Mould on Yucca

[Cetti]

The floor surrounding the plant has been covered in black spots for a couple of weeks and I put it down to a leaky roof, but today I noticed mould on the lower leaves accompanied by sticky water droplets. Does anyone know if this is serious or not? Thank you for any help.

[Thunderbird+]

Hi Cetti, I'm thinking it might be due to a sap sucking insect like 'red spider mite' they are tiny and difficult to see, sometimes noticed by fine webbing on the underside of leaves. Mould will grow on the 'Honeydew' that they poo out of their rear ends.

If it is them, they can be treated with a houseplant insecticide containing permethrinor pyretthrum.
Good Luck Tbird+

[Cetti]

Yes Tbird, there is a tiny bit of webbing on the very bottom of the plant.
This is where the black spots are at their thickest, but droplets are now appearing on the top of the plant, so do I try and wipe it off or just spray?
Is there any particular name spray or anyone with the ingredients you mentioned?

[Thunderbird+]

Hi there again Cetti, Aha' just as I expected! them little blighters are very common at this time of year, when we reduce watering and turn up the heating, thus giving them the ideal condition to breed like crazy!

Re the honey dew droplets, I would feel inclined to dab them off with a tisue, rather than try to wipe them off, otherwise it might smear and spread the mould.

I'm not sure if any of the prepriety sprays are better than others but I think it would be wise to choose a well known brand ( i hope you noticed todays deliberate mistake when I missed the gap at the end of Permethrin.)
Hope someone can recomend a spray that works well for them!
A good tip to keep the R S M's at bay, once you have them under control is to spray regularly with water, as they hate getting wet. All the best. Tbird+

[Cetti]

Thank you so much Tbird....you're an angel!

No, I didn't have a clue about the name. I've actually written down permethrinor... and would have argued in the shop that it was correct :-)

[hortus]

Try Bug Gun. You can get it from any garden centre.
Have you noticed any little tiny white flakes on the leaves. If you do see any, they are scale insects and could be to blame.

[Cetti]

Hello hortus! Yes, I sprayed with Bug Gun this morning - and yes again - the bottom of the plant is covered with white fragments that I imagined was white fly.

Will my poor plant recover from this, I wonder? Tbird has identified the cause of the sticky droplets with webbing and now you have said it is scale insects. Poor plant, it's only a few months old as well! Thank you both for your help.

One more thing - How often should I spray and will the scale/white fly fall off, or should I attempt to clean the leaves?

[esti-sutree]

Hi, we have some videos about gardening which I think may help you.
you can see them here:
http://www.sutree.com/videos/garden/125

Hope it will help you :)
Esti from sutree.com

[Cetti]

Thank you, they will be very helpful.