Time to Scout -- Time to Treat

Twig aphid numbers. If you have twig aphids in your Fraser fir Christmas trees in western NC, you should be able to find them now. They are still quite small, but they have all hatched out. So if you treated your fields last fall for Cinara aphids, you might be able to skip treating for twig aphids this spring. But the only way you'll know for sure is to scout.

The aphids go through several molts before becoming adults. At maturity, this first stage is called the stem mother and she will produce live young aphids which quickly build up the numbers. That's why it's so hard to judge how much damage there will be by the twig aphids. It's a function of how many aphids there are right at bud break, and how quickly the new growth of the tree elongates and becomes resistant to damage. This is all modified by the weather on a daily basis.

To scout, get your plates out and start beating foliage to assess twig aphid numbers. Be sure to use a hand lens as the aphids can be quite small. It's best to wait until the foliage is dry (a challenge for this week!) but if you're good at scouting and don't mind getting wet, you can find them about any time. If you're not sure how to scout, contact your county extension agent.

If you see more than an aphid or two in a block and the trees will be marketed this year, go ahead and plan on treating this spring.

Christy Bredenkamp beating foliage to scout for twig aphids.

Look with a hand lens as the aphids are often quite small.
These tiny aphids will be having babies in just a week or two.

There are at least 6 aphids pictured here along with round balls of honey dew. When scanning a shoot
with a hand lens, you can often spot the aphids by the ball of honey dew.

Rust mites. There are several fields where rust mites are a problem this spring. Mites aren't in every field. The best way to assess rust mites is to pull some of the smaller shoots of growth and scan the back side of the needles for the tiny mites. If you don't need to treat for twig aphids but mites are a problem, you might have to treat anyway. Mark infested trees and go back to them to see if the numbers are building and treatment is necessary.

Choose shoots like this to look for rust mites.
You can also look for twig aphids, spider mites, and scales when scouting shoots.

Flowers & bees. Purple deadnettle must really like the weather we've been having. It is blooming everywhere and on sunny days, it is bringing in the honey bees and bumble bees. Wild mustard is also blooming now in fields and it is even more attractive to bees. So if you have these blooming in your field, either spray at night, or hit the ground covers with a low rate of Roundup or other herbicide to knock back the flowers before spraying.

Purple dead nettle

Bud break. The trees are just starting to move, so we should be 2 to 3 weeks away from bud break.

The Spring Rush. There's a lot to do in the spring. This week looks like it will continue to be wet and not good weather for spraying at all. When it comes to spraying fields before bud break, it's natural to want to just get it done and ignore the weather, but many times insecticide treatments fail because of too much wind during treatment or rain right after treatment. So prioritize your fields, pick your days, and pay attention to changing weather conditions. It's better to leave a field untreated and let the predators clean up twig aphids than to waste your money and pesticides and cause problems with your neighbors by spraying when it's too windy.

Useful links. Here are some links to more information. Remember our main website has changed the web address to christmastrees.ces.ncsu.edu

• Controls Based on Treatment Window -- Spring: April through Bud Break
• Balsam Twig Aphid on Fraser Fir
• Focus on Aphid Control
• Rust Mites on Christmas Trees
• Focus on Mite Control
• Tips for Keeping Bees Safe
• Weather Conditions When Spraying

2015 Scouting Project & Early Pest Observations

Brad Edwards looking for twig aphid eggs

Because of the issues that people had in 2014 with twig aphids (BTA), and the continued issues with elongate hemlock scale (EHS), this year I'm doing an intensive scouting project. I plan on visiting 2-4 farms in the main Christmas tree counties every two weeks through the spring and summer to observe how well natural predators are working at pest control. I've been visiting potential sites the last couple of weeks to set up the project and there are a few things I've already noticed.

Twig Aphids:  I'm finding that most fields have high numbers of BTA eggs in them. Actually the fields with the lowest eggs counts are the ones that have the least amounts of pesticides last spring -- such as organically grown trees or abandoned fields. That's because the natural predators ate the aphids before they could lay any eggs. That's one thing I hope to observe this year -- what predators are most important and how early in the spring they show up.

Another thing we've observed already is that BTA eggs started to hatch the 2nd week in March which is actually earlier than normal. Typically it takes about 3 weeks for all the eggs to hatch. This may well mean that we have an early overall hatch this year. (I'll keep you posted).

