hemlock's dense foliage prevents penetration of soaps and oils usually applied with standard garden hoses. There is no natural control for Woolly crawlers, and you might need to rely on a professional gardener who will have access to the proper equipment and commercial-use chemicals, like imadicloprid. Canadian and Eastern Hemlocks (tsunga canadensis) have very little resistance to crawlers and die quickly. Cardinia Hemlocks (tsuga cardinia) are somewhat more resistant, but the Japanese Hemlocks (tsuga diversifolia) show the most resistance in succumbing to the affects of Woolly crawlers.

Spider mites and Woolly Hemlock Adelgid crawlers are the main causes of death among Alberta Spruces and hemlocks in the wild. For gardeners, infestations of these insects are so damaging that they can easily lose their twenty-year old trees in a matter of weeks. Knowing the danger signs of infestation, however, can ensure your hemlocks and Alberta spruces continue growing strong for another twenty.

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