SPRUCE TREE FUNGUS

COLORADO BLUE OR COLORADO GREEN SPRUCE TREES ALERT!

Many of you have Spruce trees on your properties. Most of our clients already have us treating their Spruce trees for the destructive Spruce Mites but now there is an additional concern. If you have one or more Spruce please read on to better understand what is going on with these trees.

For those of you who might be unsure which type of tree we are referring to, below is a photo of a healthy Spruce.  If you haven’t paid much attention to area Spruce trees, we request that you do going forward. As you drive around different neighborhoods and up and down main thoroughfares, you will notice Spruce trees in different stages of distress. While Spruce Mites were the biggest enemy of Spruce during the last several years, these trees are now additionally being attacked by a fungus known as Rhizosphaera Needle Cast. Below are photos of Spruce under attack by ‘Rhizosphaera’.

What Brought This On?

There were negative effects created to tree root systems during the wet years of 2009, 2010 and 2011, two of which were the wettest on record. When the ground is wet for abnormally long periods of time, oxygen has trouble penetrating the wet ground and some of the roots suffocate causing different degrees of what’s referred to as ‘root rot’. Then in 2012 we had the worst drought in history. The four connected years of 2009 to 2012 were horrible years for trees and they are still paying the price today.

When those years occurred, the Department of Agriculture and the Morton Arboretum announced that many trees could die over the next 10 to 12 years due to the root damage sustained during that period of time due to the stressful conditions that existed back then. That means trees are potentially at risk until 2024.

Although root damage can put any tree at risk, trees such as Spruce have been most adversely affected by those years. When a tree is under stress, it is more prone to attack by insects, Mites and fungal disease.

So what’s going on now?

A couple years ago we started seeing minor Spruce tree damage from Rhizosphaera ‘Rhizo’ Needle Cast. We had first seen Rhizo about 40 years ago. Then we noticed it again about 28 years ago and then again 15 years ago and each time it was minimal and seemed to disappear before any substantial damage occurred to these trees. We hoped it would remain a minor annoyance and that it would not be much of an issue as it had in the past. We have to report that last year, and it appears this year, Rhizo has been accelerating, much worse than ever before. It is so widespread, and in so many areas, that we are guessing it’s not going to go away any time soon, if at all. As you saw in the photos this is a devastating disease which does severe damage and can, and has been, killing Spruce trees.

Under current conditions, we are forced to suggest a change to our treatment program for any Spruce trees important to your property.

We are suggesting two fungicide spray applications for Rhizosphaera in the late Spring and early Summer period about 3 to 4 weeks apart followed by a third application late Summer into Fall consisting of a fungicide/miticide mixture. We feel this will give the best protection from both Rhizo and Mites.

Most importantly folks, even if you have Spruce trees which appear to be ‘perfect specimens,’ and you were not spraying for Spruce Mites, you should really consider the recommended program to protect them. Since this fungus moves as an airborne spore traveling by wind or even on the feet of birds, and then spreads within the tree itself, it is important to be proactive, not reactive.

Full Disclosure

We have never treated for Rhizosphaera Needle Cast in the past. There are high quality products available but we have no track record with their use against Rhizo. We will say however that we do use some of these products on other fungal issues and they work tremendously well so we are ‘expecting’ them to work on Rhizo. Ordinarily we test products against insects or diseases for two to three years before we offer them to clients but the way the Rhizo has progressed we feel we need to offer this option ‘untested’. We hope to have some idea of how well they seem to be working by next year and a better idea two years from now.

Why two years? Because once the fungus infects a Spruce, it takes 12 to 15 months for the damage to start showing up on the tree. Therefore, if we start treating this year for you we will only be protecting branches not yet affected because fungicides work on a prevention basis, never an eradication basis once it is already present.

If you aren’t sure you want to protect against the Rhizo fungus we recommend at least sticking with your current Mite spray program as the Mites are everywhere and very damaging in their own rite.

Japanese Beetles

Destructive Japanese Beetles will begin emerging from the ground sometime between late June and early July. The timing changes every year. With Spring off to such a late start this year, they could even emerge a bit later as most insect issues were delayed this year.