For scouting, that means that by around April 10, you should be able to go out into the field and beat the foliage over a plate to see if aphids are present or not. If you sprayed last fall with a synthetic pyrethroid, this would be the time to check to see if you can get away without treating this spring. Don't look before that time as all the eggs haven't hatched yet. And also evaluate other pests such as rust mites, which leads me to the next observation.

Rust Mites: There are already a few fields with active rust mites in them. It might be a good idea to go ahead and check fields where rust mites have been a problem in the past, or fields treated last spring with a pyrethroid, to see if they are making an appearance. If rust mites are a problem, you might need to treat this spring even if twig aphids have been controlled. Also keep an eye on the weather. Rust mites love long springs. I have a feeling that this year there will be good weather for them to be a factor in many fields.

Keep Posted and Thanks! In any case, thanks to the growers who are letting me work in their fields and to the county extension agents who are helping me to make these evaluations. I plan on posting observations here so stay tuned! This work is funded in part by the North Carolina Christmas Tree Association.

Rust Mites!!!!

I really wouldn't have thought this would be a bad year for rust mites. After all, everyone was hoping that with such a hard winter, there would be fewer pests.

Looks like we were wrong!

Rust mites are cropping up in many fields. They will probably limit the number of fields that can go without an insecticide treatment this spring. But don't just assume you have to treat. Scout first! Twig aphids are now mostly hatched and even spider mites are hatching out. So scout and determine what you need to do.

From my pest management survey, I've learned that a lot of people are depending on either a bifenthrin product such as Sniper and/or dimethoate in the spring for pest control. But with rust mites so bad, neither product is probably the best choice.

Miticides such as Envidor provide a lot longer control of rust mites and spider mites both. Though more expensive, you can treat and pretty much walk away from the situation. So if mites are the only problem and you don't have twig aphids because of a fall treatment, consider just using the Envidor without mixing another product in. That will protect your natural predators.

I also think that bifenthrin is a much better product to use in the fall for Cinara aphid and twig aphid control. Then it should have much less effect on the parasitic wasp that controls the elongate hemlock scale.

The following links will provide help for mite control, twig aphid control and/or scale control.

On other thing... is flowering mustard blooming in your trees? If so, watch out for bees when you spray! Mustard seems to be the plant that brings the most bees in when it is flowering. It is far more attractive to bees than other flowers such as clover. So take special care when mustard is blooming. The following link will help with controlling pests without hurting bees.

If you have any questions, please let me know.

Twig Aphid Hatch -- Spring Pests

Twig aphids. Looked at twig aphid hatch again today. I found just over 90% of the eggs hatched (it worked out to 93%) and there were a couple of aphids that had molted. However, when Jerry Moody and I were doing beats on trees, we were still finding that they were hard to find. So if you do start scouting for twig aphids in the next few days, if you find any at all, you should probably treat in go-to-market trees.

Aphids should all be hatched out in the next few days.

Woollies. Last week we found that only a few balsam woolly adelgid eggs have been lain. This week there were whole lot more. The adults still haven't produced much wool.

Spider mites. I found my first spider mites crawling around today. Many are encysted. That means that they are molting from an immature to more mature state. When they do this, they look like they are dead. They don't move, but they are in fact alive. They are just molting and it takes awhile.

The next couple of days are supposed to be wet, but after that, start scouting trees that were treated last fall to determine if you need to treat this spring for twig aphids or for mites.

Twig Aphid Hatch

I collected shoots yesterday and examined them today. Hatch in the field I'm monitoring was at around 30%. I only saw first instar aphids -- these are the ones that have first hatched out of the egg and have not yet molted. It will be probably the last full week of April before all the twig aphids have hatched out. My advice would be to wait until late next week before scouting for twig aphids to access whether or not to treat this spring. However if you know you have to spray this spring, insecticide sprays will work any time.

Spring 2013 Pest Control

Last spring I made several posts about the effects of the warm spring on our Fraser fir pests. This spring, as you well know, is the complete opposite of last spring. Last spring we were 2-3 weeks ahead of normal. This spring we may well be 2-3 weeks behind normal.

