The Value of Christmas Trees

"...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 stop toward the will to plant and care for them (Arthur Sowder, US Forest Service, 1949)."

Thursday, June 30, 2011

Organic Christmas Tree Powerpoint

Fertilizer for the Extension Organic Demonstration
I was scheduled to give a talk at a Southern Christmas Tree Conference at the end of May in Atlanta. The conference was canceled, but I had already put together the powerpoint. It was a short talk on the possibility of growing organic Christmas trees. Thought some folks might enjoy looking at it. It's in a pdf format.

Organic Christmas Trees

Any thoughts? Questions? Anyone interested in starting organic Christmas trees?

Wednesday, June 29, 2011

Trip to the Roan

Roan Mountain is one of my favorite places. I hadn't been on the mountain for three years, so thought I would travel up there last week to see how the trees are looking.

The Roan has changed tremendously through the years. I have a bit of information about it in my history of the NC Christmas tree industry at: Chapter 2: Why Fraser Fir? This chapter goes into a lot of the natural history if Fraser fir if your interested. As far as Roan Mountain is concerned, logging had stopped by 1937 and by 1941 the US government had purchased the property. Wikipedia has a pretty interesting summary of Roan Mountain as well. Jennifer Bauer Laughlin also wrote a good book on the Roan in 1999 called "Roan Mountain: A Passage of Time."

Balsam woolly adelgid was first detected on the Roan in 1962. Trees were protected in 1963 to establish a source of seed for the fledgling Fraser fir Christmas tree industry in North Carolina. The following is an excerpt from Chapter 5: Early Days: the 1960s.

Spraying trees on the Roan in 1964.
From a forest service brochure dated 1964.
"A 25-acre seed production area was established by the US Forest Service and NC Division of Forestry (Johnson, 1980).  “Three hundred trees were marked and subsequently included in the protection zone” (Johnson, 1980, p. 16).  Those who worked on the project included Dwight Brenneman, Nursery Superintendent of the Edwards State Forest Nursery in Morganton, Bob Kellison who had been hired that year as a forestry faculty member, John Gilliam, Leonard Hampton and others presumably with the Forest Service. Trees had been thinned in the fall of 1963 to increase cone set, but the shallow rooted habit of the Frasers made them prone to blowing over (Green, 1965).


Trees were originally sprayed November of 1963 with BHC, a precursor to Lindane, and more trees sprayed along the 2 ¼ mile Balsam Road in the summer of 1964 (Green 1965). Treating these areas with insecticides and other areas in natural stands cost an estimated $100 per acre (Claridge, 1963). “Spraying was discontinued in the seed production area in 1974 after many trees had been lost to windthrow” (Johnson, 1980, p. 17). "

Roan Mountain had been the industry's most important seed source for many years. In recent years, research conducted at NCSU has determined that Roan Mountain trees were genetically inferior to other seed sources.

People line up to pull seedlings from Roan Mountain in 1978.
Collecting seed from Roan Mountain in 1997.
The Roan Mountain seedling pull has been discontinued due to lack of interest.

In 2008 when I went up to the Roan to view the rhododendron's blooming, I was struck with how healthy the trees looked on the road back to toll house. Sadly, this year most of those trees were dead. The following video highlights the regeneration of the Frasers, and the larger trees which have finally succumb to the balsam woolly adelgid and other stresses.

video

Young trees are naturally less susceptible to BWA because they produce juvibione, an insect growth regulator. This is different from hemlock woolly adelgid which attacks all ages of eastern hemlocks. Read more about juvabione on Wikipedia!

So what kinds of pests did we find on the Roan last week? We found balsam woolly adelgid, rosette bud mites, and balsam twig aphid damage. We also found some strange needle problems which I haven't seen before. We didn't see any elongate hemlock scale.

Rosette bud on the Roan.
Twig aphid damage on the Roan

Unidentified needle damage on the Roan.
We also didn't see many Fraser fir cones. There were red spruce cones developing. This seems odd because it's been a rather big year for cones in growers' fields. Guess it has to do with the heat and dry weather last year in June at lower elevations. I'll try to find some weather archives from the top of the mountain. At least I got some photos of red spruce cones. I didn't have any.

