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On Dendrobium Leaf? Disease or Pest?
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I’ve been dealing with what I believe is “white fuzzy” stuff on some of my Dendrobiums. I found this on a newer growth leaf. This looks less like “white fuzzy” stuff, but I cannot tell if it’s a pest or just advanced white fuzzy stuff.
Any ideas? I’m feeling extremely discouraged with what’s going on this. Thank you! |
You're looking at mealy bugs. I don't know what the latest and greatest treatment for them is, I fortunately haven't had to deal with them in a long time. As a stopgap measure you can remove them using a cotton swab dipped in rubbing alcohol and swab them off with it, but generally the whole plant needs to be treated. Is this a newly aquired plant? I'm sure someone will chime in with the latest recommended insecticide.
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That sure looks like the dreaded mealy bug. Take all the affected plants and separate them from your others. There are several options and everyone has differing levels of success treating them. Rubbing alcohol can help but you need to make sure you wipe them off with it and don't let the sun hit your leaves after until they dry. People also use Neem oil o insecticidal soap. If you search mealy bugs in the forum you'll find tons of posts with various remedies.
They can get in the mix too so treat that as well. My orchids are mostly outside and they can get pretty bad here so I moved from at home organic to a systemic preventative. They can transfer to other plants by air movement. You'll want to be diligent in retreating to make sure you get them all. They're resilient sneaky little....well you know. |
Okay. Sad but hopeful! Explains a lot!
Thank you! |
Mealybugs crawl far from your growing are to lay eggs, which remain viable for up to two years. You need to be very vigilant.
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I extend my sympathy... Indeed, vigilance is key.
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KILL
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Hi all, and thank you for your various advice and tips. I did feel a lot murderous as I went through and sprayed and doused with pesticide and insecticide soap.
Now, I am assuming that the little flying whatnots I am seeing from time to time are fungus gnats, but I suspect they may be male mealybugs. Feeling my murderous rage at these bugs eating and destroying my plants, I am trying to determine the best way to kill the flying ones that are not already on leaves or on soil, getting a treatment. My husband, the non-orchidist, says bug bomb. Just grab one at Lowe's and let it off. Somehow, though, it seems like it may do more damage to what I'm trying to keep alive that damage to what I'm trying to kill. Does anyone use a bug bomb? If so, anything that you recommend? If not, what should I do about the little flying guys. There's not many, but, now that I see a problem, I am wanting to completely remove all the nasty mealys. |
That indiscriminate bug bomb not only could damage plants (read label carefully) but could also be very bad for you and your family and pets. First, is this in a greenhouse or in the house? As for the flying things... instead of killing things that you haven't identified (and could be harmless or even beneficial) take the time to observe whether the problem comes back or not. And if you treated your plants once, one is NOT done - you need to be treating once a week for at least 3 weeks to get multiple generations. Pest treatments need to be done surgically. You don't want to kill your plants, yourself or family or beneficial/harmless insects that the environment needs, you don't want to generate resistance in the target.
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Hi Roberta, well, these are plants inside and not in a greenhouse, so, yes, the potential harm to humans/animals is definitely a concern.
As for treating them, oh, you bet I'll be treating for several weeks! After seeing the very mature mealybugs on a couple of leafs and seeing evidence of infestation in several plants, everyone got treated. But, noticing one or two flying bugs, I suspect these are the male mealys looking for females and not another random bug that could be beneficial. They're too small to identify as potentially safe, and, well, they're going to have to go due to guilt by association. Tiny little bug was likely a mature male mealy or a fungus gnat and not readily identifiable as a "friend". What I did do, since I had my insecticide soap spray in my hand, is I just sprayed the insect as it flew by. That seemed to knock it down and, I suspect from what I've seen of mealys, that the spray likely killed it. Is there a way to treat the area in general as well without harming the plants? And, honestly, the only thing a bug bomb, in my mind, would do would give me a small amount of peace of mind, not feeling creeped out by my realization of an infestation. I hate to be squeamish, but, I am. |
Pest control doesn't lend itself to shortcuts. Insects were on the planet long before we were, and are likely to be there long after we're extinct. Zapping that one with soapy water spray is harmless. You could put ant spray on surfaces, it sticks around... and also doesn't smell very good, the odor sticks around too. If you're sharing living space with the plants you are somewhat limited in how aggressive you can be, especially on the airborne ones. You really don't want to be breathing a constant dose of pesticide. But a drench of medium with a systemic product (which will kill adults that might be lurking, and make the plant unappetizing and likely fatal for any that manage to grow up) should help a lot. If you want to go after larvae, a drench with a BT product could also help. There are bigger guns, such as insect growth regulators (like Enstar AQ), which tend to be extremely expensive, not cost-effective for small collections. From a practical point of view, just continued vigilance and treatment when you spot a problem, will be your best bet. Not something that you can put on "automatic".
