White on Courgette leaf....

[SusieG]

What is this 'white' on my courgette leaf.....and is it detrimental to it ....?
Thanks!

[roitelet]

Looks like a bit of powdery mildew. You could spray with a milk solution one part semi skimmed milk two parts water.

[Chris11]

Agreed, looks like powdery mildew, my courgettes get it most years.
It's very common with the cucurbits.

RHS info here:
https://www.rhs.org.uk/advice/Profile?pid=253

[Bigmallly]

Nowt to worry about Susie, if you don't want to treat it just cut the leaf off.

[SusieG]

Ah, thanks BM, that was going to be my next question ....!
Is it best not to compost the affected leaves...?

It does seem to have taken hold on almost every leaf of this one plant - do I whip off all the affected leaves....? Or should I do the milk/water spray if it's affected so much of the plant...?

[Bigmallly]

I wouldn't remove them all as I believe leaves are needed to aid the plants growth through Photosynthesis but am not fully clued up how it works.

[SusieG]

Looks like a bit of powdery mildew. You could spray with a milk solution one part semi skimmed milk two parts water.

Ok roitelet - have cut off one or two leaves, and the rest I've given a good spray with your suggested milk solution .........

I only had skimmed milk though - do you think it'll still be effective (I made the solution with a spot more milk to make up!!). DH thinks I'm mad ..... And says all the local cats will be around licking the milk spray off the leaves....... I said that's that how it works...cats lick the milk and the mildew off the leaves while doing so - problem solved!!!

[MarkPelican]

A cause of Powdery Mildew is stress due to lack of water and a suggested help is to mulch around the base of the plant to help prevent water loss.

[Penellype]

That's what I thought. Usually my pot grown plants suffer first because they are more exposed to wind and drying out. But this year I planted courgettes in my cold frame, protected from the wind and in the soil, which is a moist part of the garden, and they have mildew. I planted a spare one in a pot about 5 feet away, with little protection, and guess what? No mildew (yet)!

[Bigmallly]

I'nt gardening a funny game?........................

[cariann88]

I have some white in the veins on the courgette leafs but when I have ran my finger over it nothing has come off. Could it still be powder mildew?

[LexLucre]

I have a couple of large courgette plants that powdery mildew seems to have taken a large hold on.

No experience to add, but I removed the lower leaves that were badly effected and looked like they'd basically died anyway. I've just sprayed them with the "SB Plant Invigorator" mentioned on that RHS page but I'm not optimistic, it seems suitably vague as to what it actually is, and purports to be a panacea of all manner of problems.

The plants are absolutely loaded with courgettes that will mature in a few days so I'm interested to see whether the plants are strong enough to continue regardless or whether they're on their last legs.

I'll report back if the plant invigorator miraculously does anything.

[SusieG]

I'nt gardening a funny game?........................

Sure is BM ~ guess that's what makes it so interesting/enjoyable.......!!

Cariann - my other courgette planted out just 1ft away from the affected one is totally fine (so far!!!) ...

[SusieG]

LexLucre - this powdery mildew stuff doesn't seem to have affected the production of fruits on my plant .... Just have to see how it goes .... your SB Plant Invigorator versus my milk/water spray .......!

Watch this space.......!!!!

[Penellype]

I find that the plants will continue to produce courgettes at first, although they don't mature as fast or get as big as usual. As the disease takes hold the plant gets weaker and the courgettes themselves can be affected by the mildew. Eventually the baby courgettes simply shrivel and fall off.

I haven't tried spraying with anything so I can't comment on how effective it is. I have tried cutting leaves off and I think it may slow down the spread if you catch it early enough, but there is a limit to how much you can cut off before you damage the plant anyway, and once a plant is affected my experience is it always comes back fairly quickly.