Re: Help (needed in Greece)
"Sean A. O'Hara" wrote:
>
> At 11:11 AM 6/11/00 -0400, Martin Jones wrote:
> >>Spraying the grapes against mildew so far has been restriced to benomyl,
> Is there anything better or more environmentally acceptable? Bordeaux
> mixture is less acceptable (more messy) as one must clear away all terrace
> furniture before spraying.
> Many thanks for any comments, Martin Jones.<<
>
> I understand that it is the European races of grapes that have mildew
> problems, American races being immune. Sulfur dust is usually suggested
> here, an application when the shoots are about 6in (15cm) and then every
> two weeks. The cause of your mildew might be overhead watering from a lawn
> or adjacent garden, poor air circulation, or too much shade (full blazing
> sun rarely sees mildew when the foliage is kept dry). Correcting these
> problems (if possible) might help prevent mildew without the dusting or
> spraying.
Hi Sean and Martin
Sean is correct that sulphur is the fungicide for powdery mildew. It can
be had either as a dust or in a sprayable form.
If you want to avoid much mess however why not try the home-made bicarb
spray for powdery mildew?
This is made by adding 1 teaspoon of sodium bicarbonate and 1 teaspoon
cooking oil per litre of water. You will also need a couple of drops of
detergent to disperse the oil. Shake or stir and apply undiluted.
(Note, the penetration of any fungicide on the powdery mildew will be
greatly improved if the loose mass of spores on the surface is hosed off
just before spraying.)
Bordeaux mixture (based on copper) has no effect on this fungus, though
it can be used for the very different downy mildew. In any case Bordeaux
is pretty well obsolete. If one needs a copper spray Copper Hydroxide
(sometimes known as "Kocide") would be my fungicide of choice, being
very simple to apply.
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata, New Zealand. (on the "Ring of Fire" in the SW Pacific).
Lat. 41:16S Long. 174:58E. Climate: Mediterranean/Temperate
