Must...kill...root....mealy!!!

[zee_werp]

Hi all

I was doing a bit of repotting today and to my utter shock and disgust, noticed some small white fluffy spots in the soil around the roots. Upon closer inspection I found a couple of mealy bugs, root mealys!!! Little fuckers.

Anyone got a method of killing these little shits? Most of the cacti I saw them on aren't showing any ill effects, but for all I know it could just be a matter of time. A couple of them though have slowed their growth and thats why I was repotting them.

I've used the search engine and found a few ideas - neem oil soak, diluted alcohol soak, chilli/garlic soak, etc. but I don't know which is the best (ie. kills them or stops reproduction with minimal damage to the cactus). Any suggestions, experiences, etc. much appreciated!

It's not too major of an infestation but I want to nip it in the bud while I can.

[Gunter]

I have had a lot of council on this topic through cactus and succulent email groups.

There are many methods, hot water is one in some areas, it kills all eggs, and bugs at temperatures the plants roots survive. If that sounds worth hearing more about I'll see if I can get the details.

[zee_werp]

So kind of a low temp pasteurisation of sorts? Sounds interesting. I'd be keen for more info. Anything to kill these bastards.

[M S Smith]

Join the club man, I sprayed off all the soil on all my infected plants and let them sit out all winter without soil and on most of them they went away. I then repotted everything in April/March (our spring) and if I caught any more I sprayed off the roots again. But what do you know, in bringing them in this winter I checked a few and they are still lurking. I got neem oil and will try that on the ENTIRE collection this coming season.

I have been infested for at least 3 years now I would say, and the little bastards eat the roots and prevent them from being able to take up water. I had plants that though taking in enough water to stay somewhat healthy haven't grown at all. I've had other that stopped growing and started to thin.

I started mixing some of the good old "brown dirt" from my area in with the loose cactus soil, and it has proven to work quite well far as it seems to keep the mealies from being able to move around as much (if it doesn't just cause them to expire - I don't know).

Ugh, thanks for the reminder

~Michael~

[Gunter]

I check my roots often, I still have some in my collection. I have not tried the hot water method.

They are not too hard to keep in check, but can be hard to eradicate and a small population left unchecked easily gets out of control. I'll look through my cactus group emails...

Bob Schick suggested the following:

Your alternative mechanism of soap reducing the surface tension of the

water as the mechanism for killing mealybugs is evidently the correct one.

When I apply the dishwashing solution topically to a plant infested with

spine mealies, the plant dries out in just a matter of mintues. Yet, all or

most the mealies on the plant -- one can never be sure -- succumb after

that brief period. Apparently, the detergent solution fills the respiratory

tube system to their finest branches, right to the bugs' tissues and any

meaningful diffusion of oxygen entering through the openings to the outside

ceases, rapidly killing the mealies due to anoxia. I presume that root

mealies can be killed by the same mechanism and before any deoxygenation of

the medium or loss of water throught the insects' cuticle can take effect.

Thus, prolonged immersion in the detergent solution does not seemnecessary.

I use the same solution on Argentine ants at home. They die within two or

three seconds after spraying or dousing. They obviously have a higher

metabolic rate than mealies, so the death of the mealies probably doesn't

take that short a time. I also end the lives of grown black widow spiders

by immersing them in a container of the detergent solution. Their passing

away by anoixa takes longer, perhaps fifteen minutes -- I never timed it --

but that is probably due to the difference in a spider's radically

different respiratory system.

Leo Martin suggested the following:

There aren't any non-labor-intensive chemical treatments for mealies that

will work short of organophosphates or nicotine derivatives. Parasites

provide control but not eradication and are tricky to manage. Plus they

have a tendency to want to fly away, so they work best in closed or

tightly screened greenhouses.

One can make a nictotine solution by soaking an ounce (close to 30g) of

cheap smoking tobacco in a quart/liter of water with a few drops of

detergent. This will be very effective against almost all insects. Smoking

tobacco is infested with tobacco mosaic virus (TMV) so this shouldn't be

used on plants such as tomatoes or other Solanaceae that are susceptible.

I don't know whether cacti are susceptible to TMV.

Nicotine is one of the most toxic nerve poisons known. It kills almost all

animals. I've always been startled that people worry about pesticide

residues on their smoking tobacco, but they do.

The problem with the labor-intensive treatments is that unless you can

treat your entire collection within 2-3 days, or you have two very

widely-separated growing spaces that don't share air circulation so you

can isolate the treated ones, the mealies will migrate back to the treated

plants from the untreated ones.

People have written about hot water treatment. If you

wait until fall when the humidity is low again, say under 10%, and nights

are cooling while days are still hot, your cacti will once again begrowing actively.

Just take a bucket, fill with water and add some detergent, submerse a

plant in the bucket, and leave it there for 12 hours. The detergent will

ensure the mealies get wet, and they will drown.

We (warm climate growers) can get away with this whereas most other cactus growers can't. You

will have very few losses this way. I've done it and it works.

I wouldn't do this to a plant that looks weak. Such a plant should be

unpotted, have all the soil removed with a jet of water or air from an air

compressor, have bad roots removed, be treated with alcohol, set to dry

for a day in the shade, and repotted in fresh medium.

And, before you treat, be sure your growing space has been wiped down with

bleach or alcohol. Mealies can hide for some time in crevices in growing benches.

I can't locate the hot water treatment info yet...

[M S Smith]

I smoke Jester Premium Rolling Tobacco that I roll myself and is without additives. It comes in 40 gram (1.41 oz) packs and cost about $3.50 US.