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That's sage advice, Roberta.
Sharing the space and enjoying my orchids are two things that go together, but sometimes sharing the space isn't very appealing when there's creepies around. However, this has been a learning process, and me and many orchids will come out the other side of it intact. |
They'll land eventually and try to eat and then.....r.i.p. I like to use a systemic to help try to prevent some as well..keep doing your weekly treatment until they're gone. Remember they'll get your roots too so rinse well. Of all orchid pests mealys just make you cringe don't they?
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Oh yeah. They’re just ….. <shudder>
But I’ve sprayed and doused. I think the one thing for orchid enthusiasts — that I’m dealing with at the moment, too — is to keep from over treating a problem. Too much “love” can be just as bad if not worse. I’m going to give them some time. Keep an eye on things but wait. |
Update: after stressing about this, and perusing various advice and sources, I talked with a local ag person whose advice was very helpful and worth sharing to all.
He suggested, first, that the organic or non-chemical treatments may be ineffective with an infestation. One or two, fine, but on several plants and seemingly spread out, the organic stuff will do little. In fact, the nitrogen byproduct runoff is more harmful. He highly recommended imidacloprid as a systemic treatment to repel mealybugs and other unwanted bugs. I have seen other posts that recommend this treatment. I leaned heavily towards this solution since I found some mealybugs on my vanilla vine, which has plenty of leaves and new growths and lots of places for mealybugs and others to establish themselves. If that will deter them, then that can help other plants remain pest free. The local hardware store versions of pesticides will be highly diluted for a consumer (non-professional) user. Keep that in mind when applying, depending on the severity of the infestation. In other words, watered down pesticides can’t be as effective as a professional strength. BUT repeated applications at those lower doses may do less damage to plants. What I am seeing for most imidacloprid treatments from my local Lowes is that the treatments can be effective for up to 6 months. That doesn’t mean I will wait to treat again in 6 months; once the problem is “under control”, a periodic maintenance application is recommended. I have tossed 5 plants as a result of this: 4 were dead or so far gone the treatment would’ve likely killed them if they weren’t already dead. I was nursing them back but let them go. One “rescue” phal was tossed yesterday. Its root system was very poor and damaged and the undersides of its few leaves were communities of mealybugs. It was just being eaten and acting as a host for the rotten creatures. On the plus side, I feel I’m coming out of this learning a LOT and very grateful for all those who’ve posted directly or otherwise added to the ongoing discussion here. Now, I’ll be following Roberta’s advice and be supplementing with Kellpmax and fertilizing to help strengthen everyone though treatment. And, on the plus side, I do seem to have some plants that are continuing to have new growth carefully watched), with one even developing some new buds! Question: I was using some gardening velcro to secure stems. Any risk of this being a hiding place for pests that anyone has seen or knows about? |
I use that gardening velcro a lot, and have had no problems with bugs hiding under, It's really convenient. It is loose enough (with somewhat sharp edges) that it is likely not a particularly welcoming environment for the nasties.
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Thanks for your thoughts, Roberta. I definitely went “scorched earth” in trying to remove these mealybugs, removing anything non-plant material that looked like it could be a hiding place. It's getting time to repot/secure stakes in several plants anyway, so it's an opportunity to tidy up.
