Date: Fri, 31 Mar 2000 21:28:09 +0200 From: strega@split.it (Tassara) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg957$foo@default> Subject: Re: R: Strange Drosera disease
Hi John,
thanks for your reply.
Today I've examined under a microscope some leaves of D. callistos, D.
peltata and D. stolonifera and I've found no filaments.
The tentacles curl in the same manner as those of the plant in your picture,
but to a greater extent and in some plants all the tentacles of all the
leaves are curled. A very sad sight!
The tentacles are shrivelled and their tip is dry.
With the microscope I've noted a few small objects attached to some of them:
they are whitish and when they are fully developed they resemble a pair of
not completely opened mushrooms.
On the other side, I've noted no animals (mites or anything else) so I
assume it is a fungal illness.
Identifying a fungus seems to be very hard, so I assume I should try many
fungicides hoping I'll find one which works.
I fear tuberous and especially pigmy sundews can't survive after loosing all
their leaves, so I'll use sulfur just as a last chance.
Regards
Filippo
Filippo Tassara wrote:
>>I've recently noted on some sundew leaves a strange illness: in a few days
all >>the tentacles of all the leaves (young and old) of some plants curl
completely >>towards the center of the leaf, not in the normal way, but
forming a >>semi-circle.
>>This happened on D. peltata, D. cistiflora, D. glabripes, D. stolonifera,
D. >>menziesii and D. callistos.
>>The leaves didn't catch any prey and I didn't spray anything over them.
>>I've examined them under a microscope because I suspected small parasites
could >>be involved, but I found none.
>>The curled tentacles are rether deformed and their tip lacks mucilage.
>>The plants, apart from the tentacles, look healthy.
>>Does anybody know what could it be?
John Brittnacher wrote:
>I have seen this too and even did a web page on it. The page is
>under Pests at http://www-epm.ucdavis.edu/~britt/CPs.htm. However I
>don't know what causes the problem. If it is mites I can't find them
>or evidence of "bites" either. If it is a fungus all I find is a
>filamentary fungus.
>
>The last time I saw it before a few weeks ago was last spring. Last
>year I thought I could figure out what it was from what keeps it from
>spreading. Orthene (insecticide), Kelthane (miticide and general
>nuker), Captan (fungicide), and a systemic fungicide that is
>supposedly a replacement for benomyl aren't effective. The only
>thing I know of that helps is sulfur. I use sulfur to treat it but
>don't know if it would actually go away by itself. That sulfur helps
>isn't much of a hint. Nothing will reverse the damage.
>
>I am beginning to think it is a fungus that spreads during the winter
>when things are cool and only shows an effect when it warms up in the
>spring. If I see a general outbreak this year with enough plants to
>do a proper experiment I will ask our pest person to try some of the
>more exotic systemic fungicides that normal humans can't buy here.
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