Pest or disease?

[quaman58]

Hey all,

I previously posted some images about this issue I have on Phoenix robellini. There are 4 plants affected & it is getting worse. These plants are probably 12 years old at a minimum. The crowns are sparse, there are numerous unopened fronds. At first glance it looks like an awful scale infection. But upon close inspection it does not appear to be scale. There's a gritty, coarse residue that covers the new fronds as they emerge. I simply can't see anything alive in it. The leaves and petioles develope a brown/ orange spotting. I'm pretty sure it will ultimately be fatal. I know that Phoenix are "a dime a dozen" type of palm, but obviously having an unexplained malady in the garden is a very bad thing. Someone has to have seen this before. Any thoughts? I've treated with sprays for pest control, even went with malation which seems to kill every insect I know of. Not whatever this is.

A few pics:

Thanks in advance,

Bret

[garrin]

Both from my observation and experience with these things in my own garden, I would suggest that you have a bad mealy bug or scale insect infestation. If you have used insecticides for this without result it could be some kind of scale

insect which are impervious to most topical insecticides. For these, systemic insecticides will work, perhaps after a few applications. You won't notice much difference in the appearance because the scales will remain in place after they die. But before long a good strong hosing will wash the dead shells right off. I hope this is a good suggestion as there could be other causes of which I am not aware. But I certainly believe what I have proposed.

Garrin

[Jeff in Costa Rica]

Bret, If it is scale - I've heard that horticultural oil will do the trick. It apparently suffocates the scale.

[LJG]

I had this same thing hit my PR's two years ago. I mean it hit all. At that stage I had about 20. No idea what it was. The ones I knew I was ripping out as my palm bug grew I left alone. They eventfully die from this. The ones I knew I wanted to keep I hit with Malathion and also fungicide. I did this weekly. It finally went away and a new healthy flushes have followed. I assume it is some type of scale that hits Phoenix robellinis. Because I have never seen it on any other plant. But to be safe I was using Daconil too.

[Perito]

Some mites are very hard to see and don't necesarily leave the telltale threads common with mites. I'd try an oil like jla suggested.

I like Saf-t-side. It suffocates the eggs as well as killing the adults. Perito

[Phil]

Bret,

A key to diagnosing insect problems is to look at and ID the insect. Get a really strong magnifying glass and look at the diseased areas. To you see bugs? Is anything moving, even if just a tiny bit. Scale are little dome shaped things and don't move much. They flick off with a knife. Mealy bug are like little splotches of cotton candy. With magnification, you'll see body parts and antennas or legs. Mites are microscopic spiders. All of these can be "removed". If fungal, you may see something akin to mold or patterns, but its hallmark is diseased leaves. In terms of treatment, I'd first blast all the leaves and crown with high pressure water to clean off debri. I'd then treat with both fungicide and an insecticide at weekly intervals if you can't specifically ID the malady. Use protective gear. Then wait to see if it improves.

Phil

[quaman58]

Thanks all for your replies. The common theme seems to be physical removal, and regular applications of insecticides/ fungicides. I think Len also brings up a good point of hitting them frequently. I've not done this, but I will now. As a point of interest, this began on one palm following the stress of the 2007 freeze. Since they're overhead, it took me months to figure out that something was indeed wrong; that it wasn't just freeze damage they'd grow out of. Thanks again!

Bret.

[LJG]

Bret, that is interesting and I never paid attention that, but that is when mine hit - right after the 2007 freeze. I said it was about two years ago when I noticed it. Maybe they got really stressed to allow this stuff to move in. I know it can be a killer. Once I beat it back, the plants have been healthy.

Thanks all for your replies. The common theme seems to be physical removal, and regular applications of insecticides/ fungicides. I think Len also brings up a good point of hitting them frequently. I've not done this, but I will now. As a point of interest, this began on one palm following the stress of the 2007 freeze. Since they're overhead, it took me months to figure out that something was indeed wrong; that it wasn't just freeze damage they'd grow out of. Thanks again!

Bret.

[LJG]

I seriously need to get with it. I still spray Malathion, Miticide, Fungicides, etc with no protection. Even in the greenhouse.

Use protective gear.

[Joe palma]

Brett, Len,

Does this lead to crown lean/tilt??

I noticed a month or so ago 4 robos that have their crown leaning over.

I see no bugs/fungus or other forms of distress, but the new spears are leaning to one side, w/ the trunk staying were it was at.

I have read that boron defficiencies can lead to these types of issues but I also know that we have plenty of boron in our soils (so I have been told, no testing done). It is happening on my biggest one that has about 5 feet of clear trunk.

Anybody know whether this is related or something else?

I'll take a closer look to see if there is something I have missed.

Here are two pics (sorry no the greatest).

Joe

[edric]

Your not getting the crown wet, when you water, are you, Ed

[LJG]

Hey Joe, that is the first sign I noticed. Mine are not tall like Bret's so I bet he did not see the warning. Left unchecked, it goes to the stage you see in Bret's. Like I said, I got rid of mine by hitting it weekly with Malathion and Daconil. This took some time. No idea if one or the other worked as I did both sprayings.

[Mark_NoVA]

I had something similar a couple of years ago and let it get out of control--looked like a giant cottony mess (much more white fluffy stuff than in your photo). I tried a few different things and the plant survived but looked awful, and so it didn't make the cut for plants that get brought inside this year.

[Gonzer]

I use a diluted surfactant spray such as Water-In® for problems like this. It dries up the waxy coating shielding the bugs and is a heckuva lot safer than pesticides. Depending on the insect problem and % of dilution, surfactant spray is all I've used for years. Good stuff!