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)."

Wednesday, June 30, 2010

A Good Day for Scales to Die!

At least I hope so!

Today I sprayed 4 different materials for EHS control. I applied the materials with a backpack mistblower, using about 100 gallons to the acre. I treated 40 trees each with either:

  • Safari @ 8 oz/100 gallons
  • Movento @ 10 oz/acre + Liberate (an adjuvant) @ 2 pts/100 gallons
  • Lorsban @ 1 qt/acre
  • Dimethoate @ 16 oz/100 gallons + Asana @ 10 oz/100 gallons
The population was ready for control. I collected a sample and looked at the percentage of individuals that were either males (the easiest to kill), nymphs, or females (the hardest to kill). Only 14% of the population were females with 24% as males and 62% as nymphs. I'll come back in a month or so to see what kind of controls I got.

The field I treated was part of a study to see how quickly the scales spread. On July 14, 2008, Bryan Davis and I evaluated 361 trees to see which ones had scales. We flagged infested trees and made a map. At that time, about 1/2 of the trees had scale, though most of it was only a shoot. Only 4% of the trees had moderately heavy scale.

We couldn't go back last year because the grower had put lime on the trees, and it was too hard to tell what was lime and what was scale. But I went back yesterday before treating today. 

Now 95% of the trees have scale and 40% have it pretty bad. But even on trees that have had scale heavy for two years or more, they don't look that bad (one is pictured at the end of this blog along with a photo of the field). I do think the trees that have had scale heavy have weaker bottoms, but they are still growing well.

So how much does EHS really damage trees? The jury is still out. I think we can keep the scale "beat back" though never eliminating it completely. For most growers who aren't shipping to California or another country, that will probably be good enough. 

Monday, June 28, 2010

Some Success with Safari

On January 25 in this blog, I reported some success with controlling balsam woolly adelgid (BWA) with Safari (dinotefuran). Safari is a neonictinoidal insecticide similar to Merit (imidacloprid), but far more water soluble. Safari also controls elongate hemlock scale.

Spring treatment. This spring, Buddy Deal sprayed some trees with Safari + Dimethoate. Remember that Safari doesn't control twig aphids or mites, so the Dimethoate was for twig control. They used a high pressure sprayer, but put out the materials with a light spray intended for twig control and not for woolly control. They didn't soak the trees or the trunks. The rate was the high rate of 8 ounces per 100 gallons which is the high rate. The field is pictured here.

We went back about a month later, on May 20, and the woollies were still alive. But it had been rather dry, and we decided to go back in another month.

On Friday June 25, Bryan and I went back again. This time the woollies were all dead -- both on the trunk of the tree and on the buds and branches. We didn't find any live adelgids at all.

I'll keep an eye on these trees over the next 12 to 18 months to see if the woollies come back quickly or if the control is long lasting.

Seed orchard treatments. We've been putting out Safari for BWA control in seed orchard trees as well. On June 17, we treated trees at the Mount Rogers seed orchard at Grayson Highlands State Park in Virginia. This will be on one of the summer tours for the NCTA/NCCTA meeting in August.

We treated 3 trees with one of 5 treatments:
  • Safari soil drench at the high rate of 4.2 oz/10 inches trunk diameter
  • Safari soil drench at the low rate of 1.0 oz/10 inches trunk diameter
  • Safari trunk spray at the high rate of 24 oz/gallon
  • Safari trunk spray at the low rate of 12 oz/gallon
  • Merit soil drench at the highish rate.
The trunk sprays are interesting. The material soaks up through the bark and travels through the tree. I sprayed with a backpack sprayer using a hollow cone nozzle. I sprayed from 5 foot high on the trunk down to the root flairs, wetting the entire trunk, but not to runoff. If the low rate works (the high rate would be way too expensive), it would be a quick easy way to control woollies in seed orchards or very large trees (greater than 12 foot). I will check the control before the NCTA meeting.

HWA treatments with Safari. Jerry Moody and I also treated hemlocks with these trunk sprays using either Safari or Merit. In this case we also added Pentrabark to increase penetration through the bark. 

