They don't really have any answers. There are multiple trees ranging from 6ft to 20ft. If you are not familiar with sneed, im assuming you have no awnsers for me.
If your trees have all three issues I'd honestly not invest in treatment or maybe eradicate the worst specimens.
Both SNEED and spider mites are caused by stressed trees. Perhaps by the drought two years ago and now this horrendous winter which MN was slammed with.
If you decide to treat the trees there is a treatment that seems to work for both SNEED and Rhizo per the link below.
Spidermites are just along for the ride on these already stressed trees. They are usually easy to treat...as simple as a strong blast of water.
I'm not sure how I feel about this diagnosis. I find it hard to believe that all your trees had all 3 conditions. SNEED and Rhizosphaera needle cast can both be treated the same way You can use any fungicidal spray that contains chlorothalonil, such as Daconil.
The timing of the application is critical and has probably already passed for you this year. It needs to be sprayed when new growth is 1/2 way elongated, then again in 3-4 weeks. In z6 I just finished my second application, so I assume in z5 you have already past the first spray period.
In addition to chemical treatment, you need to evaluate the location of your trees. Is it appropriate? Do they get enough sun? Is your sprinkler system soaking the trees? Shade and moisture are the 2 things that really allow fungus to thrive. Also, Air flow. make sure their is sufficient movement of air around the plant.
I have no experience with mites. Do you know how they diagnosed this? I think you should be able to shake a branch over a piece of white paper and actually see the mites with the naked eye.
First treatment of chlorothalonil has been applied. There is an overhead sprinkler system used when needed. Sprinkler system runs once or twice a week at night, but only when needed. There is good airflow through most areas.
You are correct on the spider mite identification. Red streaks are bad, black are ok. Wen have been treating with floramite sc.
The overhead sprinkler could be causing a lot of your issues. Are the needles getting wet from this system? You want to water at the base of the tree, preferably using a drip system of sorts. Needle moisture is the biggest problem I see so far. Watering at night is a very bad idea as well. In lawn care it is highly frowned upon because the water doesn't have a chance to dry off the surface of the grass quickly without the sun, moisture sits there all night, which again, encourages fungus. The same is true for trees.
How are you checking moisture. How fast does you soil drain? I'm assuming slow, since it is clay. You will need to be especially careful with your watering program in clay soil. Spruces do not like wet feed, they like a quick drink and then near drying. Insert your finger to first knuckle to check for moisture. If dry water, if not, leave it alone.
Dig a whole 1ft by 1ft. Fill it with water, let it drain. Then refill the hole and time how long it takes to drain. This will give you a visual understand of how long the water is sitting at the root level.
How much Sun are the trees getting?
This post was edited by SC77 on Thu, Jun 12, 14 at 14:11
We had a large pine start turning brown. My sister took a snipping of pine to her college agricultural lab where they diagnosed it with spider mites, observed under microscope. They recommended a spray (I don't remember what it was) and they told us to spray the tree regularly with the hose, as it would help wash away the spider mites. We treated the tree and regularly hosed it down and the tree recovered fully. It has been over 30 yrs and the tree is still there; never again did it contract a disease either.
OP, yes SNEED indeed! I wish I didn't know what that was, but I do. To be blunt, the species you're trying to save are magnets for this complex of problems. And as unpalatable as it may be, I'd get rid of the Black Hills-always my least favorite spruce, even before SNEED, and plant some Norway spruce and maybe just our regular Western Great Lakes native version of white spruce. Why, oh why did we have to plant a tree whose genetics are adapted to an area with very dry air, here in an area where the air is rarely that dry, at least during the growing season? In case it's not obvious,I really hate everything abut BH spruce!
All that rant notwithstanding, the Daconil is a good option for fungicide, as is good old Bordeaux mixture. I've seen the latter work well on Colorado spruce that had bad cases of Rhizosphaera. Just another one to consider. But I'd plant some new, more well-adpated trees.
ken_adrian Adrian MI cold Z5
MinnesotatroubleOriginal Author
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MinnesotatroubleOriginal Author
whaas_5a
MinnesotatroubleOriginal Author
sc77 (6b MA)
MinnesotatroubleOriginal Author
sc77 (6b MA)
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