Some consideration on Bismarckia

[Phoenikakias]

Latter do not face such trouble, so most probably this topic should be intersting to them.

[Phoenikakias]

[Scot from SC]

Ugh! I am not exactly sure what the name of that pest is, but it appears that he brings nothing but misery! Poor beautiful palm!

[Phoenikakias]

Both are long dead, maybe since a couple of years and were found beneath 7 to 8 layers of old leaf bases! I think sanitation of Bismarckia is very important and not only because of RPW. Certainly a Bismarckia deprived of most of old debris can be more effectively protected through preventive spraying with contact chemicals. But this not the main issue, which remains very discreet in the posted pictures. I mean that Bismarckia concentrates an enormous ammount of moisture under old leaf bases. A moisture that is favored not only by rpw but also by fungi.This may be not an issue in places with low rainfall and spring like temps during winter, because under such conditions accumulated moisture around fresh trunk's part remain low, but in a place with a damp, cloudy and cool to cold winter, it may be most serious trouble. It may also explain why in places of Europe with generally milder winter than in my place but also with more frequent rainfall one can rarely ever or at all encounter a Bismarckia but he can see less cold hardy palms such as Archontophoenix and Caryota.

[Kostas]

Bismarckia do not usually keep dead leafs on them, they only keep 1-3 and shed them fast. I think yours kept the, as an exeption due to the fungal problems it had and staying behind in growth. Normally it wouldn't have kept them, it's a pretty self cleaning palm

[Phoenikakias]

Hmmm, maybe it happens as you describe, when entire leaf (blade, petiole, leaf bot is left on palm still dry until it falls by its own weight and provided that palm has gained a certain height), but a an isolated leaf boot... I doubt so.Old boots detach easily but the lst two or three ones as you said, but some human help is needed.

[gyuseppe]

Konstantinos not is species of weevil?

(not rhynchophorus ferrugineus)

[Phoenikakias]

yes Giuseppe, it's the punteruolo rosso (two of them) but dead since a a couple of years.

[richnorm]

Looks to be growing out of its problems. Here they die from the centre outwards but I must say I have planted five Bismarckia and so far had no losses in my cool damp climate. The problem seems to be lack of air flow arising when they get too crowded by other plantings. Here they really need space all around them and maximum sun. I have learned the hard way not to remove old leaf bases too soon!

[Phoenikakias]

Agree Richard,, and when Bizzie plus other palms grow eventually bigger, situation may get crowded...

[Kostas]

Yes, i mean when the whole leaf is left on. Leaf bases don't have enough weight to be shed on their own. And of course the trunk needs to be tall enough for the leaf to hang, otherwise its more difficult, but whole leafs are generally shed easier than leaf boots.

When the palm is young, i agree that some gentle manual help is inevitably needed, especially since we can't always leave the whole dead leaf on then. But its important not to rush them either

Giuseppe,

Those dead weevils do are Rhynchophorus ferrugineus. Individuals that are long dead get this uniform darker color through oxidation of the coloring substances of the exoskeleton.

[Phoenikakias]

Are you a bug expert?!

[Kostas]

I have worked at the National Forest Research Institute, at the entomology lab, and done research on Rhychophorus ferrugineous, it's biology, ways of attraction to palms and ways to protect/treat the palms. I already had some knowledge on entomology prior to that but I worked greatly on it during my work at the entomology lab with the help of a great entomologist, Dr. Petrakis, who runs the lab