Elongate hemlock scale control. I also plan on treating some trees for elongate hemlock scale later this week. I'll compare the Safari to Dimethoate + Asana, Lorsban, and Movento.

I'll keep everyone posted of how well things work.

Some June Pests

Went out last week and found several June pests that might be of interest to folks.

Elongate hemlock scale. Scales are making their way onto the new growth. If you treated this year in the spring, or sometime last year, and you aren't seeing the scales get on 2010 growth, that means you have pretty good control. This is a photo of scales on 2010 growth.

At this particular field, the grower had treated with Asana + Dimethoate with his mistblower before bud break this spring. Though there was still live scale, it hadn't spread to new trees, so we counted the treatment as a success, since it was far less expensive than spraying with a high pressure sprayer. The grower was going to cut out the worst trees for scale (he'd have a hard time selling them anyway), and will retreat in a few days with his mistblower while the crawler number is at its peak. Hopefully that may also give him twig aphid control next year.

Balsam woolly adelgid. Woolies have also moved onto the 2010 growth. This photo is of nymphs already on the new growth. There is already swelling too. These will molt in place to the adult within the next month and start laying more eggs.

This particular block of trees had been treated with dimethoate in the spring. No control of woollies. The grower will spray with Talstar sometime this fall.

White pine cone beetle. The pine cone beetle is an infrequent pest of Fraser fir, borrowing into usually the first whirl of branches and making a shepherd's crook. Sometimes you can still find the black beetle in the tree. The two photos are of the entrance hole and then of the beetle. These pictures were taken in Ashe County last Friday. I haven't seen any of these pests for several years. They are usually only a problem when there aren't many white pine cones, which are their preferred food. When you find them, they have already caused as much damage as they are going to, so they are only a novelty and nothing to worry about. Shearing will take care of the problem. Bryan found these. Jerry Washington was the first one to find them years ago.

Leaf footed seed bug. The last interesting bug Bryan also found on a Fraser fir cone in some Christmas trees. I think it is a leaf footed seed bug that will feed on Fraser fir cones. You never know what you'll find in a tree field!

Tuesday, June 22, 2010

Spider Mites

Bryan Davis was telling me that he's seeing several fields where spider mites are becoming a problem. One of the fields we had scouted thoroughly in April without finding any mites. I've also seen some spider mite activity in a couple of fields. Though it's been wet and humid, it's also been rather warm (understatement, yes I know!) which makes mites more active. So if you haven't had a chance, now would be a good time to look for spider mites before the shearing season swings into gear and they end up causing damage.

Monday, June 21, 2010

Cryptomeria Scale

Cryptomeria scale (Aspidiotus cryptomeriae) has been a problem on Christmas trees for several years in Pennsylvania and other states, but not in NC until now. Alan Durden found some on Fraser fir in Macon County, which I had the opportunity to visit last week.

The trees were from 4 to close to 12 foot tall, not far out of Franklin. There was a very heavy incidence, but many of the scales didn't look healthy. Some had fungi growing on them. Others appeared to have been feed upon.

For those of you familiar with elongate hemlock scale, the life cycles and control of these two scales are quite similar. The biggest difference is that the cryptomeria scale is more rounded in shape. We found nymphs on the new growth on some of the trees.

We also found a lot of the twice-stabbed lady beetles (genus Chilocorus) -- both adults and nymphs. Richard Cowles and others reports that these are good predators for scales. I have never seen them feeding on elongate hemlock scale, and in fact usually only see about one a year, but there were dozens on these trees.

Because of the predators and because the grower only has a few trees, we decided to wait a month before deciding what to do for control.

Symptoms on the top of the foliage are similar to elongate hemlock scale. They aren't found on all the infested trees just like with EHS. I didn't see any of the white fluff that gets on trees with EHS. That probably doesn't occur.

This is what the scale looks like under the foliage. For a clearer picture, google the scale.

Here is one of the lady beetles. They are real pretty.

Tuesday, June 15, 2010

Update on Endosulfan

Wayne Buhler, the pesticide coordinator for NCSU sent the following message out this morning. It is from Lee Davis with NCDA&CS about the fate of endosulfan. Nothing has been decided yet about how the product will be phased out, but Lee describes what usually happens. Again, when things have been decided, I'll let you know.