Red spruce cones
I also got to see the Gray's lilies starting to bloom. Always a pleasure to visit the natural stands of Fraser fir.

Gray's lily
The crew that went up on Roan Mountain included Brad Edwards, Jeff Vance, Jerry Moody and  my daughter Emma.

Thursday, June 23, 2011

Elongate Hemlock Scale Lifecycle

In talking with folks, I find that people are confused about the lifecycle of the elongate hemlock scale.

It is a bit confusing. The same insect can be white (for the males), brown (for the females) and yellow (for the immatures). It's hard to know if they are alive or dead. So here's a bit on the lifecycle that will hopefully make things clearer.

Life for an elongate hemlock scale starts out as an egg which is found under the protective scale of the mother. Here is a photo of the mother flipped over and broken into to show the eggs and the same photo labeled.



These eggs will hatch and the crawler will move out from under the mother scale and find a place to settle down. I actually got by accident a photo of a crawler leaving the mother. It is below. See the crawler at the bottom of the picture? Once again, everything is labeled in the second shot.



The crawler moves around until it finds a place to settle down and start moving. There it will molt, and start creating the scale covering for itself. If it is male, eventually it will fly away  so it can mate. That only happens when it is mature. If it is female, it will never move again.

The crawler is the small yellow thing.
The nymphs settle down, and then they produce the adult scale behind them. Here is a photo of one female scale. The yellow portion is the nymph part of the female, and then the brown part is produced.There aren't two scales, just one. It is all white around it because the scale has grown under the waxy cuticle of the needle. It is also almost impossible to tell if it is dead or alive. Under a microscope you can poke it with a pin and it will be moist. This one was alive when I took the photo.



The males are white. They develop into a winged insect that flies off to mate with the stationary females. You can almost think of the white scales as ultimately being a cocoon in which the male is developing. So often when you see the white scales, they are empty because the adult male has already flown off. The adult male is pictured below. This isn't my photo, but it's all I've got of the males.


Now let's put time into the picture. When does all this happen? The following are observations made by Paris Lambdin, a researcher in Tennessee.


          “EHS has two complete overlapping generations per year at sites within the southern Appalachians.”  My comment -- That means that you can find all life stages virtually any time through the year.
          “The spring peak for crawler emergence occurred in June while the fall peak occurred in late October into November.”  
          “Fall peak emergence for males occurred in August, coincident to the highest number of adult females.”  My comment -- That's why we see a second "wave" of white coming onto the trees in August. That's the second generation of males being produced.
          “Gravid adult females were most numerous in late May and October—November.”  My comment -- Gravid means they have eggs.
          “Females have three stages of development while males have additional prepupal and pupal stages.”  My comment -- That refers to the number of molts each sex goes through before maturity. For females, they are mature when they can lay eggs. For males they are mature when they emerge and fly away.
          “Each female produced 12-16 eggs which hatched over time.”
          “Males do not feed and live only 24 to 72 hours upon emergence. Although capable of flight, males tend to walk across the needles seeking out females for mating.”  My comment -- These are the adult males with wings that have emerged from the "cocoon." Some folks were finding the adult males when they were beating the foliage in the spring looking for twig aphids.

Other observations from scientific literature include:

          All life stages found any time of year (Davidson and McComb 1958) – eggs laid throughout growing season
          Mature females may often live for more than one year. My comment -- Isn't that great!
          After a month, the eggs hatch and the first instar nymphs ("crawlers") emerge and migrate to the underside of new needles. 

No wonder people were having a hard time figuring out the life cycle. It's complicated! If anyone has any questions, please let me know.

Ways to Put Out Safari: Part II

On Tuesday Jeff Vance, the County Extension Director in Mitchell County, and I applied some Safari to trees in Little Switzerland. Hopefully this will be on the 2012 Summer NCCTA tour.

