Date: Wed, 8 Mar 2000 10:17:30 -0800 From: John Brittnacher <britt@epm.ucdavis.edu> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg647$foo@default> Subject: RE: Strange Drosera disease
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.
>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.
John Brittnacher
Davis, California, USA
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