Help with Cyrtostachys renda

[AshW]

Hi Guys,

I originally posted about my Cyrtostachys renda a few months ago. They were growing poorly but thanks to the help of this forum, I repotted them and they are performing much better. However, there are still a few things that I was hoping to get some assistance with.

1. One of my palms has developed white spots, but only on a handful of leaves. I have only had this one for about 6 weeks and it is getting worse. Initially, I removed some of the impacted leaves, but it is not on about 20% of the plant.

2. Most of my other palms have these "things" on the underside of the leaves. Having examined them under a microscope, they don't appear to be insects as they don't have legs or wings. Kind of seems like they are growing.

Photos below.

Thanks in advance.

 

 

 

[palmad Merc]

Can you scrape them off?

It looks like some kind of scale.

Edited February 8, 2019 by palmad Merc

[AshW]

The ones in the first photo (white dots) are not scale. The leaves are discoloured.

 

The ones in the second shot can be scraped off. They are only attached at the tops.

Edited February 8, 2019 by AshW

[palmad Merc]

I'd like to know also, as I have the same on some palms!

 

[Merlyn]

The second shot looks like tomentum, a fine hairy fiber that is on the underside on some palm leaves or stems.  If you look at it under a magnifying glass it'll probably look like plain interwoven hairs.  If that's what it is, it is common and nothing to worry about.  Others may know if that palm has noticeable tomentum, but the common pygmy date palm has a similar looking white tomentum on the underside of the leaves, generally along the fold in the leaflet.

The first picture doesn't particularly look like scale or a fungal infestation.  Normally a fungus would end up with brown necrotic spots in the middle with a brown/orange/yellow ring around it.  It's possibly a virus, or maybe damage from spider mites?

[AshW]

It does not seem to be hairy. I spoke to a guy at the local nursery today and he said it was an insect and that I should spray with an insecticide. He recommended systemic however I prefer to avoid chemicals if possible. Have just given them a hit of Castile soap and will see what happens. I have tried using eco-oil in the past but it smothers the leaves.

For the spots, he claimed that they need fertiliser. I am dubious as that seems to be the fallback answer here in Singapore wherever there is a plant problem :-). However, I have been giving them some Thrive soluble for the last few weeks and will add some Osmocote slow release in the next few days.