We applied Safari 3 different ways:

  1. With a backpack sprayer to the lower 10 inches of the trunk.
  2. With a high pressure sprayer to the lower 10 inches of the trunk.
  3. A full trunk application with a high pressure sprayer.
Sadly our study site received a great deal of rain just an hour after application so the chemical was probably all washed away. But we plan on repeating this in another couple of weeks, and making more applications like this later in the year. We already made a similar application on May 20.

Here is a video of Jeff applying the Safari to the entire trunk. Hope it doesn't make you seasick!

video

I think that the full trunk spray will be the better way to apply Safari to Frasers in North Carolina. As you can see, these are large, dense, beautiful trees. It is hard to target just the base of the trunk. We didn't even attempt it with a backpack sprayer -- those trees on other side of the road, pictured to the right of the sprayer.
Field where Safari was applied to the base of the trunk with a backpack sprayer.
Even though the trees were smaller, it was still hard with just a backpack sprayer to make sure I was coating the base of the trunk. I used a hollow cone nozzle which I've been using to apply Safari to the trunk of large hemlocks or Frasers. I ended up using about 2 ounces of water per tree to make a thorough application. That's twice as much water as Dr. Cowles was recommending, but I feel like it was necessary to get good coverage. Even with a high pressure sprayer, sometimes there was full coverage all the way around the base of the trunk and sometimes there wasn't.

Though the full trunk spray will take more water, and it will require a high pressure sprayer, it is certainly much faster, easier and cheaper than a normal balsam woolly adelgid treatment that folks have been doing for years. It will just require calibration to apply the targeted 1 pound per acre application rate.

Now is all of this effective at controlling scales and woollies? We still don't know. However, the full foliar application with a high pressure sprayer has been shown to be effective against both pests this time of year. This is with a lighter spray than typically used for woollies -- more of a twig aphid spray. We asked the grower to do this in another portion of the field to make that comparison. 

Stay tuned for more results!

Monday, June 20, 2011

Further Results from June 2010 Safari Treatments


So what are all these people doing? Evaluating balsam woolly adelgid (BWA) control of course!

On June 28 of last year, I reported treating some Frasers at the seed orchard near Mount Rogers with Safari using either a soil or trunk application. See post.

Safari (which is still not clearly labeled for Christmas tree application by the way), can be applied with many methods. It can be sprayed on the foliage. It can be applied to the soil. It can be sprayed on the trunk.

We've seen Safari work very well for BWA control spraying the foliage, but these last two methods have been looked at more thoroughly for hemlock woolly adelgid control, though there has been some work conducted in Connecticut by Dr. Richard Cowles looking at elongate hemlock scale control in Fraser fir. To my knowledge, Cowles hasn't looked at BWA control with Safari.

Safari is a really good systemic. But for it to control BWA when it is applied to the soil  it would mean that it was taken up by the roots and moved from the vascular system into the tree bark where the adelgids are feeding. With a trunk application, it has to make one more move -- from the bark into the vascular system and back out to the bark throughout the tree.

Two years ago when Jeff Vance and I tried soil applications of Safari, it seemed to work. But there was also a lot of rainfall at the time.

Last summer it was really dry. When we went back to Virigina in the early fall we didn't see any control with the soil or trunk applications. But I was hoping that control would come later, and last Friday, June 17, I went back to make more observations. Brad Edwards and Teresa Herman came with me and helped me collect samples.

The following pictures are of Teresa climbing up above where the Safari trunk applications were made to get a section of bark, and me looking at the bark samples. (I poke the adelgids with the tip of a pocket knife while looking at it with a magnifying lens).



This time we did see some control with the Safari, but only at the highest rates. We also only saw really good control with a soil drench using the highest rate of Safari, and not with the trunk application (which is of course far easier).

There were a couple of problems with this little study. The first was the lack of rain. There wasn't much after the applications were made, so I would like to repeat the study to see if we can get better results. Also, we might not have used enough water with the trunk applications.

