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.

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.

Post Harvest Pests

Heard about my first post-harvest pests today. Cinara aphids. Anyway, here are links to information about these pests.

1. Grower information on Cinaras.
2. Information for the retail lot operator.
3. Retail lot information in pdf format.
4. Photos of Cinara aphids.
5. Consumer education information on post harvest pests including Cinaras, praying mantids, and spider mites.

If you need me to speak with retailers or consumers about this issue, email me at: jill_sidebottom@ncsu.edu

Jeff Vance is holding a bottle of insecticidal soap.
This works well against aphids and is completely safe
around children and pets. It does have a bit of an odor.
You can buy this pre-mixed in high end garden centers.

This is a photo I received from a consumer a few years ago.
Surprisingly it's never hard to ID Cinara aphids from the  strange photos I receive.

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.

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.

MITES!!!

I'm surprised how many spruce spider mites I'm seeing this spring, considering how wet it's been. I have been in several fields where individual trees were absolutely cover in mites.

This terminal is covered up in spider mites and their eggs. There is even some webbing between the needles which is where spider mites got their name.

This shot shows my fingers after handling the mite covered terminal. This is the color of squished mites!

These trees were at the site of our organic study. I think I will treat them all sometime in the next few weeks. What's complicating this is that the new growth is out. I'm afraid I'll burn them which is why I'm going to hold off a few weeks.

The final shot I'm posting today shows the difference in the ground covers between the organically grown trees, which are full of grass, and the "late" organic trees that are still being grown conventionally with Roundup use. We will switch to organic production the last three years before sale.

The organic is in the background, and that's where Brad's mowing. In the foreground are the "late" organic, which haven't been treated yet with Roundup. There were areas of the field where the clover was keeping out any weed problems. There appears to be much more biodiversity with the use of Roundup. Hopefully this summer I can get some data along these lines. But for right now, a picture is worth a thousand words!

Mites on the Move

Finally got out in some trees yesterday, and didn't have any problems finding mites -- both rust mites and spider mites. The spider mites are just now starting to hatch out and move around. Taking a quick check on mites in your trees will help you decide what pesticides to apply this spring, or even if you can skip a treatment.

The March 10, 2010 post "Spring Insecticides for Pest Control" gives a good summary of materials you can use this spring. The following image reviews how well some of the common materials control different pests. The big X means it works really well. The smaller x means it only works somewhat and might need an added material to give really good control.

Other miticides that you might use include the following:

1. Sanmite which like Envidor controls all stages of both spruce spider mite and hemlock rust mite
2. Savey which controls the eggs and immatures of spider mites -- no activity against rust mites
3. Apollo which has the same type control as Savey
4. Floramite which should control all stages of spider mites

It's always good to rotate materials, especially with pests like mites that have multiple generations each year.

Remember that Thionex will no longer be available for sale after July 2011, and you can't use it after July 2012, so don't purchase now more than you can use.

For a listing of pesticides labeled for Christmas trees and links to the labels and MSDS sheets, view our new pesticide page. 

For information about farm and pesticide safety, go to our new safety page.

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.

Role of Apollo

Several folks have been talking about treating this spring with Apollo plus Dimethoate. Apollo is a miticide with similar activity to Savey. Those Apollo plus Dimethoate should give good control of twig aphids and spider mites, but only fair control of rust mites. After all Apollo, though an ovicide, has no activity against rust mites, just as Savey doesn't.

The kicker is, there are almost no spider mites anywhere. I've worked  tree fields for several weeks, Bryan Davis has, and several other agents. Fields with spider mites are few and far between. I think I've seen a dozen spider mites eggs total in 3 weeks of scouting.

Rust mites, however, are being found frequently. A few fields have high rust mite numbers. Other just have maybe a mite per shoot. (Remember that the treatment threshold is 80% incidence and at least 8 mites per needle).

The mix of Apollo + Dimethoate will knock rust mites down (due to the Dimethoate), but since it is so early in the season, the mites may rebound. That is why in a situation where rust mites are plentiful now, Envidor is the better choice. It controls both spider mites and rust mites. Envidor plus Dimethoate should give excellent and full season control of twig aphids, rust mites and spider mites.

Scouting will determine which blocks should have the Envidor added, and which don't, as rust mites are not a problem in every farm or even on every block on a farm. Don't assume that just because you used either Asana or Talstar last fall that rust mites are a problem. They aren't. You don't know until you go out and look.

And scouting doesn't have to take a lot of time. When I go out with the county agent or technician, it always takes longer because we're talking about control options, showing the grower different pests and the like. But if I was just going out there to scout, it wouldn't take me long at all.

Envidor is only labeled to be applied once per year (as is Savey and I think Apollo as well). This is to reduce the likelihood of resistance. But chances are, spider mites won't develop and become a problem if you have good ground covers. Even during droughty years, we've seen very few farms with bad spider mites in recent years. Once again, a quick scout through should be able to identify problem sites.

So scout. Then chose what you need based on those scouting results.

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.

Spring Insecticides for Pest Control

The weather so far this year has put many people behind already. Many growers treated last fall with insecticides and are hoping to get twig aphid control this spring from those fall sprays. In fact, in talking with county agents, we estimated that at least 4,000 acres of Fraser fir Christmas trees were treated in the fall and will hopefully skip a twig aphid treatment.

