Need help identifying this disease/pest

jcb954January 29, 2013

I have a mature Phoenix Robellini (Pigmy Date Palm) in the front of my house where it gets full sun. I had a cluster of 2 and the one died a few years ago with a white powder. This one that stayed alive has had a very strange brown crusty substance on the underside of the leaves that makes it hard for new fronds to open up properly. This substance covers all the leaves. It gets proper fertalizer so I doubt its a deficiency. My landscaper cannot figure out what it is either. There ants that crawl all over the plant, but not sure if that is related to the problem or not. I would appreciate any help from someone who thinks they know what this is.

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jcb954

Here is another zoomed out picture of the same tree.

    Bookmark   January 29, 2013 at 2:58PM
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rhizo_1 (North AL) zone 7

Since you can see the problem up close and we can't, you'll have to be a detective. It looks like you have a scale insect infestation going on, perhaps the Red Date Scale that is causing problems in some locations. I wish I could see a good closeup.

Look up the red date scale so you can compare some photographs with what you see. It could also be any of a number of other scale species. Ants, by the way are often found where there is a scale problem...they feed on the sugary excrement made by the scale.

    Bookmark   January 29, 2013 at 3:48PM
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jcb954

Thanks Rhizo, I think you hit the nail on the head with this one. I looked up Red Date Scale and the pictures and descriptions look almost identical to what I have. I also found a website that says there is an outbreak in Palm Beach County, which is where I live. They say I need to use imidacloprid and perhaps frequent spraying of oil soap. They also said it happens more frequely with pigmy date palms that are in the shade and come to think of it, there are 3 larger palms above it and maybe it is in more shade than full sun afterall. I think I'm going to go with this...thanks for solving my mystery!!

    Bookmark   January 29, 2013 at 4:07PM
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rhizo_1 (North AL) zone 7

Bingo!

    Bookmark   January 29, 2013 at 5:29PM
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ken_adrian Adrian MI cold Z5

My landscaper cannot figure out what it is either. There ants that crawl all over the plant, but not sure if that is related to the problem or not.

==>>

one might suggest you need a more learned landscaper ...

ants milk scale for honeydew.. ignore them ... when the scale goes away.. the ants will go find something else ...

i surely have no personal experience with palm.. but doesnt that thing need a trimming up .... and isnt it a bit close to the house???? [maybe its a trick of the camera angle ...]

finally.. you said: It gets proper fertilizer so I doubt its a deficiency

i hope you arent doing too much in that regard ... especially if you are paying your landscaper to do so ... a better question might be.. if a palm actually needs fert ... but alas.. i dont know ...

and i dont know if i would rely on him.. to take care of something he is not familiar with ... you might want to make some calls to real professionals .... you are probably looking for an application or two of horticultural oil [precise timing is imperative] .. that i would suggest.. not be sprayed on the house .... or a systemic if that is a viable option with palm

ken

    Bookmark   January 30, 2013 at 7:57AM
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jcb954

@ken Agreed, I would expect a good landscaper would be able to diagnose pretty much anything, but he cuts my grass very well for cheap so I'm keeping him. I do all the fertalizing myself and I fertalize my palms (and yes they need fertalizer if you want them to look great) as well as everything else which has created a very lush look on my property. Perhaps I will trim my palm up when its a bit more healthy. I have emailed a master gardener in the area and asked him to recommend a place where I can buy imidacloprid root drench which I think is my best choice now. Home Depot doesn't carry this...only the spray which I doubt will be strong enough.

    Bookmark   January 30, 2013 at 1:02PM
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rhizo_1 (North AL) zone 7

jcb, I'd advise you to NOT limb your palm up! Most people, including landscapers do not understand that the newest leaves are the least efficient for the plant. The older (lower) ones do most of the work. By all means trim any dead fronds, but palms should be allowed to carry a full complement of fronds. Be sure that the landscaper doesn't do it without your permission.

Ken, palms have unique micronutrient requirements.

    Bookmark   January 30, 2013 at 4:40PM
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jcb954

@rhizo Yes, I am very aware of this fact about palm trees. The dying limbs send vital nutrients to the plant. Some people get obsessive with cutting all of the lower limbs off as soon as they start looking a little aged and it will actually starve the plant over time. Thanks for pointing this out!

    Bookmark   January 30, 2013 at 5:24PM
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rhizo_1 (North AL) zone 7

Yay! You are one of the few people who understand how palms work.

I think that if I were you, I'd give the local extension office a visit or call. They should be on top of what, when, and how to tackle this very pesky pest.

Good luck to you.

    Bookmark   January 31, 2013 at 3:47AM
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ken_adrian Adrian MI cold Z5

but he cuts my grass very well for cheap so I'm keeping him.

==>>> OK.. you have a GRASS CUTTER.. not a landscaper..

and that is quite apparent ...

if this thing is precious to you.. hire the right guy for the job ... [which might vastly destroy your lawn cutting savings.. lol ...]

i admitted no palm experience.. and since many grow in sand .. i suspected it might be from a world of its own ...

imidacloprid ==>> look for Bayer tree and shrub products ... you arent going to buy it straight under that name ... at bigboxstore ... and most likely nowhere REPUTABLE.. w/o a license

INSURE it is labeled for said use ... apply it according to the label ... and dont mess around with it ...

i never understood spraying of a systemic.. think about it.. the roots are the most efficient sucker inner [technical term there] .. so why not use them so suck it up .. besides the fact.. that spraying a plant that size is just going to waft stuff all over you.. the house.. and half way down the block.. be safe ...

ken

BTW.. most scale.. being that they are scaly .. get this.. are impervious to topside applications ... you have to get the product into the vital juices of the plants .. [not through the scale cover of the little sucker ... the only reason oil works on scale.. is it suffocates them.. ] .. and the best way to do that.. is thru the roots ...

Here is a link that might be useful: link

    Bookmark   January 31, 2013 at 10:22AM
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