Spruce spider mites can be a major problem for spruce trees, but with proper monitoring and treatment, the damage can be minimized.  It is important to be aware of the signs of spruce spider mite infestation and to take steps to prevent and treat the problem.

Mites can be especially problematic in areas that experience high plant stresses, such as constant wind and frequent drought.  As such, spruce rows on farms and acreages are often more seriously infested than trees in residential urban yards.  Spider mites are common throughout Alberta.

The first sign of spruce spider mite infestation is the presence of fine webbing on the needles of the tree. As the infestation progresses, the needles will turn yellow or brown and may drop off prematurely. Another sign of infestation is the presence of the spider mites themselves, which are tiny, reddish-brown or greenish-white creatures that can be difficult to spot without a magnifying glass.

It is often useful to use miticide sprays to kill the spider mites in situations where beneficial predatory insects are not sufficient to keep the spider mites in check.  We use products that are registered for the control of mites, and rotate them from year to year to avoid developing pesticide resistance.  We also use products that are safe for the trees.

Another important step in preventing spruce spider mite infestations is to maintain the overall health of the tree. This includes providing the tree with adequate water, fertilizing as needed, and pruning away any dead or diseased branches. A healthy tree will be less susceptible to infestation and will be better able to recover from any damage caused by the spider mites.  We often see more serious infestations in situations where multiple spruce rows were planted too close together, and the competition between the maturing trees causes serious competition for available water and nutrients.

It is important to be proactive in preventing and treating spruce spider mite infestations in spruce trees. By monitoring for the presence of webbing, yellowing or brown needles, and spider mites themselves, removing infested branches and needles, using miticides, and maintaining the overall health of the tree, you can help to protect these valuable trees from the effects of spruce spider mite infestation.