Root mealys...

[MrSlinkyDragon]

So today i found that a lot of the aloes in my collection at home have root mealys (need to check the cacti and senecios too)... no idea how they came in (probably on one of the plants), found them whilst potting and spent the good part of 3 hours pruning dead roots (most where sent bare rooted). I have ordered some Compo BI 58 off ebay to treat the plants as ive read mealys can be resistant to neonics. But on the plus side, i now have another aloe sinkatana (rooted off shoot) and 2 more aloe squarrosa (3 cuttings in the pot, brought it like that, i thought it was 1 plant)

[Brian]

Amazing where root mealy bugs come from, and what is worse you cannot see them. I find a combination of neem oil and fairy liquid works, that’s if I remember around three or four neem treatments in the soil. If a plant looks poorly there is a good chance that hidden root mealys are in action.

Not heard of Compo Bi 58. Is it available to those of us in UK from UK supplier, looks to be German produced? I thought stuff like this was banned in UK?

[Terry S.]

Compo is our old friend the nerve poison dimethoate which is not sold in the UK these days except for washing your child's hair.

The most effective treatment for root mealy bugs is a drench with a neonicotinoid-containing insecticide. I believe that the active ingredient of Bug Clear Ultra Vine Weevil killer is such a chemical: acetamiprid. A problem with many insecticides is knowing the active ingredient and in many cases the manufacturers keep the same brand name but change the ingredients. So always read the small print.

[Flayzerflay]

I second terry's answer.

I tried all ways manual and organic neem/soap methods even those cardboard strips with insect poison on them but root mealys always won, not sure if it was the same bug but i used to get tiny lavae crawling on the surface.

I caved in after a year of trying and lost some cacti so bought Bug Clear Ultra Vine Weevil killer, gave them a bucket soak, bugs gone and have seen no surface web or crawlers.

The only ones that are now showing signs of mealys are the ones i did not apply it to.

[Herts Mike]

Yes, I've just treated all the Stapeliads with that. Just in case.

[Mike]

I'm increasingly aware that a problem with mealies is those under the rims of pots, under pots, in corners here and there, that survive the best drenching with mealicide. They then act as instant nuclei for reinfection.

I'm also not sure I understand the interval needed between treatments to catch those that may be not caught first time round.

All suggestions and knowledge welcome!

Mike

[Terry S.]

The mealies on pots are the ones which infect the stems and leaves of plants rather than the ones in the compost. Although I can control root mealies with a neonicotinoid drench (chemical names end in "prid"), I cannot eliminate stem mealies from the collection completely. I use a combination of 1 annual drench with a neonicotinoid (May/June), an earlier and a later spray with a synthetic pyrethroid (I think now in Provento but check the bottles for names ending in "thrin"), and regular sprays with SB Plant Invigorator.

As it warms up, mealies seem to have quite a short life cycle so contact sprays tend to be needed more frequently. The mealies on the outside of pots are a problem because our treatments are likely to miss them. This problem is particularly acute if you use square pots for your plants - they fit neatly together with ready-made bug hotels in the narrow gaps between the sides.

[Tina]

We had a beetle infestation last year, they used Bayer Ficam W INSECTICIDE 15g Sachets Spider Mite Flea Ants Bed Bugs Cockroaches.
https://www.ebay.co.uk/itm/Bayer-Ficam- ... 3048922713

Is this toxic to plants ??, i'm guessing it will be but any one confirm, it was very effective

[Terry S.]

Tina, the active ingredient is Bendiocarb which takes out the same nerve enzyme as the organophosphorus compounds. There is some info on Wikipedia https://en.wikipedia.org/wiki/Bendiocarb. This group of pesticides does not seem to be currently licenced in the UK for amateur use on plants.

[Cactusgirl]

Since I started using diatomaceous earth in the potting mix and on the benches root mealy bugs have been almost wiped out in my collection of around 600 plants. I know this because ive repotted 95% this year. Last year i also used Bug Ultra weevil killer twice during the summer season and will do same again this year. I do check the plants individually as often as I can all year round and any leaf mealies I use a tiny paintbrush dipped in pink meths to turn the bug black!