But, even if these work, the rates are rather high. The high rate for the Safari trunk spray is 24 ounces in 1 gallon of water. If you use the recommendations which Valent has for HWA control, you would use only 12 ounces in a gallon, but then apply 1 quart of this spray for a tree that has a 10 inch trunk diameter. That gives a rate of 3 ounces Safari per 10 inch trunk diameter. The rate on the soil drench is 1 to 4.2 ounces per 10 inch trunk diameter. And remember that you can't exceed 2.7 pounds Safari per acre per year -- but then at $115 a pound, who could afford it? With these seed orchard trees, you would quickly exceed the rate.



The foliar sprays are 4 to 8 ounces per 100 gallons -- much more affordable and probably just as easy to do. Perhaps we can get by with a bit less coverage and still get control.

In any case, keep looking at this blog for more updates on how Safari is working with different application methods and timing.

We had a visit from some Mount Rogers ponies on Friday!

Wednesday, June 15, 2011

Peek-A-Boo

Yesterday Jerry Moody and I evaluated some treatments for rosette bud mites that a grower made with a couple of new products -- Movento and Mavrik. Movento, if you will recall, is a new systemic made by Bayer. Last year it looked like one of the trees that had rosette buds recovered after a spring Movento treatment. Mavrik Aquaflow is a synthetic pyrethroid that Jerry Moody has had a couple of growers use for rosette bud mites. The Avery County grower used a mistblower to apply the products. To date we've never seen any mistblower applications work that well for rosette buds, though some folks have gotten good enough control with a mistblower using Dimethoate. The hope was that the Movento would work better through a mistblower since it is such a good systemic.

Of course the buds for next year are just forming now, and it is too early to go through a field and pick out the rosette buds. So Jerry and I randomly pulled some new growth on trees that had rosette buds, and I looked at them under the microscope to see if any mites were present in the developing tissue.


The results... Not going to say yet. Sorry. Still too preliminary. But I would like to share this photo I took at the Watauga Extension office of a rosette bud forming. This is a shot of a bud sliced down the middle from top to bottom. You can see that there is a cavity forming where the shoot should be and about 10 rosette bud mites -- and maybe even an egg. The same photo is seen below with everything labeled.



And obviously, since I was finding some mites, one of the products didn't work -- but one seemed to! I think I'll go back next week and collect more samples and spend some time taking photographs which I'll share on my blog. It will probably be mid July before I can give the results of this little study after the rosette buds have clearly formed and I can see throughout the block how well things are working. So stay tuned.

Monday, June 13, 2011

So Why do Spider Mites Crash?

It  brings to mind a car crash but of course that's not what I'm talking about. I'm talking about a healthy, reproducing population of spider mites that goes into a sudden decline.

I hope you've been able to witness it happening, because it gives you a good feeling. After all, you are getting free pest control. For once, nature is being a help instead of a problem. But how does it work?

Close-up of a female spruce spider mite.
Spider mite numbers decrease for a number of reasons, but it usually revolves around the weather. Spider mites like it hot and dry. Why? The warmer it is the faster they mature and reproduce. They also prefer dry weather because wet weather keeps most of their eggs from hatching. Sometimes you'll even see the mite eggs and even the mites themselves turning black as a fungus consumes them.

But humidity also plays another role. The predatory mites that feed on spider mites do better in humid conditions. So wet favors the good bugs (predatory mites) and dry the bad bugs (spider mites).

For a view of predatory mites, click here! This publication is for greenhouse growers, but the mites are the same.

We've already been seeing spider mite numbers rise and fall this spring in Fraser fir fields in western North Carolina. There are still a few eggs present in some of these fields which might allow the spider mites to come back later on in the summer or fall. In fact, if the fall is dry that is when spider mite numbers really tend to rebound, making them a problem on harvested trees. But for some of these fields, no further action will be necessary.

So how will you know if spider mites are rebounding? You scout, of course. Scouting for mites doesn't have to be a lot of work. Just going out and checking a few trees every month or six weeks -- especially those prone for mites -- will help you keep track of their numbers. Look at some shoots with a hand lens. That's the best and easiest way to look for mites.