I went out on Friday to evaluate twig aphid hatch in some untreated trees in Avery County (thanks Jerry Moody!). These trees had ice on them from the snow/sleet/freezing rain from Thursday, so it was a bit hard to evaluate twig aphids. However, the aphid eggs were very plump and ready to hatch and it appeared that a few of them had already, though I didn't see any live aphids. I estimated that about 16% of them had hatched already. Typically I see that many hatched by late March, so hatch is definitely late this year.

In most years, all twig aphids have hatched by April 15. I doubt that we have 100% twig aphid hatch by that time this year. So what does that mean for you in trying to scout and control twig aphids?

First of all, if you are scouting to determine if your fall insecticide applications have successfully controlled twig aphids this spring, you might want to wait until after the 15th. I doubt if you will see much this week in the way of twig aphids. Remember too that the aphid which hatches from the egg is the stem mother. They are all female and they reproduce without mating. At maturity they produce live young. So if you see one aphid on April 15 and your trees break bud on May 1st, that aphid has 2 weeks to mature and start reproducing. One aphid could easily turn into 15 during those two weeks. Therefore, be very cautious of scouting too early for twig aphids.

If you know you have to treat however, it's not too early to start. Any material used will last long enough to kill the aphids once they are hatched. At least one grower has already seen some rust mite activity so be sure to scout for rust mites and spider mite eggs before deciding what material to use. Also remember to protect honeybees. If the temperatures are above 50 degrees, they will be foraging in flowers.

If you are treating for twig aphids, it's a good idea to do so before cones are produced on the tree. Twig aphids will hide in the cones, protecting them from chemical spray. Once the cones have come out on trees, dimethoate is one of the few materials that will penetrate them to kill the aphids in the cones.

One word about dimethoate -- if you do have to send workers in to remove cones after treating with dimethoate during the 10 day re-entry interval, they have to wear long sleeved shirts and long pants, chemical resistant gloves and chemical resistant footwear. They don't have to wear masks.

I will keep monitoring twig aphid hatch as in years past and will keep you posted on how the spring is progressing. And if you see anything interesting when scouting let me know so I can pass that information on to others.

Strange Spring: The Continuing Saga!

This spring continues to be unique. I was in a field in Avery County at a fairly high elevation yesterday, and one in Transylvania County at a low elevation today, and bud break was about the same. Only a few trees had broken a few buds in both fields, but it looks like the trees are ready to pop. I think the cooler weather this week has slowed things down.

But don't expect the cooler weather to slow the bugs down. The twig aphids are reproducing. This typically happens right before bud break, and they are doing the same again this year. The difference is that it appears that bud break and perhaps shoot growth might take longer than normal. That means that the trees will be at their most vulnerable to twig aphid attack for a longer period of time. Also, the warm spring has allowed for good aphid survival and reproduction. It all adds up to a potentially bad year for twig aphids.

That is why I've always warned people that if you are beating the foliage and finding even a few aphids, they will reproduce and end up being a problem. Each female aphid can produce 10 to 15 live young -- making what you saw last week 10 times more this week.

Rust mites are also quite active and will remain so until temperatures really warm up.

The good news is there has also been a lot of rain, which will help the trees grow out of any twig aphid damage. The following aren't very good photos, but they illustrate my point. The first picture is of a tree with twig aphid damage in May. The second is of the same tree in July. Most of the damage has straightened back out.

Shoots actively growing show lots of needle curl...

... but the mature growth has little damage.

So don't get too concerned with twig aphids. Use your judgement. Still, it's a good idea to recheck the trees that you plan on cutting this year that are your best trees, and treat them if necessary. Dimethoate is a good choice at this point as it will penetrate the cones and any broken buds. However, remember that Dimethoate is quite toxic, and is especially a problem when bees are active (which they are now in ground covers). Consider spraying later in the day, or if you are using a mistblower, of an evening.

With as much wind as we've been having this spring, I know how hard its been to get sprays out. Just remember, that poor conditions for spraying will give poor control results. There's little need to waste time, money, and put the environment to risk by forcing a spray job under windy conditions.

Let me know if you have any questions, and good luck!

A Buggy Spring!

I revisited the field I was in last week to look again at twig aphid hatch plus going to a second field today. One field is in Mitchell County along the Parkway; the other is in a high elevation site in Avery County. The following are a few observations.