But what options do growers have that didn't treat in the fall? I'll try and list them all below. If anyone has any other's they'd like to share, email me and I'll add them. As I go through different materials, I'll be using abbreviations for pests with BWA=balsam woolly adelgid, BTA=balsam twig aphid, SSM=spruce spider mite, HRM=hemlock rust mite, and EHS=elongate hemlock scale.

The first consideration is do you even need to treat for twig aphids? If you aren't cutting out of the trees this year or next, you don't need to control BTA. You should walk through your trees to make sure mites aren't a problem, but you can probably skip treatments.

A second consider is what have you used in the past for insect control. It's important to rotate materials from different chemical families. In other words, products like Asana and Talstar are both synthetic pyrethroids and so have similar modes of action. Think about what you used in past years, and try to use other products this year. For a complete listing of all the chemical families, go to the IRAC Mode of Action Classification.

Another consideration is that it doesn't all have to be done in the spring. You can get control of pests in the summer and fall when you have more time and can pick better weather conditions. At the end of this post, I have some possibilities for when to treat if you have all the major pests.

And just a few more words of wisdom: Remember that all pesticides are dangerous to something -- whether the bees in your trees, or the stream insects below your field, or the man putting it out -- so read and follow the label. Labels can change every year, so be sure to read them each spring. Also, be considerate of your neighbors. Remember that getting good coverage is just as important as what material(s) you choose to use. Also remember that if the wind is blowing, or if it rains before the spray has dried, you are wasting your time and money. Be sure to scout after using any of these products to make sure they have worked.

Anyway, here is a list of products, their rates, different mixes and what they will control.

1. Horticultural oil. Use a highly refined oil -- 92% unsulfonated residues or better -- at the full 2% solution -- that is 2 gallons in 100 gallons of water. When applied in March with a high pressure sprayer, it will control BTA and HRM very well, and will help reduce SSM, BWA, and even EHS. Be sure to get good agitation so the oil and water don't separate. We're going to be looking closer at Saf-T-Side oil which won't separate in water to see how well that works.
2. Asana. Can be used anytime from February through bud break to control BTA (5 oz/100 gallons) and BWA (10 oz/100 gallons). Add a miticide if mites are present. Will also knockdown EHS. However, there is also a potential to create problems with HRM and SSM when using Asana -- even the following spring. If BWA control can wait until fall, rust mite problems can be avoided when using this product. 
3. Dimethoate. Use at full rate of 24 oz/acre. From last week of March through bud break will control BTA and knock-down EHS, HRM and SSM.
4. Dimethaote + Savey -- BTA plus SSM control (the Savey controls the mite eggs). Also Apollo can be used in this manner. Still will only knockdown EHS and HRM.
5. Di-Syston 15 G -- There might be some folks who are still using this. It will control BTA and SSM and possibly a brief knockdown HRM. Be sure to apply when there is no wind and scout after treatment to make sure it worked.
6. Talstar. Use at full rate of 40 oz/acre. Will give BTA and BWA control from February through bud break. Should also give control of SSM. (Though Talstar doesn't have any activity against mite eggs, it should last long enough to kill the mites that hatch from the eggs). Doesn't control HRM or EHS well.
7. Talstar + Dimethoate -- BTA, BWA, SSM and knockdown of HRM and EHS.
8. Thionex. Use at full rate of 2/3rds of a quart (about 21 ounces) for BWA control. Wait until mid April through bud break to get BTA control as well. (It just seems that BTA control is more reliable with Thionex if you wait until all the aphids have hatched out). Add a miticide if mites are present. Has no activity against EHS.
9. Thionex + Dimethoate -- BTA, BWA control and EHS, SSM and HRM knockdown. Some folks have been using this mix without scouting first, thinking that it will control about every pest. But control of mites and scales will only be fair.
10. Envidor. Use at 18 oz/acre for HRM and 25 oz/acre for SSM control. Therefore, if you add Envidor to any of these products listed above, you will also control these mites. Will it keep the mites from developing later in the year or next year? Probably not. I would prefer seeing people keep on scouting and apply when needed -- not as a preventative.
11. Dimethoate + Asana -- Use dimethoate at rate of 16 oz/100 gallons and Asana at the highest rate of 10 oz/100 gallons. Will control BTA, BWA, EHS and knockdown SSM and HRM. Wait as close to bud break as possible to get the most out of EHS control.This mix would give better control of EHS in summer.
12. Dimethoate + Prev-Am Use Prev-Am at 0.4% solution (50 oz/100 gallons). Will control BTA, EHS and knock-down of SSM and HRM. Prev-Am has burned trees at higher rates, so be careful, but this mix sure smells better than straight dimethoate!
13. Lorsban -- will control BTA and knockdown SSM and HRM (?). Will also control BWA in March -- but not once woollies start laying eggs. Will control EHS??? We're still looking at this, but it did a great job last October. We've seen some issues with Lorsban burning foliage, so be careful.

So, what would I use if I had everything -- BWA, BTA, SSM, HRM, and EHS? I would probably either use Asana + Dimethoate and continue scouting for the mites to see it they rebound, treating with Envidor if they do, or go ahead and use Asana + Dimethoate + Envidor (which would be rather pricey). Or, I might wait to control my BWA and EHS in the summer with Dimethoate + Asana, and just use dimethoate in the spring -- and scout for mites later on. If you wait until August or September, you should pick up BTA control for the following year. Or I might use oil in March every year to control all these pests.