I really, really appreciate the help and advice. I can't stress that enough. Thank you! |
Hi everyone. I'm on day 17 of the mealybug fight. Thank you for all your thoughts. If I can share, my appreciation for your help is tremendous; I feel somewhat ashamed and embarrassed that I am having this issue. I should have been more wary and cautious and not so cocky and ignorant that this wouldn't happen to my plants. Plus, too, I am seeing what feels like a rapid decline from plants that seemed to be thriving, and there's definitely a feeling of frustration and powerlessness.
All that being said, I have some more questions on this topic, if I could post it out to the collective experience/wisdom of the group. I've looked through the board to see if there were already posts on these topics. If I missed something, please redirect me. 1) Mealybugs and roots: what is the value of dousing the media/plant with a diluted isopropyl alcohol solution? Or a hydrogen peroxide (H2O2) solution? I see some recommendations for this. I am extremely hesitant to do this, since it seems like it may be drying or damaging to the roots. I did see a post about H2O2 use on orchids which I will revisit, but I am leery to soak my plants' roots in it for fear of damaging an already fragile plant. 2) I have seen some recommended treatment schedules posted. Would anyone be willing to share their treatment schedule for an infestation and what's worked/not worked for them? Partly when I do an internet search, there are LOADS of suggestions, the majority of which are organic. After the first day's treatment, I realized organic was not going to be enough. I have insecticides which I have been using in a schedule of every week (2x) then moving to 10-14 days (2x), then as needed, watching for phytotoxicity. My concern for a treatment schedule is watching the life cycle of the mealybugs and catching all them. 3) Any recommendations on a long-term, preventive treatment and intervals for using? Thoughts on needing a routine preventative on house plants? I have seen estación seca post about dunking in soapy water. I don't feel that's a method I can use to deal with the infestation, but I would like to use that as a preventative. I believe I may need a preventative, even with houseplants. I have dogs who will get into our garden. They have brought visible critters in on their coats. Although I don't know/believe this is how I got my current infestation, I suspect that this may be a possible means of transportation. I live in an agricultural area. We have loads of pests and plenty of farmers, vintners, orchardists, et al. who are concerned about crops and spreading pests. There are likely many ways that bugs are introduced into a household plant collection, but I have every expectation that new infestations may occur. Sorry for the very long post, but thank you for your thoughts and for your time. |
First, Isopropyl alcohol will be quite useless as a drench, don't know if it will harmful but certainly not going to solve your problem. Did you check out the YouTube video from isurus79, here's the link to his post:How to use hydrogen peroxide on orchids - Orchid Board - Most Complete Orchid Forum on the web !
This is an approach that may be safe for roots, involves only short contact time. But whether it kills the bugs? It is probably time to stop messing around with "organic" half measures and break out some bigger guns. Bayer's BioAdvanced has some systemic properties. You likely can still get imidacloprid by getting Merit lawn treatment though you can't get that in sprays any more in most places. Some Merit granules in the pots might be useful. The really big guns (such as Enstar which is a growth regulator, low toxicity for non-insects) are really expensive The schedule... whatever you use, you need to do it weekly for 3 or 4 weeks at least. Ideally, you have more than one pesticide, with different mechanisms, to avoid resistance, rotating the different products. Other Board contributors have more experience with the various products. |
I am following this. I have had horrible infestations as well so don't feel bad! Mealys are just ugh. Definitely makes you cringe. I have used bonide granules but as everyone states they wash right through the medium (they do still work but not as well as liquids. This was just my quick fix until I could find a better solution, also worth noting when I water I soak so I imagine that helps the granules be absorbed a bit more). I have done organic but like you a systemic preventative is necessary for my environment so I'll be lurking to see what others recommend and sending good vibes to you for the death of all things mealy!
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While I have not had to fight mealies (yet) I have dealt with other insect pests. My go to is malathion. I mix it per label instructions and put some in a spray bottle. Then I spray every surface of the plant until it is running off. I also drench the medium. Three treatments at one week intervals should eliminate anything living on your plant. (The stuff stinks so do it outside.)
