Trapping Laries

That's Laricobius beetles for the uninitiated. And yes, this is a Fraser fir blog, but every once in awhile I like to put something in about other conifer pests like hemlock woolly adelgid (HWA).

One of the predators being released for HWA is Laricobius nigrinus. Last week I went out with Jim Hamilton, Watauga County Director, and Bill Sweeney with the Bent Creek Experiment Station, to learn how to trap for these beetles.

Sweeney is looking at the traps every week to see if any Lari beetles are coming up out of the ground to feed on HWA. These beetles pupate in the duff under the trees. This first trap is a bucket placed over the ground with bait at the top (infested hemlock branches) where the beetles, if they were present, would congregate.

Each week he puts in fresh shoots in the container at the top. When the week-old shoots are removed from the trap, the foliage is beaten over a sheet to look for beetles. This photo shows Bill and Jim looking for beetles.

A second trap is placed around the hemlock trunk so that any beetles moving up the tree will be captured.

Unfortunately, we didn't find any Laricobius last Wednesday when we looked in Valle Crucis. I don't know if Bill found any at his other locations.

These beetles were released at Hemlock Hill behind Lees-McRae College in Banner Elk. Jerry Moody, the County Extension Director in Avery County, and I looked at these hemlocks on Friday. It had been a long time since I had been there.

Sadly, most of these huge trees have died. Here Jerry stands beside a dead giant. We also took some beats from younger hemlocks that are still alive, but we didn't find any Lari beetles.

HWA is having a sad impact on our forest hemlocks. Each time we have droughty conditions, it seems like more hemlocks die.

On a brighter note, Jerry and I visited a site where we had treated hemlocks with a trunk spray of either Safari or Merit + Pentrabark. The Safari treated trees at the low rate of 12 oz/gallon had only dead adelgids. We only took a quick sample of Friday, but the results were very encouraging. We'll make additional observations this spring.

Movento Gets Relabeled

According to an October 18, 2010 press release from Bayer CropScience, Movento insecticide has received EPA registration for a second time. The original registration of Movento was cancelled because of administrative errors committed by EPA during its initial review and approval of the active ingredient, spirotetramat, in 2008.

I have been working with this systemic material for the control of many pests of Fraser fir including balsam twig aphid, balsam woolly adelgid, elongate hemlock scale, and mites. I have been interested in Movento because it is systemic, has the potential to control a wide variety of pests, and is less toxic than many pesticides used on Christmas trees.

When I work with new products, I like to conduct my own spray trials where I can closely determine initial pest levels and really see how well the product is working. But I also like to get the product into the hands of growers to see how well it works in real farm situations. With the issues with the labeling of Movento, I haven't been able to work as much with the product as I would have liked. This ruling by EPA clears the way for more complete evaluations.

Updates on Website

As seen from some recent letters to the editors of the High Country Press, the public continues to be concerned about the production of Christmas trees in the area. Also, as we get nearer to Christmas, the media including blogs and other social media question the environmental safety of real Christmas trees. Because of this, I have revised the information on the web site, "Frequently Asked Questions about Christmas Trees and the Environment." This web site is found at: http://www.ces.ncsu.edu/fletcher/programs/xmas/environment/index.html

The updated information reflects new pest control practices, updated cancer rates for mountain counties, and newly available links. The site can be used as an overview for concerned citizens or references for reporters.

If you have any questions, comments, see any errors or have additional information that should be added, let me know.

Time for Annual Bashing of Christmas Trees

It's October -- time for Halloween, Christmas decorations to pop up in stores, and the annual bashing of real Christmas trees. Thought I'd share the following that I sent in to a blog connected with artificial trees praising them as the environmental choice.

"...there is no reason why the joy associated with the Christmas evergreen may not be a means of arousing in the minds of children an appreciation of the beauty and usefulness of trees; and keen appreciation of the beauty and usefulness of trees is a long step toward the will to plant and care for them (Arthur Sowder, US Forest Service, 1949)."

A Christmas tree is a celebration of life -- renewed life in the dead of winter -- renewed life because of the birth of a Savior. How can that be celebrated with a big plastic brush? Because that's all an artificial tree is no matter how lifelike. It's not a tree. It never provided a perch for a butterfly or protection for a bird from a summer storm. It was never brushed by a deer or bear as they walked by. It never felt the pull of the sun to make it break bud and grow. It was never alive as a real tree was.

So what if you cut it down? Another will be planted in its place. That's the circle of life, after all. If people really wanted to be environmentally conscious at Christmas there would be no lights, no presents, no feasts, no visits to family. Cutting down one tree at Christmas is nothing compared to the trees cut down to supply an average home's paper needs for the year. But a real tree becomes part of the family if only for a few weeks. And after the season is over, it can be recycled into mulch to provide protection to new plants in the spring.

