Re: vining peas/ peas and mildew

Allan

I have to challenge your statement that "dryness at the roots is the main
cause of mildew". This could be assumed as unlike most fungi, powdery
mildew spores do not need water for germination. Some species require high
humidity, but the moisture provided at the leaf surface when cold nights
change to warm days or when plants are grown in crowded, low or shady
locations without sufficient air circulation is sufficient to initiate an
epidemic. The most favorable conditions for powdery mildew are nighttime
temperatures of 60oF and relative humidity of 90 to 99%, with 80otemps and
40 to 79% relative humidity during the days -- conditions common in late
spring and early fall. Since the spores are sensitive to extreme heat and
direct sunlight, plants in partial shade are especially vulnerable. It
still comes boils down to, good air circulation is probably your best line
of defense. On Fri, 29 Jan 1999, Allan Day wrote:

Ed

>
> Dryness at the roots is the main cause of mildew, not to be confused
> with moulds. Mulching with compost over moist soil would help, I never
> have enough to go round. A spray over the plants may help as well.
> We always get it on late peas. I have just looked it up and I find a
> recommendation of a spray of 1 level teaspoon of bicarbonate of soda to
> 1 litre (2 pints) of water with a little wetting
> agent.Estimated 95% effective anywhere round the garden(Source:-
> Coventry Polytechnic/HDRA)
> 
> 
> -- 
> 
> Allan Day  Hereford HR2 7AU allan@crwys.demon.co.uk
>
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