Scouting for spider mites with a hand lens.

For a complete review of spider mites and their control see the Christmas tree note #29: Spruce Spider Mite on Fraser Fir.

Wednesday, June 8, 2011

Going Mobile!

The Fraser Fir IPM Blog has gone mobile!

Now when you access this blog from your mobile phone, you will get a slick new look that will allow easy viewing when you are in the field or on the go.
Enjoy!

Wednesday, June 1, 2011

Some Results on Pest Control

We're seeing more twig aphid damage than I anticipated. After all, it wasn't easy to find twig aphids in April. Plus we had lots of rain and cooler temperatures which tend to reduce the survival of the aphids. But they are well adapted to western NC, and they have ended up causing some damage.

BUT... with all the rain, a lot of the damage is disappearing. I spoke with Bryan Davis who told me that he is seeing less needle curl in fields this week even than last week. Thanks to the rain, the majority of this curl will go away.

This leads me to some data to report from my current studies.

FALL TWIG APHID CONTROL: Last fall, Jerry Moody and I treated some trees October 18, 2010. Really we were trying to see how late you could treat in the fall and still control elongate hemlock scale. But I also wanted to see if the treatments would control twig aphids the following spring. We tried Safari (applied to the foliage with a high pressure sprayer at 8 oz/100 gallons), Lorsban, and the standard Dimethoate + Asana.

I did evaluate scale control this spring, and none of the products worked well. This wasn't surprising as mid October is probably too late to get much scale control. However, I also evaluated BTA control this spring with these fall treatments and those results are pictured here.

Remember that I evaluate twig aphid damage by either walking around the entire tree (which makes me dizzy!) or working with a partner. For these observations, I worked with Jerry Moody. We walked on either side of the tree and estimated the percentage of 2011 new shoots with needle curl each on our respective side -- then we come to an average figure for that tree. These result in the numbers in the first column (% shoots with curl) -- averaged for all 20 trees. The next column has the percentage of the 20 trees with at least SOME needle curl. The third column has the percentage of 20 trees with 10 % or more of the needles curled. This is the point where most growers tell me the damage is bad enough to affect the value of the tree. Of course remember that the needle curl will decline over the next several weeks, so all of these numbers will go down. Still, the comparison now when the damage is at its greatest tells us how well the products are working.

Obviously, neither the Lorsban nor the Safari are giving us any twig aphid control when applied in the fall. The Asana + Dimethoate worked well, though not perfectly. In fact, Brad Edward's observation this spring has been that the Asana in the fall isn't working quite as well as the Talstar applied in the fall. It works, but a bit of curl gets through. These results bear this observation out, and in fact the first year I did this type of work at Omni Farms, that was our observation. Still, the Asana + Dimethoate gives good enough control and it would be more effective against scales.

SPRING CONTROL WITH SYSTEMICS: So how well does Safari and Movento work in the spring? Jerry and I applied these products at two farms, treating on April 18, 2011. In this instance we applied the Safari to the base of the tree trunk and not the foliage, using a rate of 1 pound per acre. At two farms we did this with a high pressure sprayer, and at one farm just with a backpack sprayer. The Movento and bifenthrin are applied with a high pressure sprayer to the foliage.

The results again demonstrate that Safari isn't giving us twig aphid control. Practically all the trees had some needle curl when treated with Safari. The Movento gives fair control. A lot of trees have some curl, but hardly enough to worry about. The bifenthrin is of course the best.

At these two farms there was also scale and woolly adelgid. We will be looking at the control of these pests later on in the summer, so stay tuned!

OTHER OBSERVATIONS THIS SPRING: Once again, several people I've spoken with this week are commenting on spider mite activity. The rain is reducing mites to some extent -- probably by increasing predator mite activity, but it is still important to scout for spider mites and make sure they don't damage new growth. The good news? All of this hot weather should be taking care of any rust mite issues!