Mealy Bugs

[Stone Jaguar]

Obviously, a likely outcome in your case here. Just mentioning that some agaves can generate nasty stings all on their own.

Yes, I understand bark scorpions still kill plenty of rural N Mexican toddlers every year, hence ease of availability of MyN scorp antivenine at clinics throughout the country.

[DesertDweller]

Malathion is good for mealy control, bad for bees, fish, herps. I like using it, but smell freaks Joe Public out and makes it a no-no at home and shared greenhouse here.

Hmm. Just how bad a smell are we talking and how long does it persist? I've been tempted to try some before I'm away for a week or so, since I won't be able to quash any new mealy attacks until I return and don't want them going unchecked. Figured it was cheap insurance on the ones that I'm no 100% confident are clean yet, and probably preferable to asking my house sitter to mess with Sevin spray.

[mcvansoest]

In the summer when I used it the smell persisted for about a day or so. It really depends on how heavily you apply it, my wife was not happy about it, so I only use it as a treatment not a preventative measure.
Ever since I got Malathion for a couple of cacti with mealy bugs I have realized that some of the big box stores must be frequent users for their plants as I started recognizing the not so pleasant smell that I often detected while perusing the selection of plants on offer.

Anybody have any experience with it for treating cochineal scale insects? It seems that my neighbor's colony is trying to expand from his Opuntia macrocentra to 3 species of chollas in my back yard. They tried establishing on my Opuntia santa-rita, but I managed to fight them off with frequent hose-downs of that plant, not so effective on the chollas (imbricata, versicolor, and fulgida). They have left all other chollas and prickly pears alone so far.

[Stone Jaguar]

It is quite unfortunate that malathion has such a scandalous (and persistent) odor since it’s a very effective contact insecticide and has relatively toxicity for mammals. I can imagine close neighbors raising the roof if one gives the garden a good spray with it. As I mentioned earlier in this thread, malathion + Enstar is great stuff if you’ve got a persistent outbreak of scale and/or mealies.

J

[bigdaddyscondition]

Wow, I just saw this thread. Sorry for your tribulations, Gee. I hope you get things under control. For what it's worth, I've had no problems here in the Inland Empire with mealy bugs. I've told my sad stories about Oziella mites, and have gotten the education on miticides and environmental controls both in the forums and from Matt Maggio's excellent article to get them under control. Alternating abamectin (Avid) and spiromefesin (Forbid 4F) are my weapons of choice, with Sevin baths when indicated.

For what it's worth, some years ago when I started growing agaves in my yard I encountered, researched, diagnosed, and treated cochineal scale on my Agave montana 'Baccarat'. I treated it with imidacloprid labeled as Bayer Tree and Shrub Protect and Feed systemic granules. It worked great and saved that plant, and I haven't had a recurrence. Now this Bayer product includes clothianidin along with the imidacloprid.

[Stan]

My A.tongaensis almost bit the dust from mealys...but the Bayer worked. A reason why Altman went that way. Its not organic..but one good watering in and that's all it takes.

[Gee.S]

My experience to date suggests that given a chance, mealies establish colonies on certain plants. And that once such a colony is established, the plant is good as dead. Spray until the end of creation and it won't matter. They come back, they come back strong, and eventually kill the plant. Minor infestations can be treated to good effect. In some instances, mealies are wiped out, never to return. In others they eventually return and must be resprayed. I have now lost several Agaves, including two that were very large. Mealies are still here, I doubt I will ever be able to rid my property of them. But they have been savagely reduced. I believe in some instances, they are in the substrate, where they remain out of reach. I have tried termiticides and drenches, and I don't believe subterranean mealies have been adversely effected.

[bigdaddyscondition]

So Gee, try the systemic Bayer Tree & Shrub Protect and Feed. A systemic, once absorbed via the root system, should provide continuous insecticidal activity for months. That must be why we have found it so efficacious. I don't use it on agaves near flowering or in other plants I expect to flower soon because of the toxicity to pollinators, but otherwise it's a great solution for scale infestations of agaves.

[Gee.S]

I have doused with imidacloprid many times. Doesn't seem to bother them much...

[mcvansoest]

For me Malathion has worked, but man that is stinky stuff.

[Gee.S]

Kills 'em for sure, but doesn't necessarily keep 'em from coming back.

[bigdaddyscondition]

Have you tried the granules? https://www.bioadvanced.com/sites/default/files/2018-06/701900%2012%20Month%20Tree%20%26%20Shrub%20Protect%20%26%20Feed%20GRAN%204lb.pdf

[mcvansoest]

I guess I have been lucky then, because I have not had a recurrence on the same plant after treating with Malathion. So far Mealy bugs have been an occasional problem not a huge problem... I have do keep getting cochineal scale back frequently because my neighbor does not treat his severely infested Prickly Pear. Interestingly they leave my PPs alone, but are going for just a couple of chollas...

[Gee.S]

I have mealies and scale. Just checked a simplex I had cleaned nearly a year ago. Now the scale is back -- not too bad, but I had to treat again. Checked the plant 3-4 weeks ago, and it was fine. I don't know how they come back -- and they don't ALWAYS come back, but they usually do.

