When it comes to the well-being of the majestic spruce, the war against disease is a never-ending fight. Two enemies who are always on the radar are those pesky spider mites and needle cast diseases. Half of winning the battle is knowing what you are up against. Read on and discover what issues these threats can cause and how they can be stopped.
Needle Cast Diseases
Two primary needle cast diseases are affecting our spruce trees – Rhizosphaera and Stigmina varieties. These diseases mainly affect Colorado blue and Black Hills spruce varieties.
Symptoms
The symptoms of both forms of the disease are similar, with common results being brownish-purple discoloration and the death of older needles. Though it would be hard to detect with the naked eye, needle cast issues also cause black fungal dots to displace the standard white dots that line the underside of the trees needles.
Treatment
After proper diagnosis, needle cast diseases can be reduced or beat using two properly timed biannual applications of fungicides containing a healthy dose of chlorothalonil. The timing is crucial, as applying fungicide too early or too late in the season can mean missing the particular period of time where the tree can be best protected from the disease.
Spider Mites
These cool-season mites are most often found during the early part of the growing season. They are true pests, but proper treatment can save your trees from them without much hassle.
Symptoms
Like needle cast, spider mites infestations often affect the regular white dots of the spruce tree, often causing them to turn yellow. They cause widespread harm to the trees as they feed, and often can be easily seen by shaking an affected branch over a white sheet of paper and watching the black mites fall.
Treatment
Treatment for spider mites can actually be an easy process if you stop the issue before they cause too much damage. Often, even a forceful jet of water to the infested area can wash these pests away. Insecticidal soaps and culture control are also helpful tools in the fight against these irritating mites.
Needle cast disease and spider mites are just a couple of the potential threats to the forests of Michigan and the greater Midwest area, but proper care and attention can help quell these risks.
If you are looking to fill in your landscape with the finest bare root trees or shrubs – including beautiful spruce trees – then look no further than the vast inventory offered by Cold Stream Farm. Our wide selection makes us Michigan’s finest wholesale and retail nursery, backed by nearly 40 years in the business. To learn more or to place an order, call us today at 231-464-5809.
