How to treat for crapemyrtle bark scale
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- Опубліковано 28 сер 2018
- Crapemyrtle is one of the few trees that blooms throughout most of the summer. It has become a popular landscape plant for that reason and because it is relatively pest-free. Not anymore. A new exotic pest, called the crapemyrtle bark scale, drips honeydew, turns bark black, and reduces blooming. This video shows homeowners how to treat the scale and make their trees look good again.
For gardeners concerned with the impact of these pesticides on bees and other pollinators, such concerns have been weighed before publishing these recommendations. Our research team has looked at soap washes and horticultural oil treatments, neither of which provided any significant control in repeated trials.
The neonicotinoid insecticide recommended in this video has recently been shown capable of reaching pollen of crapemyrtle trees (in small amounts) through the roots and vascular system of the tree (crapemyrtles do not produce nectar). This is of concern, though crapemyrtles are not highly attractive to bees when other pollen sources are available.
At the time of production of this video, we believed that the impact of the relatively few trees treated with imidacloprid would likely have a minimal impact on honey bee colonies and other solitary bees. Researchers continue to look for alternatives to these products until and unless definitive evidence shows these treatments pose significant harm to your landscape's beneficial insects.
If you find that handwashing or spraying with water and/or soaps provides sufficient control to keep your trees sufficiently attractive, we applaud you. Anytime pest control can be accomplished without resorting to a long-lived chemical, it is a good thing. - Домашні улюбленці та дикі тварини
This was so helpful! The pace and step-by-step clarity was perfect. I was worried about my crape myrtles dying, but now I feel confident in treating them.
Thank you so much! I just washed my tree with soap and water and it already looks 80% better. I'll be putting down the exact same pesticide you used in this video as there are no blooms on my tree yet, just some new growth. I MAY be able to save this tree 😊
Excellent job. Very helpful
I just cut them down to 1' off the ground because some experts say that the scale can infect other plants like boxwoods and privet. To bad I had to mess up these beautiful trees.
Good information. Thanks.
Thank you. Very helpful.
Thank you so much for your informative video. It is excellent !! To tell you I am grateful would be an understatement!!
Thanks so much for the complete explanation of treatment. Happy this is here. When I first started to see bark scale, there hadn’t been enough research.
Thank you for the video, very informative 👌🏼
Thank you so much 😊
thank you
Very helpful!! Thank you. I had no idea what happened to my precious crepe myrtle. Very informative, easy to follow and understand. And what's so beautiful...is my crepe myrtle hasn't bloomed yet for the season. Right on time!!!
Thank you
Thanks.
Thank you!!! Very informative.
I have one crate myrtle and I’m sure my neighbors think I’m nuts the past couple years watching me scrub my tree :)
I did it. Scrubbing with steel brush works. I saved a large tree almost overnight.
Dude I just did this and I also felt crazy but anything for our trees :)
I just took a hose and put it on jet and blasted the bugs off mine. Gonna treat it with insecticide now.
Can you do a close up on the products? I am a visual learner. Thanks!
I use a pressure washer.
Hi Dr. Merchant - I happened upon this very helpful video a few years after you made it. When is the right time to apply in the spring? Should I wait until I see new growth or is it ok to apply in early spring which is now in Houston.
Where do you try the line on what branches you need to wash? Should you just do the main trunks or everywhere you see the scale?
So i can use dawn on dishes, baby chickens and trees now.
So....my trees are well established and fairly large... each tree would need...2 bottles? Dang. Thank you for the video!
What about the other stuff? Do you put both to treat the tree?
Great info. It strikes me the high cost of treating your trees if all must be treated once the issue is spotted. You just used a whole bottle of systemic on one tree ($15-20) but have many other trees, so do they get this treatment now as well or do you wait until there are disease signs showing up ?
Can I use Sevin?
I remove scale with the "jet" setting on my hose-end sprayer. It has to be repeated a few times in the summer, but at least it won't kill bees and other pollinators. If I have to resort to some alcohol/soap/tea tree oil concoction, I'll do that, but I'm not touching this chemical crap. I learned my lesson with RoundUp.
Great video, very informative! The only video I could find on how to treat bark scale on crapemyrtles.....
Question - looking at my crapemyrtle tree, the bottom is bare, and the bark is completely spotted with white bark scale. The top part of the tree, with the foliage, it mainly only has scales at the base of the leaf stem/bark throughout the entire tree. I live in Oklahoma, it currently is July, with unusually hot temps, in the 100's currently. It bloomed beautifully in May/June.....at least half of the blooms have fallen off at this point.....
