Movento and Rosette Bud Mites

Field where Movento applied in Avery County.

On Friday, Jerry Moody and Doug Hundley with Avery County Extension helped me evaluate rosette bud mite control in a grower’s field. I reported on this study on June 15. Then I just pulled some shoots at random to see if I could find any rosette bud mites. But now you can clearly see which buds look like rosette buds and if there are living mites present inside the bud.

Currently our best control has been to apply Dimethoate when the new growth is out 4-6 inches. A few growers have also tried Mavrik during that time frame with some results. But these have always been with a high pressure application.

Some growers have gotten good control with Dimethoate using a mistblower if they use a lot of water per acre (50+ gallons) and/or treat twice during that June treatment window. We were interested in trying the new systemic material, Movento with a mistblower.

Don’t confuse Movento and Safari. They are two different chemicals from two different chemical families. The active ingredient in Movento is spirotetramat. It is labeled at 5 to 10 ounces per acre.

The following two statements are from the label:

“Movento is a suspension concentration formulation and is active primarily by ingestion against immature target pest life stages. In addition, fertility of adult female target pests, such as aphids and whiteflies, may be reduced.”  This means that the pest has to feed on the plant having Movento in it to work. It also means that it will take some time for the product to work, as it is affecting pest development and fertility.

“Movento must be tank-mixed with a spray adjuvant/additive having spreading and penetrating properties to maximize leaf uptake and systemicity of the active ingredient within treat plant.” We have successfully used the adjuvant Liberate (which also makes droplet size larger, making it a good choice for mistblowers) and a 1% horticultural oil solution.

When Jerry and I tried this product last year for twig aphid control, we saw one tree that had rosette buds that didn’t have any following treatment. Since we were treating in mid April, it appeared that the systemic action of the Movento was getting into the tree and preventing the rosette bud mites from developing.  It had time to work throughout May and into June to control the mites.

This spring, we got Clay Cutherbertson in Avery County to apply the product with his mistblower. He treated in April using 10 ounces per acre and about 70 gallons of water per acre. Friday we went through those blocks, and found very few trees that looked like they had rosette buds on 2011 growth, and those few buds had no live mites in them. (Actually I did see one live mite under the microscope, but it was in a fully formed, normal bud and could no longer create a deformed rosette bud).

This is just one study in one field, but it looks very promising. A spring application of Movento with a mistblower may well control two of our most difficult to control pests – balsam woolly adelgid and rosette bud mites. Twig aphid control with Movento is only fair, but in fields that had twig aphid control from the fall, or by adding another material such as Talstar which works well against twig aphid (that’s why Clay did), you can control multiple pests in the spring.

Like most studies, this little test creates some more questions. Does Movento have activity against rust mites which are quite similar to rosette bud mites? Can you treat with Movento any time of year and control the mites inside the bud? These are some things we’ll be looking at in the future. Keep checking back to the blog for more information about Movento and other chemical controls.

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.

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.

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.

Putting Out Systemics

Today Jerry Moody and I put out Movento and Safari, both systemic materials, at two different farms.

Movento is a systemic that is supposed to be quite mobile in the plant. It requires the use of an adjuvant to help it be taken up. We used a product called Liberate. The last couple of years that we've worked with Movento it provided great control of balsam woolly adelgid, decent control of twig aphids, but hardly any control of elongate hemlock scale. In one tree last year, it also looked like it control rosette bud mites so we were interested in that too.

This year we applied Movento in two fields that had it all -- twig aphids, scales, rosette buds and woollies. We used a rate of 10 ounces per acre of Movento and 2 pints per 100 gallons of Liberate. Both of these are the highest rates. At the one field the trees were small and we sprayed about 200 GPA. The other field had denser, larger trees so we used double that.

The Safari applications were the new trunk sprays. These may control both woollies and scales but we don't anticipate them having any activity against twig aphids or rosette bud mites. We used a rate of one pound per acre.

Dr. Richard Cowles from Connecticut has been doing this technique for several years. He talked about it at the NCCTA in Boone this spring. He has been recommending an application with a backpack sprayer, wetting the trunk of the tree from about 10 inches to the ground. The rate he uses is 3 1/2 ounces Safari in 3 gallons of water. You use 1 ounce of this solution on each tree, treating the tree from both sides. That is because the Safari will move up the tree, but not from one side to the other.

His recommendations are based on lighter density trees that are also butt pruned. That's not the type of tree we grow here in North Carolina. So we only used this backpack application at one farm. We decided to also apply Safari to the trunk of the tree North Carolina style! We treated the trees with a high pressure sprayer. Again we aimed for about one pound per acre, treating each tree from opposite directions. But since we are putting out more water per tree (about 50 gallons per acre) we mixed the Safari differently. We ended up using 6 ounces of Safari in 20 gallons of water. This should treat 4/10ths of an acre. This type of application went very quickly.

A short video of Jerry applying the Safari this was is seen below. The respirator is not required on the label. On a couple of trees he sprayed twice -- that's because he missed the trunk the first time! He said you could tell when you hit the ground and not the trunk by how it sounded.

At the one farm we also used an Onyx knock-off called Sniper. This is a bifenthrin product (same active ingredient as Talstar) but it is mixed differently. It uses a different carrier, and it has 2 pounds active ingredient per gallon instead of 0.67 pounds. That means you don't need as much. We tried using the same amount of chemical as the full 40 ounces per acre of Talstar -- that ends up being almost 13 ounces of Sniper. We haven't seen that bifenthrin gives much control of scale in NC, but Cowles has said that the Onyx works well, so we'll see.

Unfortunately, it may take several months before we know how well any of these treatments work. I'll keep you posted.

Spring Rush & Rosette Bud Mite Treatment

Sometimes kids seem in such a hurry to grow up. It seems like that's the way it is with this spring! All at once, all the Fraser fir buds are breaking everywhere. Hope no one got any frost earlier this week.

I just wanted to remind folks that if you have to treat your trees for rosette bud mites, you might end up treating earlier this year than you usually do. You want to wait until ALL THE TREES in the block have broken bud. But  theses late breakers, might be all out by the end of next week instead of into June. Let your trees be your guide.

A singe treatment of either Dimethoate or Mavrik will control the rosette bud mites. For more information see: Rosette Bud Mite on Fraser Fir -- CTN 018A.