I have never seen either of this scum on anything but Agaves, and wherever there is scale there are also mealies. So they could be coming from other plants, but I don't know what...

[Brooksphilly]

Hi Gee. Haven’t been around in a while and can’t add anything to the insecticide conversation, but...I wanted to send good wishes about your hand. Hope all is functional and as back to normal as possible after last year’s surgery.

[Gee.S]

Thanks, good to see you around. Surgery is just a distant memory now.

[Gee.S]

So I'm a year into the mealy war now, and while I have made serious inroads, the war is not won, and may never be won. Earlier in this thread, SJ referred to management, not elimination -- they may be here for the duration. Today I dug up and disposed of a couple more large agaves I had attempted to save, to no avail. Why, I wondered.... The answer is that mealies can get deep into the core of certain agaves, and once there, are impervious to chemical treatment. My conclusion at this point is that if mealies are still hanging in, or bounce back quickly after a couple treatments, dispose of the plant, rather than wage an unwinnable war. As long as the plant is there, it remains a source of infestation for neighboring plants. With these guys gone, I suspect the battle to tilt further in my direction, and if mealies are on plants other than agaves, I have not found them. They haven't bothered any of my cactus, but may be in bushes and trees. If so, they will always come back no matter what, and there is nothing I can do about it. Heavy sigh...

[bigdaddyscondition]

...mealies can get deep into the core of certain agaves, and once there, are impervious to chemical treatment...

But why should they be? They should come in contact with imidacloprid and clothianidin too, if you use the Bayer granules referenced above. Especially in the core of the plant the concentration of insecticide should be reliably sufficient to kill the little varmints. I love me some Bayer Tree and Shrub Protect and Feed.

Sorry to hear you've had to sacrifice plants that are overrun with these pests, but I have done the same with agaves that seem beyond hope of successful treatment for agave mites, aloe mites, and more recently agave snout weevils. Don't get me started on those little devils.

[Gee.S]

I am entirely familiar with these products and have used imidacloprid drenches religiously as a weevil deterrent for many years. In my experience it does not eliminate mealy infestations, even at 3x strength. If it actually worked, I would have never gotten mealies in the first place, since ALL (200-300) my agaves are treated twice per year, toward an end of ZERO weevil attacks.

Even SJ, the plant pest pro, suggests that such drenches are only helpful as part of a prevention regimen, and not on active infestations.

[Gee.S]

So I've thought about this some more, and I am going to add imidacloprid granules to the fight. The little buggers generally return to the same plants over and over, so I'm going to toss some granules around these favored agaves. This will be an attempt at long term prevention rather than treatment, because the problem with granules is that it doesn't rain much in the desert

[bigdaddyscondition]

We are not, of course, as dry as the Valley of the Sun here in the Inland Empire, but we go for months-long stretches without a drop of rain. I generally water in the granules right after applying, then again in another 4 or 5 days. Then I revert to the normal drip watering schedule.

Be advised that the brand name has changed from Bayer to Bioadvanced. The product is in the same big blue plastic jug. To further muddy the waters, I see some inconsistency in labeling on the product label shown here https://www.bioadvanced.com/sites/defau ... d-4lbs.pdf" onclick="window.open(this.href);return false; (still showing the old Bayer Advanced brand designation). Specifically, the first page, a shot of the bottle's label, lists clothianidin as the only active product (the formulation I've been using currently contains both imidacloprid and clothianidin). But when you scroll to the second page, it lists imidacloprid as the only active ingredient!

I suspect this is some editing error in the label, but these companies, as you know, regularly switch up ingredients without notice to consumers. They already did it once with this product. So caveat emptor. Read the label before buying. Finally, this product is specifically labeled for mealybugs.

[Gee.S]

Spring has finally arrived, and I just completed a close yard inspection for mealies, and none. They tend to show up on the same few plants time and time again, and all are clean -- for now. I don't know of their life cycles, but do know they tend to return during the heat of summer, so I will continue to monitor. I hit them very hard over the past several months, but suspect they will find their way back, no matter. For now, all quiet on the mealy front.

[Gee.S]

Regret to report that the mealybug horror has still not ended. My landscape/plants appear to be clean except for two agaves, which mealies had colonized last year. One is a large sisalana, and I believe it is doomed, though I have yet to completely give up. The other is A. aurea, which looks just as bad, but is smaller, so I am more hopeful I can save it with massive doses of systemic drench. The excellent article linked below explains why mealies are so incredibly resistant to management.

Managing Mealybugs

[Gee.S]

Another 8' agave gone. After stripping the sisalana of leaves I just pushed it over with my foot. It broke at the base, and the inside was fibrous and black. No grubs, no nothing, just death. It had apparently been dead for some time. Sigh...

[Gee.S]

Just gave the A. aurea a shove and it too was long dead. I'm starting to get a handle on why some of my most concerted efforts were in vain. Because in some instances, plants were already dead.