I know you mentioned to treat in the Spring/Fall, when there are no blooms, but the scales are ridiculous, and I don't want to lose my tree to these insects!
Right now, most of the blooms have fallen, do you think I could do a treatment right now before it reblooms or should I just wait until Fall when it stops blooming?
Thank you kindly! 😊
While treatment right now would likely be effective, the labels on soil drench treatments generally prohibit application to trees in bloom. This is to avoid harming pollinator bees. If you want to do something, you'll have to limit yourself to washing the tree down with a soft brush and bucket of soapy water. The good news is that predatory insects usually join the battle against your scales in mid- to late summer. And they are less affected by the soapy water scrub than by the injected insecticides.
Have you, or your team, considered Neem Oil? This is a natural systemic insecticide. Let us know what your findings are.
Question... my crate myrtle had black scale. I thought we fixed it. Came back from vacation and now I have a lot of knots on the trunk of these mature crates. HELP? How do I get rid of the knots? Can these trees be saved?
If this Bayer systemic insecticide stays within the tree for up to 2 years, and if the insecticide kills bees, then why say to put it around the tree early in the season or after the tree stops blooming. If it stays in the tree that long then would it not affect next year's blooms and still kill the bees? Or am I misunderstanding something?
Very astute. The regulations are not exactly scientific in that regard. Fortunately, crapemyrtle is not a highly attractive tree to bees. It is wind pollinated and therefore lacks the highly attractive nectaries that bees visit for nutrition. New research suggests that some insecticide does appear to make it to the pollen, unfortunately. We are still researching whether the quantities are biologically significant, and whether bees will gather enough CM pollen to harm a colony. If we find that they do, it may affect the label instructions in the future. Pest control is sometimes balancing risks of the application versus the benefits. We continue to look for ecologically safer options, but it is a process.
I have black scale on my new myrtle (less than 2 years old), so cleaning the 1/4 in" trucks is not viable yet. Would the insecticide work on it own without cleaning the bark, longer healing time?
Can I use one bottle on my two tree
Truly appreciate the play by play. Might have seemed silly to film the scrubbing, but it was needed for this stubborn brain to actually get a visual. Thank you for that!
I do have questions...does the soap need to be rinsed? And I assume since you said not to apply after a rain, it would be prudent not to apply the insecticide immediately following the scrubbing.
My question is posting in the month of March and application will be in days. In my region, there is no sign of spring growth as of yet. Also we trim the tree back in the winter so currently all that is there is the sculptural trunk. There are no limbs-they will sprout from the trunks to make a tree (not a bush). It is currently only 6' in height, very matured THICK group of trunks. 2 times wider in diameter than your example. Once it begins to grow the tree will reach 13 to 15' in height. Do I use the 6' pruned trunk measure for liquid measure in treatment? Thank you! ~ this black soot scale stuff, has turned my Crepey Myrtle to that of a CREEPY Myrtle.👽
Thanks for your comments and questions. Soap does not need to be rinsed. I don't believe it should matter whether you wait or not, unless you were waterlogging the ground with your soapy water, though many gardeners like to do the soap wash earlier in the season, before leaves have emerged (some soaps can burn tender new foliage), and wait until leaves emerge to apply the insecticide. That's the time we think is optimal for application. For oddball trees like yours, with big trunks and little canopy, you might need to use the instructions based on trunk diameter.
@@observr1 Oh thank you! If you don't mind, since my tree is a wee bit sickly, I am going to leave that "odd ball" moniker and comment between the two of us. It needs positive affirmation and that ain't it. Will measure the waist of the trunk per your advice. The leaf emergence application of treatment sounds logical. Wouldn't have thought of that one on my own. THANKS! And thank you very much for your time!
Can I use twice a year or not ?
Great video! Do what he says. Don't apply in bloom.
I need the name off the insecticide
I just noticed we have 2 trees with a good amount of the white stuff on the limbs/branches and the leaves are turning a yellowish brownish color. Can I treat the tree now or do I have to wait until late winter? Would a neem treatment work?
These are insects that reproduce at the fastest rate. They flourished during the spring and fall.
Hi Michael , can I use this method on my grape fruit and guvava plant ?
Probably not. Read the label. Usually these systemics are not labeled for fruit trees.
What if you have a few 2 feet shrubs around a 12 foot tree?
Nearby shrubs may indeed absorb some of the insecticide, but you should still be able to get control if you apply to the root zone of the crapemyrtle.
I have white specks on the upper most branches. I listened to the video twice and he stated to wash only the trunk with soap and water. Should I also wash the smaller branches at the top of the tree that also appear infested? If someone could get back, that would be great. Thank you.