"Yes.  The way I understand it is that the EPA and the registrant are currently working out the details of how to cancel the product.  Usually, the EPA will post to the Federal Register a notice to cancel the product and give a date upon which the product is cancelled.  Usually, the EPA will allow product already in the channels of trade or in the hands of the end user to be used up according to label directions.  This is what usually happens, but each cancellation notice is unique.  So, it is not possible to say exactly what instructions might be in the cancellation notice.


Friday, June 11, 2010

Endosulfan (Thionex)

As of June, 2010, EPA has decided that endosulfan, the active ingredient to Thionex, poses too great a risk to workers and wildlife. Therefore EPA is taking action to end all uses of the product. You can read more about it at:

According to an EPA news release dated 6/9/2010, "Makhteshim Agan of North America, the manufacturer of endosulfan, is in discussions with EPA to voluntarily terminate all endosulfan uses. EPA is currently working out the details of the decision that will eliminate all endosulfan uses, while incorporating consideration of the needs for growers to timely move to lower-risk pest control practices."

I do not know anything more at this time, but will keep you posted.

Monday, June 7, 2010

Another Scale

In one Christmas tree field near Jefferson, Bryan Davis kept seeing a different kind of scale. We finally sent them in, and they were identified as the hemlock scale (Abgrallaspis ithacae). This scale is native to the US. It is closer to target shaped instead of elongate. It is not reported as being damaging to trees. The following image is from IPM Images. We will be monitoring this site to see if these scales develop into a problem.
hemlock scale, Abgrallaspis ithacae  (Hemiptera: Diaspididae)

Thursday, June 3, 2010


As more research is being done on the chronic effects of low level exposures to pesticides, it continues to be apparent that pesticide use can adversely affect the health of the pesticide applicator. That's why it's important that people wear the appropriate personal protective equipment, and even use more PPE than is required, especially when treating Christmas trees with a high pressure sprayer.

One of these pieces of equipment is the respirator. In my opinion, anyone treating trees with a high pressure sprayer should use a respirator. This is true whether you are using horticultural oil or a synthetic pesticide. Few materials require the use of a respirator on the label, but since you are continually walking through the spray, that is the best way to reduce exposure.

Some of the commercial applicators have purchased the helmets with motorized forced air which completely cover the head. These offer the most protection, and are the easiest to wear. They keep the worker cool, and don't require a lot of effort to breath through them.

But a lot of people still depend on either the full or 1/2 face respirator with attached cartridges which are certainly less expensive. However, there are several issues with these.

1. They don't cover the entire face, and in fact the ear canal is one area of skin that is particularly thin and will readily absorb pesticides. The rate of absorption is far higher than the skin on your palm or forearm. Using a hood on a spray suit will eliminate this problem.

2. Many people don't fit the respirator closely enough to the face. I've seen several folks wear respirators that just hang on their face. The respirator is supposed to fit snugly so that all air breathed in passes through the cartridges. And yes, when you do this, they will fog up. But, when the fit isn't snug, contaminated air can come in through the sides. If a man has a beard or mustache, this can interfere with the fit. In fact, it is best not to have facial hair when using a respirator.

3. The third issue then becomes one of applicator's health. Some people's lungs just aren't strong enough to pull air through the respirators.We all know how tiring it is to wear a hot spray suit and respirator and walk through trees spraying with a hose. You have to have good heart and lungs to be able to do this demanding work.

In fact, OSHA regulation 1910.134 requires workers be properly trained in using a respirator, that a fit test be conducted, and that the worker is certified by a doctor as being physically fit enough to use the respirator. These requirements have largely been overlooked in agricultural circles, but that may be changing.

So be safe. Check the fit on your respirator, and use it like it was intended.

Wednesday, June 2, 2010

HWA Control

OK, I know this is a Fraser fir blog, but I had to include a photo of these hemlocks. They are at my office in Mills River. I treated them 2 years ago for hemlock woolly adelgid with Safari using a soil drench, and they are still growing like gangbusters. We'll be looking closer at Safari for the control of balsam woolly adelgid.