tomato and potato blight

ive been reading a lot on this lately.
lot's of people wondering when to spray with a fungicide{if thats what you use}
As on the packets they say spray at first sign of blight .
and usually in most cases that is already to late.

it takes ninety hours of several prolonged rainy stretches with conditions that farmers refer to as ‘Smith’ periods. This is when the minimum temp is 10º C or higher and at least 11 hours each day when relative humidity is more than 90%.

farmers all over the country know this the huge greenhouse concerns that would probably go bust if an entire crop was to get blight

they spray after 72 hours  of the conditions above  regardless of wether the crop has blight or not

 as spraying to late does not work

 it only takes 90 hours for the spores to get airborn in their millions

Blight Watch - aimed at professional growers, but you may also sign up. You'll get notifications of Smith Periods & "near misses" in your chosen postcode areas.

http://www.potato.org.uk/fab_blightwatch/signup.html

Maps of blight outbreaks here..

Blight

Blight Watch - aimed at professional growers, but you may also sign up. You'll get notifications of Smith Periods & "near misses" in your chosen postcode areas.

http://www.potato.org.uk/fab_blightwatch/signup.html

Maps of blight outbreaks here..

Blight

many thanks for the info it will be very useful