For most people, washing upper branches and small twigs is not practical. Not to mention physically scrubbing small branches hard enough to dislodge scale is difficult. The washing process will not rid your tree of scales anyway but is primarily for aesthetics--making the trunks look better. While we don't recommend pruning large branches in the winter (a practice horticulturalists often refer to as "crape murder"), taking some time to prune last year's twigs with old seed heads and/or signs of scale would probably be faster and more effective at removing some scale than taking a toothbrush to those smaller branches. Restrict your pruning to branches pencil thickness or smaller and you'll keep the form of your tree and have it look nice.
When washing the tree, do we need to do anything with the removed white insects/larvae pouches? Is it okay if they get on the ground? Do we need to remove them by hand and kill or is just washing the bark with brush enough to scrape it off sufficient?
No. Soap is pretty good at killing eggs and most of what you see is old scale covers, which are not alive. Keep in mind though, that soap scrubs are more for aesthetics than for killing the scales. We have never gotten very good scale suppression with washing--they usually come back if conditions are good for them.
What if your crape myrtle is in a shrub bed unlike the ones you are showing in the video? Mine is surrounded by azaleas, liriope, and flowers. How does this change the treatment and dousing of the ground?
Sounds like you have a pretty yard. I would still treat as he did in the video. All the plants would probably benefit from the treatment.
The label does not require a change in dose. Although you are correct, these plants may also take up some of the insecticide, the small amounts involved should not affect the treatment. Many of the trees we treat in our research are similarly surrounded by ground cover.
Is this safe for my 9 month puppy?
What time frame would you expect to see results in?
Because the scale insect don't slough off immediately after dying, and because the black sooty mold sticks around awhile, you probably won't see dramatic results on your tree; but scale death is actually pretty fast--a week or two in most cases. You can speed up the improvement in the looks of your tree by washing the trunk with soapy water and a soft bristled brush.
@@observr1 that's great news! Thanks for following up, I appreciate it
Great video. How about one to shoo cicadas. 😇
Is this safe for my 9 month old puppy?
Imidacloprid is an insecticide and like any insecticide can be harmful with high enough exposure. But to give some context, imidacloprid is used as an on-animal treatment (Advantage) for flea and tick control. Keep the puppy away from the treated soil till it is dry and you and puppy should be fine. Mulch with clean mulch after treatment if you want to reduce any potential exposure even more.
Why not use horticultural or dormant oil?
This question is dope. It is so much better then the expensive ass chemicals I have tried in the past. But you are limited by the temps if you are going to spray it. For instance it’s active ingredient is mineral oil, so plants that get dripped on after that treatment may be cooked. I had this happen in July after not having success with imadiclorpid and Zylam
Oh also it works by smothering the insects so they cannot breathe. The other two insecticides are systemic and the plant will absorb this chemical and give protection for a few more weeks to get the new that just weren’t coated previously. You can also power wash some of them off.
What are organic options to treat this? These bugs have spread from my crape myrtles to my vegetables and onto my flower bed, throughout the entire yard. Even if I pull all the infested plants and burn them, the damn things seem to live in the soil waiting for me to plant again. They are literally sucking the life out of every living thing on my property.
These insects are highly host specific, and are only known to feed on crapemyrtle and American beautyberry in the US. If you have problems with insects on other plants, they are not related to what you are seeing on your crapes. Organic options are limited to washing trunks with soapy water and a soft-bristled brush, and waiting for ladybeetles to move in.
Is there anything i can use while my Crape Myrtle is in bloom?
We have looked at contact insecticides like soaps and oils, but these products do not seem to provide any significant control. There are some other foliar applied insecticides (buprofezine, pyriproxyfen and Flupyradifurone) that appear to be effective and can be used safely during bloom, however these are not readily available to consumers. You can try scrubbing trees with soapy water solution and just wait for the lady beetles to come to the rescue. Next spring, then, use one of the soil applied products March to early May.
Would interviewing you for my UA-cam channel be out of the question ?
Thanks for your request, but I'm now retired. You should check with the new entomologist, Bryant McDowell at the AgriLife Extension office dallas.tamu.edu/about/team/
I'm rather surprised to see TAMU promoting systemic insecticides considering the high risk to pollinators and potential bioaccumulation in birds and other animals that eat these pollonators.
What about less toxic treatments like neem oil?
This video was made a few years ago before the bans occurred. And the impact is still in question. But if applied only when not in bloom, the impact is greatly reduced.
Neem oil is also useful but only when not in bloom.
Power washing the trees usually works well enough
20 crepe myrtles at $35 per bottles of insecticide is $700 ... I guess they'll be staying black