Saturday, August 19, 2006

Saturday 19th August - Marrow Trouble

There is a white powdery substance over 80% of the marrow leaves. It appeared overnight and I suspect it is something bad.

10 comments:

Greenmantle said...

It's "Powdery Mildew".

It's a common disease on marrows and courgettes towards this time of year, and usually signals the beginning of the end, as the season draws to close.

The plants will carry on for a good while yet, but the mildew will increase as the evenings get colder and damper.

You can spay against it, and help by removing the worst affected leaves.

Check this:

http://ipm.uiuc.edu/diseases/series900/rpd925/index.html

Frankie said...

Oh Pooh!

Petunia's Gardener said...

Its starting to show on my zucchini too. They don't have the room they should have so I may try thinning leaves a little and the milk or baking soda recipes below (not tried before, though), before buying a spray.

From Organic Gardening website: Prevention also includes siting plants where they will have good air circulation, and exposing as much leaf surface as possible to direct sunlight, which inhibits spore germination.
To control minor infestations, pick off affected plant parts and either compost them in a hot compost pile or bag them tightly and put them in the trash. Research studies in 1999 and 2003 on infected zucchini indicated that spraying cow's milk slowed the spread of the disease. To try this at home, mix 1 part milk with 9 parts water and spray the stems and tops of leaves with the solution. Reapply after rain. Spraying leaves with baking soda (1 teaspoon in 1 quart water) raises the pH, creating an inhospitable environment for powdery mildew.

Greenmantle said...

That's what I like about this blogging maullarkey....you get a really clever homespun solution nine times out of ten...Thanks for the baking soda tip PG !

Frankie said...

BRILLIANT!

Thanks Petunia, I have removed the worst leaves and will get up there tonight with some milk and baking soda.

Anonymous said...

I've had this problem also but never treated it - mostly because we were getting tired of what to do with more courgettes. Anyway as greenmantle says it usually signals the beginning of the end.
Well it better as I've got to use up eight pounds of the b*****s this week.

The Gnome said...

Well I must be doing something right because for the second year running the courgettes and marrows on my plot are rampant and healthy. This weekend I shall be experimenting with a marrow expansion technique as taught by my Grandfather. But it will not involve cows milk and soda, more like sugar water for the marrow and a bottle of beer for me when I get home.

Frankie said...

The beer sounds good to me!

Anonymous said...

It's me! Sorry.
It's rampent on my melons too. (that somehow sounds wrong...)

Liking the milk and baking soda solutions a lot, I'm off to the corner shop in just a tic to get the soda now, thanks Petunia!

Petunia's Gardener said...

Aghhh... found spots on assorted host plants today. Our weather has just been ideal for it, unfortunately. Haven't tried the milk yet. I think the baking soda & water seems to slow it down some. I suspect it won't cure it by any means. Think my solution was a little stronger than the recipe above. Today, I also thinned out some leaves to help with air. I can live with fewer zucchini, but I don't want my pumpkin vines to go before the pumpkins are done enough.