• BALSAM TWIG APHIDS are at 90% hatch. The high elevation site actually had a slightly higher twig aphid hatch! If the next week continues warm, twig aphid should all be hatched out by April 1. This only happens once every 10 years or so. Usually it takes until April 15. If using Thionex (endosulfan) or Di-Syston 15 G, wait until after April 1 to treat. All other products can now be used at any time .
• SPRUCE SPIDER MITES are hatching out. They are all at the immature stage -- no adults yet. I even saw some that were encysted -- that means they were sitting very still as if dead while they molt.
• HEMLOCK RUST MITES continue to increase. At the one field in Mitchell County, I didn't see a single rust mite in my samples taken on March 13, and now about 20% of the shoots had just a few rust mites on them. That's a pretty impressive jump!

The following are some suggestions for pest control this spring:

1. Start scouting now for twig aphids and mites. Don't wait until the middle of April. If you do it now, you will have more time to do something about a mite or aphid problem.
2. Be sure you to scout a second time before bud break to make sure something hasn't become more of an issue if you aren't planning on putting out an insecticide this spring.
3. Scouting doesn't have to be a big production either. Just going to key fields and blocks, getting out of the truck and walking to half a dozen trees should tell you all you need to know.
4. Don't just expect fall pesticides to control twig aphids -- scout to make sure they have worked.
5. Be aware of the weather. If it stays pretty, those few mites and aphids this week will be at very damaging levels by bud break. What would stop this is several days in a row of wet weather or a return of winter for a few days.
6. Remember that Dimethoate will only give a knock-down of mites. If the weather stays favorable (which so far it has) those mites will come back from the eggs. However if all the spider mite eggs are hatched and they haven't yet started to lay more eggs, then a single treatment of Dimethoate should work well. This also means that Apollo and Savey, products that only work on eggs and immatures, will not need to be mixed with another miticide such as Dimethoate to work. But this will only be true for about another week. For a list of miticides and how they work see Christmas Tree Note # 29: Spruce Spider Mite on Fraser Fir. 
7. Remember to use up your Thionex before July 31 of this year. Wait until April 1 before using it if you want twig aphid control.

If you have any questions, email me at jill_sidebottom@ncsu.edu

Good luck this buggy spring!

Spring Bugs

SUMMARY: With the spring weather, many pests and predators are becoming active. Twig aphids are already starting to hatch which is earlier than most years. Rust mites are very active. Cinara aphid populations may be crashing from earlier this year with increased activity from lady bugs. Be sure to be in your trees scouting so that you'll know if you need to treat and can choose the best materials for control. For more details, see below!

Spring has sprung as they say and bugs are no exception. Today I visited two fields in Mitchell County with Jeff Vance and found a lot of activity.

Cinara aphids. In one field, we've been following a heavy incidence of Cinara aphids since the first of the year. Most of these aphids are dead already from natural causes. We saw several Harmonia lady beetles feeding on them. We also found some white sap or honeydew on some of the needles. I tasted it and it was definitely sweet. There's a lot of sooty mold too on the trunks and branches --  parting gift from these pests! Below are some photos.

Most of the aphids are dead, but there is one in the middle right hand that is still alive.

White sap or honeydew on the needles where Cinara aphids have been feeding.

Harmonia lady beetle.

I think this lady beetle is infected with a fungus.

Balsam twig aphids. The aphids have started to hatch already. They are about a week to 10 days earlier than normal. I would estimate that 25% of the eggs have hatched already. I did see a dead aphid and an egg that looked like it might be dead -- black inside. A lot of rain will be hard on the aphids and some will die. A cold snap will kill many too if we have one.

However, I am afraid that since the spring is so early and it is staying warm, that twig aphids may be bad this year. Be sure to scout in fields where you treated last fall with bifenthrin products such as Talstar to make sure that you have good enough control. The warmer it is and the longer time from egg hatch to bud break, the longer the aphids will have to mature and reproduce. This may be the year that fall twig aphid controls fail us, so be sure to keep looking!

If you are treating this spring for twig aphids, you can start treatments any time . The only exceptions are Thionex and Di-Syston. With these products you need to wait until all the twig aphids have hatched, but that may be within two weeks!

