Yellow streaks and blotches

[Carlo Morici]

During the next weeks, hopefully, specialists will go throught the phytosanitary problems in the Palmetum in Tenerife. All I can tell is which palm looks sick, as I am very basic in pests, diseases, deficiencies, etc. I am worried about streaks like these in some palms at the palmetum, both in the nursery and in the field, often on Coccothrinax, Areca (and Pritchardia, Corypha, Copernicia...). I wish I had more pictures, but here are some. Any opnions?

Coccothrinax

[Carlo Morici]

Areca

[Tyrone]

I think you may have a fungus or a virus at work. On the last pic I couldn't tell if there were rasping indentations there which would indicate insect predation or whether they were smoothish indicating something happening from the inside. Can you tell me if they are rasping marks?

Best regards

Tyrone

[Carlo Morici]

Tyrone, the dark spots in the last pic is tissue burned by sunlight or wind/cold. Those spots/strikes were chlorotic and burned afterwards. Other Areca macrocalyx growing by show no damage.

I know so little about this. I don't even know if we are dealing with just one problem or many. I was also thinking of nutritional problems or virus. There are lots of white flies around, known to spread "viruses". Some of the yellow strikings stay for years or forever. One C.baileyana is yellowish since it was planted 10 years ago and it stayed smaller than its neighbouring plants, so a Corypha utan. In various Coccothrinax species, it seems to follow bad conditions (drought, too wet, underpotting...) and also it stays for months or years. It goes back in summer and comes back in winter... it looks like they try to "grow through it" when the weather allows.

I have found some more pictures of Pritchardia remota.... some called it variegation?!

[Davidl]

My guess is its a nutritional problem and there could be other factors as well. Many palms in fl do this when it gets cool and disappears in the summer.

[cfkingfish]

IRON

[Keith N Tampa (ex SoJax)]

Carlo, the photos of the Cocothrinax leaf looks identical to mine here in North FL. I thought it was a response to cold weather, possibly even frost (a frequent visitor this winter). Though it's possible you have viral infections, the symptoms are usually transient. During hot weather, the symptoms disappear only to reappear once it cools. Viruses rarely kill plants, but they do slow growth and reduce productivity on economic crops. The photos of injury on the Areca clearly look like frost to me. Though I don't have anything in genus Areca, I've seen similar symptoms on tropicals like Ptycosperma, Vetchia, and Adonidia. Is it possible you may have had some frost formation? In the right conditions frost will form a few degrees C above the freezing point. I'm less clear about the symptoms on the Pritchardia. I have Washingtonia with similar symptoms, but I've allways attributed them to Potassium deficiency. The most important difference between your image and my palms is that the younger leaves of my Washingtonia look normal. In your photo, all the leaves seem affected, and the newly opend frond appears light green. I realize that might be because it's cool this time of year and the frond might be very young which might explain the color difference. However, I still suspect a nutrient imbalance, probably a micronutrient. Christain says iron, and that might be correct, but the symptoms are not classic Iron deficiency. Of course, who knows what classic iron deficiency symptoms are on Pritchardia remota! Christain may have grown them, he certainly has the right experience. Can you tell me the pH of the soil there? Do you have a soil test? If not, can you get one? Do you have a readily available source of Iron, preferably chelated. I suspect your soil pH is high and the chelated form (best form is Iron EDDHA, not EDTA). You can treat the plant and see if it recovers, but one word of caution: if it's not iron but, (for example) Manganese, there is a chance the plant will get worse, not better.

[edric]

Where are the specimens located, how do you apply water, Ed

[Carlo Morici]

David, Christian. It could be a nutritional problem for the Coccothrinax spp. because they stayed in the same pots for some years (But I saw good plants in good soils getting streaked for years after a defoliating drought). I don't think it is nutritional for the Pricthardia, as they should thrive like crazy where they are. The discussed Copernicia, Areca and Corypha are planted side-by-side to healthy plants, planted in rich soils irrigated with depured water, so nutritional problems are improbable. I thought of viruses, as the winter-summer cylce reminds me what I often see in papaya trees affected by a virus of mosaic chlorosis.

Keith, we have no frost at all. These palms have never experienced anything below +10 C (in the nursery) or +14 C (in the Palmetum). Chlorotic-variegated tissue burns well above the critical point for the regular species. The leaf tips of the variegated Phoenix canariensis burn in the wind even if never below +10 C, even if in the Canaries. I have no recent soil test. Soil is slightly basic, but... yellowing in Pritchardia?, here? I just see yellowing in famous "acid" species, like Beccariophoenix, Licuala, Chuniophoenix, Calyptro...

Please tell me more and more suggestions. We can do whatever we want, as the Agriculture Research Centre backs us.... soil test, foliar analysis, hopefully virus tests... Today I visited again, but I did not take any new pictures. I would love to show the C.baileyana.

Carlo

[Carlo Morici]

Ed, the Coccothrinax and Areca are grown in pots in the public nurseries of the municipality of Santa Cruz. The Pritchardia (and many others mentioned) are planted in the ground in the Palmetum de Santa Cruz, all in Tenerife, Canary Islands.

[Jeff Searle]

Lots of us can offer suggestions. I will suggest one IMPORTANT one, if you have access to a lab that can send someone out to take samples of leaves and the soil, do it. They will tell you EXACTLY whats going on and what to do to treat the problem. You can start spraying fungicides, minor elements, throw some fertilizer down,etc. but you all your doing is guessing.

Save yourself alot of time and money.......

Jeff

[Keith N Tampa (ex SoJax)]

Carlo, here is a link that might help with the nutrient deficiencies of palms. Dr Broschat also co-authored (with Alan Meerow) a great book on palm culture: Ornamental Palm Horticulture published by University Press of Florida.

http://edis.ifas.ufl.edu/pdffiles/EP/EP26900.pdf

Hope this helps, even if not with the problems you've identified in this thread

[rozpalm]

Carlo I have a small Cocothrimax gundlachii that looks exactly like the picture in your first post. I assumed it was nutritional since its been in the same pot for possibly 6 years or more. I was hoping once I put it in the ground that it will go away.

[Carlo Morici]

Jeff, yes, we will ask some lab analysis.

Keith, thank you for the link, I will read a bit. I seldom see nutritional disorders here as the island is volcanic and most soils are very fertile.

Rozpalm, 6 years in the same pot is too much. Coccothrinax should be transplanted every 1-3 years. When I planted streaked Coccothrinax in the ground, I got lots of bad results. Some were very weak, they got fungi and died - it never happened on healthy non-streaked specimens!, some others are going ahead, very slowly, hopefully recovering.

Carlo