I look forward to using a whole pack or two come spring with detergent. Any recommendations on detergents to use?

~Michael~

[mescalito]

Far out man I smoke Champion Ruby tobacco and it costs $12.50 for 30g (1oz)

A friend of mine in Canberra throws all his butts into a milo tin and then soaks them for a few days in water and CAREFULLY strains off the butts taking care not to get it on his skin.He reckons this works a treat on his tomatoes plus he gets to smoke the baccy first ;-)

[M S Smith]

I'm seriously thinking about mixing a nicotine, neem oil, detergent concoction.

Anyone imagine any trouble with this?

Seriously, I got to get them things out of my plants.

~Michael~

[Gunter]

Neem granules can last for months as a very strong deterrent, I have considered them as one of the best options in the war against mealy bugs.

I am sure you are wise enough to test any concoction on a plant or two before more widespread application, that sounds like it would be effective and I'd love to hear a success story here.

[faslimy]

are the neem granules something you would mix into the growing media? The soil I use has something called Suscon Green added and I havn't seen any root mealys.

[Gunter]

Yes or topdress with them.

[zee_werp]

OK, so I'm going to have a crack at this this weekend.

I'm planning to dunk the cacti (just up to the top of the pot) that are small enough for me to lift without breaking my back, and the large ones I will just thouroughly douse with the stuff.

But I am still not settled on what my liquid mix will actually be. I am thinking of including any / all of the following:

-Neem oil

-Detergent

-Methylated spirits

-Garlic

-Chilli

-Fresh tobacco leaf

The neem oil and detergent will be the main ingredients, I was just thinking the others as minor additions for extra defence, with concentrations erring on the side of caution for the first application.

Any suggestions on what specific concentrations I should use for say 50 litres of the stuff? Any further suggestions before I go ahead and do this?

Oh and MS Smith, what is brown dirt?

[AndyAmine.]

I had a bit problem with Alcohol on cacti, I was told to spray some Isopropyl-alcohol onto a cacti to rid them of scale and or the rot I cant rememebrr now, anyway, the cactus didnt like it at all and it burned the hell out of the skin. it all went black but happy it has now healed with the normal colored scaring.

I know your not using it on the top 1/2 of the cacti but even still, it may still be quite hash on the roots.

[zee_werp]

Thanks for the warning - I'll scratch that one off the list.

I've had successful results with applying meths directly onto scale but I have never tried applying it direct to healthy flesh or roots.

[Rev]

ive used 70% meths the *wipe* the cactus clean of scale but it doesnt sit about

Nicotine is one of the most toxic nerve poisons known. It kills almost all

animals. I've always been startled that people worry about pesticide

residues on their smoking tobacco, but they do.

LOL thats funny shit

[zee_werp]

Just an update here.

I have given my entire collection two neem oil treatments so far.

What I did was firstly water the cacti so that the soil was moist, just so that the neem oil solution would soak in easier.

Then I applied a solution of about 20ml neem oil per 8 litre watering can to them. I just added however much seemed adequate to soak through the root system of each plant. I then sprayed down the plants with the hose on sprinkler setting, to wash any excess oil from their skin.

Since then I have repotted some cacti, including some that I had known to have mealy. Things were looking good. I only found one live mealy bug. I found a bit of dried out looking mealy bug sign, and overall things are looking healthy.

One note of caution though - about 5 days after the first treatment, one of my scops developed some black blisters near its base. I chopped it, the tip is now rooting and I took the stump far far away to see if it pups or anything. I'm not sure if this is related to the spraying. Scops seem to be pretty vunerable to skin diseases compared to other trichs, which is unfortunate as they are nice looking cacti. Slugs also seem to target scops more than my other trichs.

So overall so far things are mostly successful, my one note being use with caution on scops and be sure that any splash-up is thoroughly washed off on them.

[Gunter]

Thanks!

[zee_werp]

Just thought I should add this note - when I say 'Neem', I refer to the locally avaliable brand, Neem 900 EC. On the packet it says "Neem 900EC contains neem and other botanical oils in an emulsifiable concentrate". In other words it does not need added detergent. If you are using just plain neem oil I think it'd be a good idea to add a few drops of dishwashing liquid, to help penetrate the mealys waxy coatings.

I actually added a few drops anyway, just to be sure. I'm also about to email them to ask what the extra botanical oils are thats in it.

EDIT: No need to email, it seems they've updated their website since I last visited.

http://www.suntec.co.nz/neem.htm

So it seems the ingredients are:

Cold pressed Neem seed kernel oil - "Insect growth regulator"

Indian Karanja oil - "acts as a synergist enhancing the effect of neem"

Citronella oil - "general insect repellent'

"These ingredients are systemic to affect pests not directly contacted by the spray."

"Neem 900EC is non-toxic once sprayed on plants, and is safe to use."

[zee_werp]

Just another update here guys. Well the treatments I used of the above mentioned Neem Oil seem to have worked a treat. Populations took a significant clobbering and last weekend when I repotted a couple of specimens that were known to have had it, there was no sign of mealy. So things looking up at this stage in the war. I guess it goes to show the importance of nipping it in the bud when populations are not too established.

And now my latest weapon in the ongoing quest for a mealy free collection - Neem Pellets! Picked them up a couple of weeks ago, I've started throwing in a handful per 10 litre bucket of cactus soil that I mix up. I'm hoping this will function as more of a long-term preventative measure. Also plugged 4 or 5 into the soil of all my other cacti which are still a wee way off repotting.