Re: Green spots on plants

> From: Stanley Liu <stanley.liu at amgen_com>
> I was wondering if anyone could help identify these strange round, green
> spots that have started growing on my plants (namely on the hygro).  
> They are generally 2-3 mm 
> in diameter, and are a deep green colour.  Is this a type of strange
> green algae, or could this be a plant infection of some sort?  I have
> two S.A.Es, but they seem to have no effect on removing these strange
> spots.  Any plant leaves that have these green spots on them curl up and 
> eventually die off.  

You didn't say which kind of Hygrophilia you are growing. Both H. 
difformis and H. polysperma will exhibit yellowing and algae attacks
on lower, older leaves. The algae seems to attack a weakened leaf
which indicates a symptom of being weak rather than the cause. The
green spots are an algae; the types of algae present depend mainly
upon the types which have been introduced being present on plants
which you purchased. Is the algae soft, somewhat slimey and easily
removed with your fingers, slightly blue-green in color? or is it
a harder, thin round spot. You can check out the plant FAQ for
descriptions of algae types and treatments.

You can really improve the health and long term viability of the
Hygrophilas by increasing lighting, providing about 15ppm of CO2,
supplementing with good quality micro-nutrients like Flourish or
Dupla or Tropica and by providing a good substrate. Beware of algae
problems when increasing lighting; I have not had a chance to put
Paul Krombholz's algae free regimen into effect but I must say that
it sounds extremely promising. You can also cut off the tops of
those stem plants with algae, discarding the affected bottoms and
replanting the tops. Be patient, this will pay off. The yellowing
and weakening of lower leaves is very common with these fast growing
types of plants.