Re: Plant Disease ?

>Some of my plants (Hygrophila difformis and Hygrophila stricta)
>start developing the following disease. The plant leaves are still green but
>there are quite a few small yellow dots with black centers on them. 
>After a while, the black dot gets larger and leaves a hole in the middle.
>Any idea what kind of disease is this ? All of the other plants in the tank
>(Ludwigia, water sprite, bacopa, anubias, riccia fluitans, rotala 
>are doing great.

I had a problem with the same description with some hygrophila that I tried to 
grow a few years ago.  They grew like gangbusters for a while, although they 
were kind of greenish-yellow (due to way too little light).  After a while, 
they started slowing down and developing spots.  Then, they started to die 
back.  I had no snails.  

At that time, my tank parameters were *very* poor:
pH:            about 6.5
KH:            close to nothing, although I didn't have any test kits then.
nitrates:      > 100 ppm
water changes: very infrequent, about 5 gal every month or so

I don't know what the disease was.

Since then, I've gone from 30 watts to 80 watts and will someday complete my 
180 watt free-standing hood (hopefully soon).  I now have hygrophila again.  
They're still kind of yellow (IMO), and they're growing fast.  All of my other 
plants are doing wonderfully.

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc.
(214) 575-3443 (voice)		MSGID:		DAWB
(214) 575-4853 (fax)		Internet:	dwebb at ti_com
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