Don't we have enough plastic from China already in our lives? Shouldn't a really great Christmas have a real tree?

So yes, Virginia. It's OK to use a real tree to wait for Santa on Christmas Eve. It will make the Jolly Old Elf smile to himself to think that not all the traditions of yesteryear have not been forgotten.

A Word About Spray Suits

Lots of folks wear the basic disposable Tyvek coveralls when applying pesticides. These state that they are not water proof, yet lots of folks use them when applying not just dry pesticide formulations, but wet formulations and even high pressure sprayers.

On Friday, Jerry Moody and I applied some materials for fall control of algae. We don't think they will work, but we wanted to be sure. One thing that some growers are doing is spraying bleach on trees to clean them up. We tried that last year, but with a backpack mistblower. This year we tried it with a high pressure sprayer to see if that will work any better since it didn't work at all last year. I sprayed a 3% solution of bleach on about 30 large trees with a high pressure sprayer, doing a thorough job of coverage. I wore a white tyvek suit.

Well, look at my shirt at the end of the job. My purple shirt was bleached where the zipper on the Tyvek suit was. If it had been a pesticide, I would not have been protected from it.

Take home message? When spraying with a high pressure sprayer, you need something water proof.

We'll let you know in a couple of weeks what kind of algae control we got.

(And I liked that shirt too!)

Cryptomeria Scale Found in Ashe County

A small field of trees in West Jefferson has what I think is Cryptomeria scale. I had samples sent to the Plant Disease and Insect Clinic in Raleigh to confirm it, but it definitely looks like the same thing we saw in Macon County earlier this summer.

There are several differences between Cryptomeria scale and elongate hemlock scale. First of all, there are more symptoms of yellow blotches on the needles. Most of the trees with Cryptomeria scale have these symptoms, whereas most trees with EHS have no yellow discoloration.

A close-up of the foliage shows the striking symptoms. Note how it is worse at the lower part of the shoot where more scales have settled.

The scales look quite different from EHS. The newest growth appears to have mostly nymphs or younger scales. They look almost like yellow dimples on the needles. They also reminded me of eggs cooked sunny side up with really big yolks!

Under the microscope you can see that even the young scales hide themselves under the cuticle on the needle, giving them protection, and making them harder to see. I guess that's what gives the appearance of a big yolk with a bit a white around it when seen through a hand lens. There are also some more mature scales in this shot at the top. They look bigger of course.

On the older growth, the scales seem to grow on top of each other. There are more mature scales. They look sort of round, and many look brownish, but those, I think have already died. The healthy scales are yellow when you look at them under the microscope.

Many of these scales have been fed on by the twice stabbed lady beetles. These were everywhere on the trees, just like they were in Macon County. They left holes in the scales.

The adult lady beetles feed on the scales as well as the larvae.

Here are some lady beetle larvae. There are so many larvae, they almost look like they are feeding on and damaging the trees. But they are feeding on the scales. However, there are so many scales, they don't destroy them all. I looked at some needles under the microscope where the lady beetles had obviously been feeding, and there were live scales with eggs still underneath dead scales which had been fed on.

Here are two adults with eggs and some crawlers. It was hard to get a good picture of the crawlers as they were moving around a lot. But basically, crawlers all look about alike.

A scale that hasn't yet produced eggs was flipped over for this photo. The thin coppery line going from the middle of the scale is the feeding tube. You can see it best against the green of the needle at the top and middle of the scale.









These trees really went down hill over the last month. The grower didn't notice anything wrong with his trees until recently. In fact they thought that it was worse today than it was just last week. And in reports from other states indicate that the scale builds up and spreads very quickly. Its also been very dry in Jefferson this summer which I'm sure helped the symptoms be worse.

These trees are in a residential area with houses all around. As with the other site in Macon County, the best explanation as to why Cryptomeria scale showed up is because someone purchased nursery plants from up north where this scale is much more common, and they moved into the Frasers. Cryptomeria scale feeds on many types of conifers, but it certainly seems to like Fraser fir.

The grower is going to spray these trees within a week with Dimethoate, Asana and Safari. Before spraying, they will cut out and destroy the worst trees. In fact, it would take at least a couple of years of good growth to cover up heavily damaged. trees. I thought it best to add the Safari on an experimental basis as research from other states indicates that Safari works well.

It's getting a bit late in the season to control these scales, but hopefully they will get some control. I'll assess them after a month to see how well the treatment worked and probably again in the spring. If need be, the grower plans to treat again in the spring.

Are there more sites with Cryptomeria scale in western North Carolina? It is certainly possible. Most growers now know what EHS looks like, but they could easily mistake this scale for EHS. It does look different, however. It is more rounded that elongated. There are also no white males, and no white waxy discoloration on the top of the needles. Another tell-tale sign are all the twice stabbed lady beetles which appear to be very characteristic of this scale.

