Mealybug treatments that can be applied directly to roots

[Tom Reddick]

Good evening all - there are reams of good advice out there on dealing with mealybugs, but I seldom find mention of using such treatments on plant roots.

I have accepted an opportunity to obtain a small number of extremely high quality original plants. The catch is that the grower had a mealybug invasion a few weeks ago that affected portions of the greenhouse. I am taking delivery of the plants in a few weeks after their isolation in the current owner's hands with a few Neem oil treatments applied. I would normally not even consider doing this- but the opportunity is too good to pass up.

Once I get them home, I intend to repot them all (if possible I will unpot them on site and bring them home bare root), but first I want dip them in something for a few seconds to- hopefully- substantially eradicate any remaining mealies.

For this dipping treatment, I was considering either rubbing alcohol or an insecticide. Trouble is- while these are advised for treating the leaves of orchids, I have never read whether these solutions can be applied to the roots- especially in an application where I would submerge the plants- roots and all- in the solution for up to 1-2 minutes.

Is this safe to do with rubbing alcohol or insecticide? I am happy to flush the plants out in water right after and then respray just the leaves if that would be a useful approach.

 

[Cklinger]

My grandfather would have me spray/dunk some of his infested orchids with either 70% isopropyl alcohol and would emphasize ONLY 70% (nothing stronger, don’t dilute) or in a diluted bleach solution, roots and all. It did the trick and the plants showed no negative feedback towards the treatment. I’d help him do it with his bulbophyllums and dendrobiums, but haven’t yet done it on Paphs or Phrags.

Edit: I just wanted to add that this is how he took care of infestations, if you’re nervous about using 70% iso, I’m sure you could dilute it to what you would deem as safe and test it out first

 

[caffeine93]

Confidor - imidaclopride gets rid of all of them, it's a systemic insecticide, plants absorb it through the roots and it propagates to the stems and leaves, killing any mealybugs when they suck the poison out of the plant. Just keep in mind to use gloves if you happen to use this and also, don't expose the plants outside where they can come in contact with the bees as this treatment is toxic to them. Also, this (and presumably, any other) isn't a one-time treatment, you need to apply it for 3-4 weeks to kill any newly hatched bugs as the eggs can't be penetrated and killed easily.

 

[Ray]

My “go to” is Acephate (aka Orthene). Three treatments at one-week intervals, thoroughly wetting all exposed plant surfaces and drenching the potting medium.

 

[Tony]

I rotate acephate and imidacloprid in my collection.

 

[abax]

Orthene is my killer of choice.

 

[southernbelle]

I just sprinkled Safari granules on wet bark. Next time I watered it dribbled down and dissolved. ¼ teas 4 “ pot to ¾ -1 teas 8-10”. Scale and fungus gnats have disappeared in 3 weeks. I know people who use imidacloprid this way, but safari covers more pests.

 

[Tom Reddick]

Thank you everyone- this is very helpful. I have not had to content with mealies much in the past, so was not familiar with whether the treatments out there could be applied to the roots.

Happily I do not need to take delivery for a few weeks, so the goal now will be do 2-3 full treatments on site over the next month and then ideally bring home fully cured plants.

 

[southernbelle]

My “go to” is Acephate (aka Orthene). Three treatments at one-week intervals, thoroughly wetting all exposed plant surfaces and drenching the potting medium.

Ray:
I agree Acephate is very effective when used this way, however, growing inside in a room prohibits me from using a spray without taking all the plants outside and up stairs which is not something reasonably possible in my case.

 

[Ray]

Ray:
I agree Acephate is very effective when used this way, however, growing inside in a room prohibits me from using a spray without taking all the plants outside and up stairs which is not something reasonably possible in my case.

I with you 100% on that.

When my plants are indoors over the winter, I rely on Azamax and Bio-Advanced 3-in-1 Insect, Disease, and Mite Control, and am not nearly as thorough in the treatments as I am when they go back outdoors. I "hold 'em at bay" until I can get out the "big guns".

 

[tomp]

Safari makes a granular formula, which could be used inside.. Ray??

 

[Ray]

Never used it...

 

[Upfeng]

I just sprinkled Safari granules on wet bark. Next time I watered it dribbled down and dissolved. ¼ teas 4 “ pot to ¾ -1 teas 8-10”. Scale and fungus gnats have disappeared in 3 weeks. I know people who use imidacloprid this way, but safari covers more pests.

Take care, to my knowledge Safari is an Herbicide here in Europe!

 

[Ray]

Take care, to my knowledge Safari is an Herbicide here in Europe!

Must be a different product over there.

https://labelsds.com/images/user_uploads/Safari 20 SG Pkg Label 8-27-19.pdf

 

[Ray]

It pays to shop around!

Safari is 20% Dinotefuran, and seems to cost about $125-$150 for a 12 ounce (340.5g) jar.

Alpine is 40% Dinotefuran and is about $80 for 200g.

 

[southernbelle]

It pays to shop around!

Safari is 20% Dinotefuran, and seems to cost about $125-$150 for a 12 ounce (340.5g) jar.

Alpine is 40% Dinotefuran and is about $80 for 200g.

Wonderful to know, thanks Ray!!

 

[cnycharles]

If plants are infested, then taking out of pot and water spray washing off all visible pests, removing any dead material or sheathing m and then treating is a good practice. If you remove most of them then there are less needing killing or jumping to other plants before they die
I killed a nice oncidium by spraying it with rubbing alcohol. Test a leaf first with whatever you want to use, wait a few days to see what it will do. And it may kill roots where it doesn’t touch leaves

 

[shariea]

I accidentally used hydrogen peroxide instead of isopropyl alcohol a month ago on meally bugs. So far the plant is still alive--no mealies either, although I did also unpot it and dunk it in verified isopropyl also (roots and all) the next day. But it has only been a month. In my defense who (other than my brother) has 2 full bottles of hydrogen peroxide-one in a translucent the other in a brown bottle- in his medicine cabinet? Not much defense, I know, but stuff happens, right?

 

[cnycharles]

A former coworker used peroxide as a dental cleaner
But; peroxide usually isn’t in clear containers, since light breaks it down it could be depleted even before it gets sold.

 

[shariea]

depleted

Maybe that's why the plant isn't dead yet? I used the stuff in the translucent container.