Hemlock rust mites. Another pest that really likes the early spring are hemlock rust mites. In one field I was in today, the rust mite population was almost at treatment threshold. It was at 60% incidence and one shoot had at least 8 mites per needle.

Rust mites like spring and since we are having a pretty one, they will most likely be bad. They haven't been the last few years, so don't be caught off guard. Be sure to scout fields and treat for them if necessary. What are the best materials for HRM control? Horticultural oil, Envidor, and Sanmite are three of our best products. Dimethoate knocks rust mite problems down, but they will rebound. In fields with rust mites, be careful about using synthetic pyrethroids (Asana, Astro, Talstar, Wisdom, and Sniper) as these products will make rust mites worse. They may also make elongate hemlock scales worse, so only use them when necessary in the spring, or better yet, save their use until fall.

Spruce spider mites. I saw quite a few spider mite eggs today, but no mites that are hatched out yet. I do know of some folks that have seen mites crawling. If the weather continues warm, I'm sure it won't be long until they are active.

Twice stabbed lady beetle. We also found a couple of twice stabbed lady beetles active in trees that have elongate hemlock scales. Here is a photo.

From this angle you can only see one of the red spots.
Still not a bad shot considering I was using my cell phone!

What's the take home lesson with all of this? It's time to scout, of course!! Be sure to get out in your trees over the next couple of weeks to see what's active. And pay careful attention to rust mites.

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.

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!

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.

Pests Getting Started This Spring

Hasn't the weather been fun the last few weeks? Talk about a yo-yo! That's hard on us, and it's hard on bugs too. Warm weather allows them to mature and reproduce quicker and survive better. Cold and wet has the opposite effect. So what are people seeing now?

BTA

I haven't been out in the field yet, but Doug Hundley has reported seeing three instars of twig aphids. If you will recall, these aphids begin hatching from their eggs in mid to late March. They molt four times before becoming an adult which can produce more live young.  So what does that mean? What's an instar?

Remember that insects don't grow like mammals do. I have a new puppy, and every few days I think -- Gosh he seems bigger. Insects don't do that. They grow in stages since they have to shed their skin (molt) to get bigger. Different species of insects mature differently. Twig aphids have four molts so there are four instars. If Doug was seeing three different sizes of aphids, that means that the twig aphids are hatching and growing and fairly far along with their life cycle. But also remember that twig aphids hatch over a several week period. The oldest aphids he saw were probably the first ones to hatch. Usually it takes until April 15 for all the aphids to hatch out. I would think that with our periods of snow and cold which seem to come every week, that it will take that long for the twig aphids to completely hatch. However, if you are using any insecticide except for granular Di-Syston or Thionex, any materials you spray now will work fine. It will last long enough. These two work best when applied after all the eggs have hatched.

So is it best to wait later in April to early May to treat for twig aphids? Not necessarily. First of all, the longer you wait, the more you at the mercy of the weather. The other factor are cones. Cones can reduce the effectiveness of insecticide applications. The bracts on the cones protect the aphids. When the cones are very small, the aphids can't get under these bracts. So if you have a lot of cones and are spraying for twig aphids, it would be better to treat sooner than later. Otherwise you will have to remove all the cones. Of course, you'll probably do that anyway.

Dimethoate has proven effective even when the cones are more mature, so if you get caught with bigger cones, consider switching to that material.

HRM

Brad Edwards reported seeing some rust mite activity recently. The presence of rust mites in the spring may affect what pesticides you want to use. If you treated in the fall with Talstar and don't have and twig aphids this spring, you might still need to spray if you have rust mites. And if you were going to spray anyway, the presence of rust mites may make you want to add a miticide. Remember that Talstar, Apollo, and Savey don't have any activity against rust mites. They only control spider mites. Dimethoate controls rust mites but not the eggs. If this materials is used -- especially early in April -- you might have to reapply come May. Sanmite and Envidor control all stages of both rust mites and spider mites, making them worth the extra cost.

So how do you know if you controlled your twig aphids last fall or if you have rust mites? That's right. You need to scout!

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.

End of May Explosions

Rust Mites. Bryan Davis has seen in a few fields a real upsurge of rust mites in the last few weeks. With the cooler weather, and especially cool nights, rust mites are remaining active. Some of the fields that only had a few rust mites in them a month ago are getting damage now. So if you haven't been in your trees lately and the field is prone to rust mites, it might be a good idea to check and see if rust mite numbers have exploded.