Japanese Beetles need a certain number of days of ground temperatures being maintained at a certain point before Mother Nature lets them know it’s time to emerge. They will hatch over a period of 5-8 weeks depending upon when their eggs were laid during the previous summer. The earlier a female deposited her eggs into your lawns during the summer of 2017, the earlier they will appear in 2018. Eggs laid later in the Summer will cause those particular beetles to emerge later, however most typically show up in the first 30 days once they begin emerging.

With Japanese Beetles, you can never eliminate or avoid ‘all’ of the damage they do even if you were to spray weekly. We do not advocate spraying that often as it would be too costly. Japanese Beetles emerge from the ground as full sized, ravenous eating machines. Even if someone did spray every week some damage would still occur as these insects have to do some feeding to ingest enough insecticide to kill them. We recommend 2 to 3 spray applications to ‘limit’ or ‘manage’ the lion’s share of their damage.  Read more about Japanese Beetles…

This is a Linden tree 100% defoliated by Japanese Beetles. This is the type of severe damage 2-3 spray applications will avoid.

And these are the cute little critters who caused all that damage. Japanese Beetles attack a variety of trees and shrubs. Be on the lookout.

Summer Aphids…

A few years ago we started receiving calls from clients who had Linden trees dripping copious amounts of sap. Along with that messy, sticky sap came hundreds of bees and wasps feeding from it. Sap was all over anything under or near these trees. Since the Linden is also the Japanese Beetle’s favorite target as well as the Summer Aphids, these trees could really be under attack and weakened by these two different insects. If you notice sap drippage along with the bees and wasps, you might want to let us know before it gets too bad. We can spray to accommodate both types of insects as they require a special mixture of two different types of products.

Remember trees don’t just decide to drip sap. If sap is dripping it is definitely caused by some type of insect. Some are easy to control and some are more difficult.  Let us know if you’re having an issue!

Frogeye Fungus

As always we would like to keep you apprised of area insect and fungal issues. It was a long, cool, damp Spring and the wettest May in history. Those are prime conditions for tree ‘issues’ to flourish. There are all types of fungus, leaf blight and winter damage occurring right now, causing leaves to blemish, yellow and fall from a wide array of trees and shrubs. Also some green leaves will start falling soon.

Green Leaves Falling

We mention this almost every year. A fungal issue called Anthracnose causes stems on leaves to weaken and then fall. This can be pretty heavy at times. Its favorite targets seem to be Ash and Hickories but can affect other trees as well. Don’t worry about this. It doesn’t really hurt the tree and it’s not really controllable.

Yellow Leaves Falling

Yesterday we received a call from close friends who are also Apple Scab clients. They told us they were seeing bright yellow leaves falling from the same Crab that we treat for Apple Scab and they thought the leaf fall was due to that. We knew there was no way it could be Apple Scab. Considering how late this spray season started due to the long cold drawn out Spring, it is positively too early to be Apple Scab.

Here are a few photos of what we found once we arrived.

frogeye fungus  frogeye fungus

 

 

 

 

 

 

This yellowing leaf drop is due to ‘Frogeye Fungus‘, which is different from Apple Scab. We have never treated for Frogeye in the past as its presence has been very sporadic over the years. The products we use for Apple Scab obviously won’t prevent Frogeye or this tree wouldn’t have contracted this fungus. It is important to note that Frogeye isn’t as debilitating to Crabs as Apple Scab.

There are over 100 different varieties of Crab Apple trees and only a few are susceptible to Frogeye. In the past, leaf drop due to Frogeye has occurred over a period of a few weeks. The tree thins out a bit but re-foliates as the Summer progresses, whereas with Apple Scab, the tree defoliates, often almost completely, and stays that way from July through October. If your Crab Apple is exhibiting these symptoms we understand that it’s frustrating treating for one fungus and then have a different fungus come up unexpectedly. There are no fungicidal products that treat every conceivable fungus that might occur.

Sometimes, as is the case here, there is no way to predict certain issues until they happen. We don’t offer treatments for ‘what-if’s’. We offer treatments for what we ‘know’ will be a yearly issue. It makes no sense to treat year after year for something you might only experience once in 5 or 10 years.

There are many environmental factors that affect trees. We can treat and protect trees from the most serious issues, but you can’t treat for everything, nor should you.

With valuable trees, you control serious issues and root feed them to keep them as healthy as possible which more often than not keeps them strong enough to fight off a lot of what Mother Nature throws at them. Any concerns or questions feel free to give us a call.