Article on systemics and mealy bugs

[DaveW]

http://www.gpnmag.com/article/mealybugs ... ecticides/

[gerald]

Great if you're in the US, but none of the currently available insecticides in the UK are very effective.

Bi 58 works a treat, but you can only get it on the continent, and is probably illegal here.

[Jim_Mercer]

Bayer seem to be changing everything, current Provado formulation no longer lists mealybug as one of the targets. Last time I checked their web site there was nothing listed for mealy bug but today I found they now recommend Baby Bio http://www.bayergarden.co.uk/Products/b ... nsecticide which has Thiacloprid as the active ingredient.

[DaveW]

I thought the EU banned anything that killed bees, yet you can freely get insecticides from Portugal with this bee killing warning off EBAY even though Portugal is in the EU?

http://www.ebay.co.uk/itm/Professional- ... SwRGlXqFkG

http://www.ebay.co.uk/itm/Garden-Plant- ... 2233439384

One wonders if Britain as usual is over interpreting EU regulations (known as "gold plating") if these are still on sale in the rest of the EU?

[Chris L]

Late last year I went through every single pot and tray with a paint brush and a bottle of Lavender Diffuser Liquid. Every sign of a mealy bug or egg nest was dabbed with the liquid. The bugs/nests just shrivel up and go a wet brown colour.

After that I sprayed everything (several times) with Neem Oil till it was time to stop watering.

This spring/early summer I am hoping to re-pot as many plants as I can. Any infestations will be dealt with using the Lavender. Early Sprayings and Waterings will have a Neem Oil element to them. Any visible mealies are dealt with there and then with the Lavender. "I'll sort it next time I am in the GH" is NO GOOD!

I think the problem we always have with mealies is that they hide under the necks of the plants, thus missing a spray application and the worst infestations are on sick plants that have more than likely either stopped growing, or have lost most of their roots, thus get missed with the soil drench.

My (limited) understanding is that Neem Oil is supposed to disrupt the eating and mating cycles, thus stopping eggs from being produced in the first place. The smell of Lavender may also do this, but I think the spot treatment is effective because of a diluted solvent in the liquid rather than the lavender itself.

Yellow sticky traps are doted about to (hopfully) catch the male bugs. Don't forget those too. Every male mealy you catch helps. Maybe a sticky with lavender on it may help?

So far the mealies do seem to be being kept in check, and problem plants are seeming to be sorted once and for all.

[ragamala]

The active ingredient of neem oil is Azadirachtin, one of the systemics in the OP referenced page, which is approved for use in the EU as far as I know until at least 2021. I can't find (other than Neem Oil) any products including this available in the UK.

You can get a lot of stuff on ebay and import it unlawfully, Dave. I hope you aren't advocating that? Frankly the idea that one should avoid regulation designed to protect the environment is not something I would endorse. And from my viewpoint the idea that the UK gold plates regulation deserves a thorough examination. Even if it were true it hardly provides a good reason for Brexit eh? Neem oil itself is not without criticism.

[Chris L]

If you had a tall columnar cacti, and you watered it with a systemic insecticide, where would the most concentration of chemicals end up?

Would they spread evenly along the entire length of the stem or would they be concentrated most at the tip of the stem (i.e. the growing point).

Would it even reach the tip of the stem with enough concentration left to harm mealies?

[ragamala]

Am I wrong, Chris, in thinking systemics would be absorbed through the skin, in which case spraying the entire plant would work, even if the stuff migrated upwards later? Or are you thinking of a root drench?

[Chris L]

Am I wrong, Chris, in thinking systemics would be absorbed through the skin, in which case spraying the entire plant would work, even if the stuff migrated upwards later? Or are you thinking of a root drench?

I've re-read my post and it is a bit vaguely worded. By watering I mean from below.

My understanding of the term "systemic" (i.e. if someone uses the word in a post or talk at a meeting) is that they mean the chemical is taken up by the roots and the term "contact" is used for sprays towards the body of the plant which directly hit the insect.

That is how I would use them.

Can spray be absorbed by the skin of the plant? I suppose it could.

[KarlR]

Avid, which is a miticide, works both on contact and systemically by absorption through the epidermis. But most systemic solutions work by root absorption.

I don't believe cacti are tested much to see how systemics work on them. I'd think systemics work more slowly in cacti, but on the other hand I suppose it's also possible the active ingredient(s) stay longer in the plant body on account of the slower metabolism. On account of their succulent nature, it also seems logical that the active ingredient(s) will spread fairly evenly throughout the plant body. All assumptions though.