aarnswife
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Brown spots on Basil Plant

I am new to gardening, this is my first year. I have a very large Basil plant but the lower leaves have developed brown spots pretty recently. Can someone tell me what they are?
ImageImage

TIA!

n8young
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Joined: Wed May 01, 2013 3:39 pm
Location: Eliot, ME - zone 6a

Re: Brown spots on Basil Plant

is it getting cold at night where you live? Mine always ends up turning brown when it gets too cold. Not sure if that's the cause or not, but mine always starts to look like your pictures towards the end of every garden season. I usually just yank the whole plant soon, and hang it to dry. All it takes is one real cold night(I Don't even think it has to be belowing freezing) and your basil can be toast.

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rainbowgardener
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Location: TN/GA 7b

Re: Brown spots on Basil Plant

Well, the old leaves at the bottom are dying anyway, so they are vulnerable. It looks like some kind of fungal disease.

My concern would be whether or not it might be basil downy mildew, which would be very bad news. To me, it isn't looking just like it, but I'm not sure. Check the under sides of all the leaves that have marks on them. The under side of leaves attacked by the downy mildew will look like this:

Image

little dark dots that are only between the veins and are slightly fuzzy. This is the spores of the mildew.

If it looks like that, you probably might as well destroy all the affected plants to keep it from spreading. It is one of the really nasty ones. If there is no sporulation, then I would just pull off and trash (not compost) all the leaves with marks and then just keep an eye out and see what happens. Don't over water and don't water the leaves (only the soil).
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aarnswife
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Joined: Thu Sep 08, 2016 10:39 pm

Re: Brown spots on Basil Plant

n8young wrote:is it getting cold at night where you live? Mine always ends up turning brown when it gets too cold. Not sure if that's the cause or not, but mine always starts to look like your pictures towards the end of every garden season. I usually just yank the whole plant soon, and hang it to dry. All it takes is one real cold night(I Don't even think it has to be belowing freezing) and your basil can be toast.

No, it's about 70 - 80 something at night - I am in Texas,

aarnswife
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Joined: Thu Sep 08, 2016 10:39 pm

Re: Brown spots on Basil Plant

rainbowgardener wrote:Well, the old leaves at the bottom are dying anyway, so they are vulnerable. It looks like some kind of fungal disease.

My concern would be whether or not it might be basil downy mildew, which would be very bad news. To me, it isn't looking just like it, but I'm not sure. Check the under sides of all the leaves that have marks on them. The under side of leaves attacked by the downy mildew will look like this:

Image

little dark dots that are only between the veins and are slightly fuzzy. This is the spores of the mildew.

If it looks like that, you probably might as well destroy all the affected plants to keep it from spreading. It is one of the really nasty ones. If there is no sporulation, then I would just pull off and trash (not compost) all the leaves with marks and then just keep an eye out and see what happens. Don't over water and don't water the leaves (only the soil).
Thanks so much I will look today for that. It is huge and smells great otherwise :)

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