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What I've learned in the various "how tos" out there is that there is a theme of organic - organic - organic. There's very little information on what to do when you have an infestation. The information, too, is somewhat generic and seems to repeat itself, including information that's really poor advice. Living in an agricultural area with not new plants: once you see one, you've not see all of them. Assume there are many more. Quote:
Although he gave me some concentrated pesticide to apply, I was able to find some in the BioAdvanced line. Their "Concentrate Insect Killer" contains both imidacloprid and beta cyfluthrin (which is a contact insecticide). I used that as a douse mixing in appropriate amounts with water. Note that imidacloprid is the insecticide used on topic flea/tick treatments for animals. Although this makes me feel a little safer with using it, I still use nitrile gloves when applying and keep good air flow. Quote:
I'm definitely discouraged after 16 days of treatment. I have found Enstar and am getting some, in the hopes that I can get the pest situation under control. Quote:
A friend/colleague of mine, whose husband teaches in our local college's agricultural department, has an infestation of mealybugs on her succulents, she said. I told her what I had used and had asked her about neem oil. Her response was that many of the organics, in order to be effective or to have similar efficacy as the chemical pesticides, must be used in such a concentration that resulting byproducts cause more damage than the chemical pesticides do. That being said, I think there's a place for organic pest control, but if I'm not interested in merely providing an expensive meal for mealybugs or willing to throw away my orchids. I feel I'm at a point where "it's them or me". If my questions or the advice others provide here can be helpful, please lurk. But I've pulled out the big and now bigger guns. They're likely in my phal. potting bark and have taken some of the joy out of my orchids. Quote:
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IPA is fine for killing a mealybug or two It is very satisfying to watch that waxy fuzzy white coating dissolve leaving the naked bug that can then be dispatched. Certainly not up to the task of dealing with an infestation. It's just for the occasional onsey-twosies that might show up on a phal, etc.
Yes, definitely time for the stronger measures. If you use imidacloprid one week, maybe enstar the next , then back to imidacloprid you have a fighting chance. |
I don't find mealy bugs to be nearly as frightening as most other people seem to. I have not used pesticides for mealybugs nor scale in many years, and I have never used pesticides for spider mites. I watch my plants closely. When I see bugs I treat quickly. I usually use 70% alcohol spray for mealy bugs or scale, alcohol or dish detergent in water for spider mites. If there is a repeat mealy bug or scale problem, I submerge the plant completely, pot and all, in slightly soapy water for 4-8 hours. This kills the mealy bugs or scale. There may be leaf damage with soaking from a dense infestation, with water entering the plant through many tiny bite marks. I soak those plants for 2-4 hours.
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Prevention (and early treatment when a problem appears) are certainly best. Alas, it sounds like for the OP, that ship has sailed. I have been fortunate enough to have not had any problems this bad. But clearly other people have... there comes a a point where one has to get the problem knocked down to get to the stage where prevention/maintenance become options.
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You should see some of the cacti I've salvaged from people who thought they were supposed to be completely white and fuzzy.
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I have a couple of plants, notably a rhyncholaeliocattleya that, although it came to be with an injured leaf, the plant is looking worse for the wear after treatment. I fear/wonder if I have mealys living and feasting in the media. ---------- Post added at 06:05 PM ---------- Previous post was at 04:51 PM ---------- Quote:
estación seca, I like your soaking method, and I believe I can get my plants to a point where this is feasible. Are there orchids you do not recommend for this soapy soaking treatment? |
Don't soak think-leafed or tiny or heavily infested things for more than a few hours. Don't soak unless you can dry them quickly and keep them fairly warm while they're wet. I wouldn't want to soak Phals when it's 62 degrees and the tap water makes you shiver.
And remember mealy bugs crawl away from plants to lay eggs. Be always on guard and spot spray when you see just a few. |
Hi all. Just an update .... really my observations. For any who stumble across this or are otherwise following with their own mealybug issues, here's what I've done and what I've observed.
