More Algae Control Results

Jerry Moody, Doug Hundley, and I rated the trees treated in Avery County for algae control today.

Treatments. The treatments are all listed on blog posting from August 27. But I'll list them again here.

1. Untreated check
2. SA-20 disinfectant @ 1 teaspoon per gallon on May 5
3. Daconil @ 3 pints per acre on May 5
4. Dithane @ 1.5 pounds per acre on May 5
5. Kocide @ 3.5 pints per acre on May 5
6. Kocide applied twice on May 5 and May 19
7. Kocide on May 19
8. 3% bleach solution on September 25
9. Kocide on September 25

All treatments were made with a backpack mistblower except for the 3% bleach solution which was applied with a high pressure sprayer.

How we did it. Taking ratings was  hard. After all, some trees don't appear to get algae at all -- whether because of their position in the landscape, their proximity to other trees, or resistance is anyone's guess. So we first looked to see if the trees had algae on older needles. The trees with algae on older needles are the only trees we counted in the data. Then we looked specifically at 2009 growth and gave it a rating of 0 to 4 where 0 = none, 1 = very light, 2 = light, 3 = moderate, and 4 = heavy. We examined 15 trees in each treatment.

Results. The results are to the right. Remember that we only counted trees that had past algae. So, the higher the pecentage of trees with no algae in 2009, the better the product was working. And obviously the lower the algae rating, the better the product worked.

The best controls were with SA-20 disinfectant and Kocide applied May 5. The Kocide applied later in May didn't work as well. Nothing worked in the fall. Again, these materials will prevent algae from developing, not cure it.

These treatments were applied to a single row and the treatments are in order going up the hill (all except for the check row which was between the Daconil and the Dithane). There was definitely more algae the farther up the hill you went, and so that may be why SA-20 disinfectant worked well. That's also why the fall applied treatments had more algae than the check.

What next? I'd like to look further at Kocide and perhaps some disinfectants next spring. I'll also be looking for some growers who will be interested in trying the Kocide. Unfortunately it looks like if you want to control algae, you need to treat for it the last 2-3 years before harvest every spring. Once it occurs, there is nothing you can do about it. Treatments will be harder to make on large trees growing together, and in fact this is where we find the most algae. So keeping a good spacing between trees is important.

More Info on Fall Needle Shed

Jeff Owen sent me the following information to further discuss what's happening with fall needle shed:


Stressed Fraser firs will shed interior needles in late September or October. It usually occurs right in line with fall color on hardwood trees. Usually it is a sign of drought stress, but there may also be a fertilizer deficiency or toxicity contributing to the problem. We have not been able to point to a single nutritional problem contributing to interior needleshed. But I have seen internal needle shed in fields that have low phosphorus, or calcium, and/or very high manganeses or sulfur. 

I have observed several fields where the needle shed is widespread on the southwestern aspect and very light as the field shifted to more of a northern aspect. Even a subtle difference in aspect made a big difference in this problem. In a drought stress year, most growers will have 1 to 5% of this problem in their older trees, but I have seen one or two fields with as much as 30% of the trees affected.

Needle loss problems seldom show up before trees are of a marketable age and size.  Trees greatly increase the amount of foliage with each progressive year.  This creates an increasing demand for water and nutrients.  Factors which may have been adequate or marginal for a smaller tree become limiting as the tree grows.  The failure of symptoms to be expressed in younger trees has often lulled growers into complacency only to be surprised by needle loss in trees already tagged for market.

When needles shed out to the new buds in the fall, I think it is a different scenario. In that case I have observed 3 different factors in play: salt, calcium deficiency, and Phytophthora root rot.

Salt injury at some time in the current year can cause needle loss all the way out to the bud typically without killing the branch or bud (although sometimes they die too). I have seen late fall needle loss and grey-black necrosis in the bark and wood of branches that were spring fertilized with "plops" of 10-10-10. Sometimes the whole tree sheds, but sometimes only one side or a coil of branches climbing up the stem from damaged roots will lose needles.

Calcium deficiency will induce fall needle loss in the top or middle of a mature Christmas tree. I have seen white pine and Frasers with similar symptoms in the same field. All the needles on a branch can turn bright yellow, then brown, then drop off. The branch and buds live although growth can be stunted in the following year. I have seldom seen more than 1% or 2% of trees with symptoms of calcium deficiency. Yet these trees may reflect a field-wide deficiency. The concern has been that other trees in the field that showed no symptoms prior to harvest could shed needles after harvest either on the retail lot or in the  home. Dr Hinesley and Dr. Shelton conducted unpublished research that suggested this was the case.

The third root cause of total needle loss that I have seen was Phytophthora root rot (PRR). Usually, Fraser firs that die of PRR hold on to their needles a long time, but sometimes in the fall when the diseased trees have been stressed, green trees will shed out just like they do with a calcium deficiency. Only healthy roots can actively take in calcium, so it makes sense that PRR can contribute to the expression of calcium deficiency.

In all of this there are few proactive steps to take. In terms of the imediate harvest, buy a shaker machine to remove interior needles on trees that are still salable. For the future, take a soil sample and fertilize your farm according to the reports. Don't let market trees go to harvest short on calcium.

Fall Needle Shed

I'm getting out of my comfort zone talking about fall needle shed. I don't think we have a good explanation as to why it is happening. It is certainly associated with stress and is worse in some years (like this one) and in some fields than others.

Of course some needle shed occurs every fall. Usually it's the 4th or 5th year needles. The problem occurs when it's the 3rd, 2nd or even the current year's needles. That's when tags start coming out of trees!

These photos are ones I took with Jerry Moody on Friday at a high elevation farm in Avery County. The site was above 4,000 feet, and it was very windy -- that means a stressful site. Though these pictures were taken in Avery, I've heard of a lot more problems in Ashe County where it has been drier this summer and fall.

This tree had only a few areas that had discolored needles.

This tree had excessive shed throughout the whole canopy. It was a very heavy density tree, so it was hard to see from the outside, but it will still impact if this tree can be sold this year.

In some instances we've seen trees like this with current year needle drop that were due to root injury. Fertilizer burn can be one cause of root injury, but this particular field had not had any fertilizer applied since the spring. The shoots of this tree appeared to be healthy, as did the buds for next year. Root loss can also be caused by drought. Fraser fir, being a seed-run crop, will have individual trees that are more susceptible to drought than others.

I've had some calls from growers that are concerned that scales are causing this discoloration. At this site, there were no scales. If in doubt, look at the shoots of several trees. Turn the foliage over to look for the presence of scales. Most of the fall needle problems have not been associated with scales.

Advice for the grower? Keep on top of your fertility. By fertilizing according to soil sample results, hopefully you can avoid many of these problems. If the problem develops, take soil samples and plant tissue samples of healthy verses trees with shedding needles. And get your County Extension Agent involved.

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.