This scale is much worse than EHS. It appears that it spreads faster, and it definitely has a greater effect on the tree. We have yet to see if it is just as hard or even harder to control. According to reports from Pennsylvania and Connecticut, control of both scales is similar.

If anyone thinks they have Cryptomeria scale, please let me know and I'll come out and look at it. Everyone needs to keep an eye out for this pest, so we can track if it is spreading.

Algae Control Results

Several people have been concerned about algae again this year. However, I don't think the algae has been as bad this year as last year. In the two fields where we treated, there was definitely more of it on the 2008 growth than the 2009. We had a hot, dry spell in the summer that no doubt reduced the development of algae, but there are still problems. (Photo was taken by Bryan Davis last year showing extreme discoloration in 2009. Note that the current year's needles are not affected).

The first thing to realize when looking at algae control is that the best you can do is prevent more algae from developing. It's hard to cure algae once it's already there. It develops primarily on last year's foliage -- not this year's. It appears that it comes in the June time-frame. Therefore in these spray trials, we were looking at algae development on last year's growth -- that is 2009 growth. For the most part, we didn't do anything to reduce discoloration on 2008 growth (which developed the summer of 2009) or earlier. Still, if you can go to market with 2 years of good green color, it should be good enough.

This photo was taken under a microscope showing some algae on the needles. It is easy to see with a hand lens. It is also easy to wipe off the surface of the needle.

We applied different materials for algae control this spring before bud break at 2 sites -- one in Mitchell and one in Avery. Thanks to Jeff Vance and Jerry Moody for help in finding locations to work in and spraying the materials.

All applications were made with a backpack mistblower. At both sites, an untreated row was left between each treated row to reduce cross contamination of treatments.

At the Mitchell County site, treatments were made on rows of 10 trees. There were 3 replications. Applications were made on April 29 using one of the following materials:

1. Kocide 3000 at 3.5 pound per acre. This is a copper based material which is made up of 30% copper. Kocide label.
2. Dithane at 1.5 pounds per acre. The active ingredient of Dithane is mancozeb. Some Jackson county growers were seeing some control of algae in the fall when this material was applied. However last year, I didn't see very good results from this. Review of last year's work.
3. Daconil at 3 pints per acre. The active ingredient of daconil is chlorothalonil.

In Avery County we didn't replicate, but instead treated a long row with 30 or more trees. Original treatments were made on May 5 using either Kocide, Dithane or Daconil at the treatment rates described above. Addition treatments were as follows:

1. Cosan, an organic disinfectant, at 2 teaspoons per gallon
2. SA-20 disinfectant at 2 teaspoons per gallon. This product is made of 10% dimethyl benzylammonium chloride and 10% dimethyl ethybenzyl ammonium chloride. It is used to disinfect pots, greenhouse areas and tools.
3. Kocide applied twice -- on May 5 and again on May 19
4. Kocide applied once on May 19

Jerry, Doug Hundley and I looked at the Avery County treatments yesterday, and Jeff Vance and I looked at the Mitchell County treatments this morning.

There appeared to be more algae developed at the Avery than the Mitchell County site. This surprised me as the Mitchell County site was much worse last year. (This photo, taken in Mitchell County, shows a shoot from an untreated tree with algae on last year's growth).

All treatments appeared to have some effect on the algae. The Dithane and Daconil didn't work as well as the other products. Kocide appeared to work best. Applying it twice seemed to work a bit better, and applying it later in May also seemed to work some better.

This photo is of a shoot from a treated tree. Note that there is no discoloration on 2010 or 2009 growth. If the treatment hadn't worked, you would see discoloration on 2009 growth. The material didn't reduce the discoloration already present on 2008 growth. 

This is typical of any fungicide. They prevent disease from developing. They don't cure disease. Therefore a successful treatment will keep algae from developing the year it is applied. But that's similar to all of our pests. When you treat for twig aphids or spider mites, you don't do away with the damage you already have. Instead you cover it up with new, undamaged foliage.

I would like to repeat this next year, applying materials with either a high pressure sprayer or backpack mistblower. I suspect that the high pressure sprayer will give better control, but that most growers will prefer the speed of the mistblower. I also hope to try out some Kocide this fall to see if it will help "cure" some of the algae. I don't think it will, but since I didn't try it last year, I want to make sure. 

Take home message: It looks as if Kocide and perhaps some other materials will reduce and in some instances prevent algae from developing when applied in the spring. In fields where algae development is expected because of woods or the trees are growing close together, a preventative treatment is required starting the year before sale and continuing until all the trees are harvested.

A big thanks goes to Kelly Ivors and Gary Chastagner for their help in identifying possible treatment windows and materials.