Every orchid got a soak and spray down this morning with cyflurthin (last week was beta cyfluthrin and imidacloprid). I am keeping records of when and what I apply. I am keeping a photojournal of orchids and progress, at least until I feel I'm better at observing. If you are reading this and do not otherwise keep a journal, I have found this to be invaluable. I keep a journal of watering schedules, noting when I fertilize. I take pictures of my orchids to help me document changes (usually positive, but, lately, negative). A few days ago most got a little fertilizer (those who were due for watering). Throughout I have interspersed water with kelp solution (will be switching to the kelpmax). I had not thought about the damage that the insecticide may do to the plants. The fertilizer and kelp/probiotics will, hopefully, help all plants continue to be strong thoughout treatment and withstand infestation. Speaking of infestation, so far I have documented a few flying what-nots. (I don't have a microscope, but I feel confident that they're male mealybugs.) But I have only seen/killed a few females. That's not to say I haven't seen the white fuzzy stuff around, but I haven't seen a lot. What I mean by that is that I have seen no more than about 10 fuzzy spots. I had one plant that was in poor health, poor roots, and it already had about three fuzzy patches under its leaves. After a short funeral, it was in the trash outside. This was my "infested" plant. So, here's my question for anyone who's got a thought: with what little I saw, do I have an "infestation" or do I have just a "problem"? Thinking: in Texas, the mantra as a kid was, "if you see one cockroach, there's many more you're not seeing." Does this thinking apply with the mealybugs? I am assuming yes. On the one plant where I first spotted a mealybug (Jan 20), I found a second one about the same size 17 days later (Feb 6). Mom and daughter or is this three generations? Fri, Jan. 20: first spotted Sat, Jan. 21: insecticidal soap spray (Potassium Salts of Fatty Acids)/insecticide douse (tebuconazole, tau-fluvalinate) Sat, Jan 28: insecticide douse + spray (beta cyfluthrin and imidacloprid) Tue, Feb 7: insecticide douse + spray (cyfluthrin) Note: I found the latest mealybug Feb 6; I sprayed/doused with the tebuconazole, tau-fluvalinate after seeing the first one on Jan 20. Is it fair to assume that the Jan 21 pesticide did nothing? It's not like I had one then POOF a second one appeared almost 3 weeks later. Also note: I am using the Lowe's/home improvement box store off-the-shelf products, and I'm mixing to label strength. Having some farm stores/ranch stores nearby, I may have access to some stronger mixes, but I am going weaker, first, since I'm applying to orchids. And, a final note: the value of keeping a photojournal is that I am looking at how long my orchids have had mealybugs. I can spot crawlers two months ago on the plant where I first noticed "the problem". The value is tracking progress and seeing now what I did not see before. It's definitely helping me learn! |
I don't think mealybugs on plants are a serious enough problem to bring toxic poisons into my house. I think you're going way overboard. From what I can see and read you only have a few. If you keep an alcohol spray bottle with you and regularly spray all the patches you see, the eggs will eventually hatch, you will kill the adults, and with time they will mostly be gone. It's like getting rid of a patch of bad weeds in your garden: It takes persistence for several years, then you can relax.
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Funny you say that…..
Looking through the photos, I was trying to see if I could pinpoint a culprit or just when then mealybugs arrived. What I did see what a problem that’s been obvious for a couple of months. Several crawlers are obvious in pictures. At least one or two more mature (though not as big as what I’ve recently killed) mealybugs were obvious. The fuzzy stuff was there for at least a week before I clued in. And I’m no closer to identifying how they came in. I am very grateful for the tips and thoughts you’ve all provided. It has definitely helped me feel like there is a light at the end of this tunnel and keep a perspective on this situation. |
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Another question on mealybug treatment: what should I be expecting for treatment and outcomes?
I'm just trying to assess if my efforts are working or not. If there are any who've been successful in their process, I'd love to know what to expect. What I've done: I have doused and sprayed with rotating insecticide now for two weeks. (Another application in a couple of days.) First application was insecticidal soap the week before that. What I've observed: Problem identified three weeks ago. Now looking at orchids mostly clear BUT today identified a V. falcata with what looks like clear signs of it becoming a mealybug buffet. I've also observed some "stuff" on leaves -- miscellaneous white stuff that I cannot tell if it's residue or mealybug material. I am armed with q-tips and isoprophyl alcohol, which I use to wipe leaves and crevices. Thank you, everyone, for all your help with this problem. I have really appreciated and absorbed the information everyone has posted. |
Keep a magnifying glass with your plants.
