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!

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!

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!

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.

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.

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!

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!

Ways to Put Out Safari

On Friday, Jeff Vance and I tried putting out Safari in some Christmas trees. We used either a backpack sprayer with a hollow cone nozzle, or a high pressure sprayer. With either sprayer, we were targeting the lower 10 inches of the trunk.

Unfortunately, I think the application was uneven. On some trees, there was good coverage all around the trunk. This is important because only when the entire trunk is encircled with spray will the entire tree get a dose of the chemical. But on other trees, the entire trunk was not completely covered.

Jerry Moody also tried applying Safari to his trees. In his case, he targeted the entire trunk of the tree, treating from both sides, and not just the base. He ended up using more water but he made a more dilute spray to target 1 pound of Safari per acre. And he thought he was getting excellent coverage, as well as moving quickly through the trees.

Next month when Jeff and I spray, I think we will compare different application methods of Safari using a high pressure sprayer -- treating just the bottom 10 inches, treating the entire trunk, and treating all the foliage lightly -- like a balsam twig aphid spray. That way we can find the quickest, easiest method of application. We hope to have this field on the NCCTA summer tour next year in 2012.