Should these fields be treated now? That should be decided on an individual case basis. The weather should be warming up soon, but as long as the nights stay cool, rust mites will continue to be active. Only treat now if mite numbers and damage truly warrant it.

Twig Aphids.  Also, there have been a few fields that weren't treated for twig aphids this spring because of fall treatments that twig aphid numbers seemed to explode in. A month ago, there weren't any twig aphids, but now there is some damage.

This spring allowed the few aphids that did survive a chance to quickly reproduce. However, with all the wet weather, the trees are growing so well that much of that needle curl will be grown out of. So it is nothing to treat for, but only to be aware of.

Twig Aphids Reproducing

Just wanted to let everyone know that I examined some shoots under the microscope today and found evidence that the twig aphids have matured enough to being reproducing. Remember that the form that hatches from the egg is called the stem mother. At maturity she lays live young. That is taking place now.

With this warm dry spring, twig aphids are surviving well and maturing quickly. There is a potential for damaging numbers to build up quickly now.

Twig Aphids

SUMMARY: Twig aphid hatch is at about 86%.

Jerry Moody and I applied Movento with different adjuvants today. Remember that Movonto is the systemic that needs a good penetrant to get into the foliage. The problem is that several we used last year caused needle burn. Also, we didn't get great twig aphid control because we didn't put it out early enough.

Well, we got it out early enough this year! We tried Movento at the full 10 oz/acre rate either alone or with the following adjuvants: horticultural oil, Eco-Tec, ammonium sulfate, NIS (80/20), Liberate, or Phase.

I checked the twig aphid population at the field site, and there were plenty of aphids -- approximately 1.4 eggs per shoot. I estimated that there was about 86% hatch. There are several 2nd instar aphids. So, you can start scouting for twig aphids now, and certainly by next Monday, you can easily scout for twig aphids.

I think we put in a good study. I'll let you know the results come mid-May.

End of March Assessments

I've had the opportunity to walk through several Christmas tree fields the last couple of weeks. Here are some of my observations.

BALSAM TWIG APHIDS: I'm still not seeing many fields that have high twig aphid numbers. I finally found a couple that did, but mostly there aren't many aphid eggs. Bryan and I found our first live twig aphid on March 30! It was tiny -- just a fist instar. The weather during April will determine how bad twig aphids end up being. Now we're having warm, dry weather which will allow the aphids to quickly hatch, mature, and start to reproduce -- laying live young. If this kind of weather keeps up, those few aphid eggs will turn into plenty of aphids to curl needles by bud break.

We were in one field that had been treated with Talstar in the fall, that actually had a dead aphid sticking out of the aphid egg. But it's still a bit early to be evaluating how these fall aphid treatments are working. Wait until April 15, and then it should be easy to beat aphids out of trees if they are present.

However, if you didn't treat in the fall, and you need to control twig aphids, don't wait until the 15th unless you are using either Di-Syston or Thionex. All other materials including Asana, Talstar (Wisdom), and Dimethoate can be applied now.

BALSAM WOOLLY ADELGID: I visited another field yesterday where several trees were showing symptoms of woollies (flat tops, swollen buds, stiff trunks), but it was extremely hard to find any live woolly on the trees. What we did find were on the buds, and we had to look at lots of buds before we found them. These trees had been completely untreated in 2009. Therefore, I think we're seeing quite a bit of winter kill of BWA, but don't assume they are all killed out. Fields with symptoms of woollies should still be treated for them.

SPRUCE SPIDER MITES: I have yet to find a field with more than just a few spider mite eggs this spring. I'm sure they are out there, but for now, I don't think there are many growers that will have to worry about this pest.

HEMLOCK RUST MITES: Rust mites are really active this spring -- much more so than in the last couple of years. We walked through several fields last week that had been treated in July or August with Dimethoate + Asana to control elongate hemlock scale. This is a combination that should create rust mite problems the following spring, but of the four fields we visited, only one had rust mites. The other fields had virtually no mites.

We walked through another farm this week that had been treated with Talstar in October. It was a very large farm that rambled up and over a ridge, dropping down to the river. On the ridge top, the rust mites were nearing treatment threshold. In other areas of the farm, there weren't any.