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Just had a thought about mealybug source... Do you by any chance have Cyclamen or Hibiscus around (as house plants)? Those tend to be mealybug (as well as whitefly) magnets.
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I have hesitated to repot several orchids. I was hoping the douse would help. Perhaps I’m just seeing in between generations. ---------- Post added at 10:28 PM ---------- Previous post was at 10:05 PM ---------- Ah, okay. Here’s a potential problem: I have a vanilla that’s growing around a pole and it’s lovely and leafy. With white spots around its leaves. It’s also been treated with insecticide, but it’s got loads of hiding spaces. I wouldn’t suspect it’s any more delicious to mealybugs than my other orchids, but it’s got some great hiding places. |
Studying the problem a little more, and taking from the advice given here:
1. ES’s thoughts, that mealybugs get in all sorts of places, is true. Even a good first spray may not get them all. 2. The idea of treating for several weeks is because, partially, from #1 and partially that hitting all the generations can be hard with 1 application. If you can rid an infestation after 1 application, you may share and be hailed the supreme person you are. 3. There’s a variety of ways to treat for this pest, and there’s loads of advice out there. Some of it isn’t so good and can even be harmful to your affected plants. Most of it isn’t bad advice, though, but research your issue. 4. Treatment may cause some damage to your plant. Just because you’ve treated and see a little decline doesn’t mean your plant is a goner. Watch for signs of ill health and, just like treating a sick patient, be sure to nourish your affected plant so it can rebound. 5. Patience is a virtue. If you use a systemic insecticide such as imidacloprid, it’s just gonna take some time for the mealybugs to die out. Develop a plan and stick to it. I’m just collecting some thoughts for others. Truly it’s been an interesting experience dealing with mealybugs. I hope to come out of this experience wiser. |
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And who may be tired of me posting on this subject? :hmm
However, I'd like to share my latest thoughts: 1. I have treated for three weeks (1 week apart) with insecticide. Whatever mealybugs I've found have been few and far between. 2. I have truly appreciated the wisdom of all who've posted. I feel I've learned a lot. I have taken Estación's advice and am using magnification to try to monitor. Wise advice. This has helped me see better what's happening. 3. By not only treating but also nourishing, I am seeing new growth! I've included a picture of my den. Miva Abracadabra bud, but I am seeing some new root growth as well and new shoots. 4. My last treatment will be the Enstar II to try to sterilize whatever mealybugs may be left. 5. What I have done is use not only the pesticides, but spot treat with isoprophyl alcohol and use sticky paper to capture any wanderers/flyers. I caught 1 male mealybug flyer who looked young. I'm not saying the fight it over, but I am feeling like a corner has been turned. I have also noticed that the insecticide treatment is harsh on the plants. I hope to evolve to Estación's recommendation of soaking or to treat with insecticide annually or semi-annually as a precaution. Fortunately it seems that all plants seem to be stable if not growing despite the treatments. I had to weigh the chemical treatment versus the damage the mealybugs were doing, and I felt this treatment was going to be the best long-term solution. I'll continue to post updates, but I have treated as follows: Week 1: imicloprid douse + cyfluthin spray Week 2: cyfluthin douse Week 3: imicloprid douse (using commercial insecticide with an adjuvant. Week 4: Enstar douse (planned) Thank you, everyone! |
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Okay, again, another post, but a “happy ending” or, at least, seemingly past the main mealybugs issue.
Attached is a pic of my Bc. Theresa Ricci. After treatments for mealybugs, it had a leaf that didn’t look good. But I’ve watched develop some pretty, new roots. I thought I’d share some happy news. The root tip colors are quite pretty. I got this late 2022, so I’m hoping I might see some blooms from it soon. The second is a den. moniliforme with its pretty variegated leaf with pink on it. The third is my den. Jacquelyn Thomas with three new growths! Partly this is us starting some springtime growth, but, this is why I love spring! And, this share is a way to give an update and hope but a very big thank you to everyone’s thoughts and shares. It was so helpful. I was also going through some work stress, so everything (stress) seemed amplified. You don’t know how much your kind words here helped in many other ways, too. Thank you. |
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