So what's a grower to do??? SCOUT!!!! You can find the blocks that need rust mite controls and target only those for treatment. It doesn't take a lot of time to scout. A field of several acres can be evaluated in just 30 minutes. That's worth knowing where you need and don't need rust mite control.

Envidor will provide longer lasting control than just dimethoate. After all, it's a long time until summer. Spring's barely started.

Rust Mites & Twig Aphids

Just wanted to let folks know that I was in a field yesterday that had quite a few rust mites. It was up to our treatment threshold of 80% incidence and at least 8 mites per needle on one shoot. The most I saw was 25 mites on a single needle. So, it's not too early to get out there and look for rust mites.

I haven't seen my first twig aphid hatched out yet, but I'm sure they have started to hatch. Really, there aren't many fields that have much twig aphid in them. You might have to pull of 10 to 15 shoots before you find an aphid egg. Don't be fooled, though. That slight number is still enough to cause damage if we get a warm, dry spring. Of course, we haven't so far, so we might do well with twig aphids this year.

March Madness

Well. Not quite. I thought it might get people's attention. Of course, people do get a bit mad in the spring. "Mad as a March hare," the English used to say. People are just now realizing what all they have to do this spring -- at least I know I am.

Just wanted to share a few observations I and others have been making this spring.

BALSAM TWIG APHIDS: I haven't seen any hatched yet, but the eggs are getting plump like they are ready to hatch. However, I haven't found any fields so far with a high incidence of twig aphid eggs. You might pull off 10 shoots before you find an egg. I guess last spring it stayed so wet that the aphids didn't reproduce well. Remember, though, that even these low numbers can result in damaging levels of twig aphids if the spring is warm and dry, as the aphids reproduce so quickly.

VOLES: Both Bryan Davis and Doug Hundley are seeing greater than normal vole activity. With all the snow cover, it only makes sense.

Bryan sent the following in a March 17 email, "I have seen a tremendous amount of signs of rodent tunneling under the snow. During the winter when the snow melted on some fields signs were visible and as I've been out over the last two weeks I've thought this is the most sign I've ever seen. I recall seeing some signs of rodents last fall where we were spraying deer repellent and as I've returned to these farms there is more signs of rodent activity. The tracks I'm seeing don't seem to bee tunneling in the soil, but on top of the ground. I haven't seen any damage such as girdling or dead trees in these fields yet. I'm going back to one site today that has had a lot of activity and I'll look closer for signs of damage. As far as control, I had a grower asking about this last fall and I checked with Scott Henson about what they carry at CPS and they had rodenticides, but they came in large volumes. Hopefully now the hawks, foxes and cats can work on these pests."


I've only found voles damaging Fraser fir once -- and in that field they completely severed the trunks of small trees. The poor little trees looked like pencils stuck in the ground. Rodent control on that farm involved controlling the thick grass in the field, allowing the hawks to work it. Like Bryan says, the natural predators should take care of things.


RUST MITES: Bryan and I found some rust mites getting started over the last couple of weeks, but numbers were still very low.


OIL TRIAL FACTS AND FIGURES: Bryan sprayed some trees with the new Saf-T-Side oil last Friday. We used a backpack mistblower and a 2% rate. I'll try to get back there next week and see what the eggs look like. He was using about 100 gallons of water per acre to get good coverage. That is probably more than most growers could use, putting it out 3 1/2 gallons at a time. Another grower we talked to figured he was applying about 8 backpacks per acre for around 28 GPA.

That grower burned some trees with oil last year using his high pressure sprayer. All the needles fell off of some trees. The buds for 2009 weren't touched, and so all that's left is 2009 growth. Here is a picture of one of those trees. Hopefully this new oil will be easier for growers to use and won't cause burn.


Oil isn't cheap. If you are using the regular oils which are about $14 a gallon -- a 2% solution and 300 GPA comes out to $84 per acre. When Bryan sprayed last year, he used up almost a case of oil (5 gallons) on 1,000 trees which cost more than $100 per acre. But, Bryan hopes to market these trees as "pesticide-free" this fall which should give him an advantage over conventionally grown trees.


If anyone sees any interesting pest problems, let me know so I can share them with everyone.