leaf yellowing, brown spots starting at leaf tip

16 years ago

My tomatoes have been doing splendidly until now and I just noticed some mottled yellowing and brown, dry spots starting at the tips of leaves on about 3 of my plants. These are happening on mature leaves but about mid height on the plant, not at the bottom.

I have one plant that has a touch of curl to some of the leaves, but not showing the leaf symptoms.

I did some searching and found maybe Potato leafroll virus or Septoria leaf spot could be possible? Or might they have some other deficiency? They look great otherwise.

http://vegetablemdonline.ppath.cornell.edu/PhotoPages/Tomatoes/Tom_Viruses/Tom_VirusesFS6.htm

Could anyone give their opinion and any ideas what to do? I prefer organic approaches. Copper spray?

Photos at link.

Thanks a bunch!

Here is a link that might be useful: Tomato leaf problems

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Comments (3)

chervena_chuska
Original Author
16 years ago
I was out looking at my plants more closely and did find some yellowing leaves in a couple of places near the bottom of the plant. This is leading me to this this is probably early blight. If someone could give me a second opinion, that'd be great.

I've done alternating copper spray and neem for early blight before (each on 7 day schedule). Is this a good strategy?

Thanks!
torquill
16 years ago
That looks physiological to me, not pathogenic. There are a couple of possibilities, depending on what you do with your plants.

Some nutrient deficiencies can look like that; magnesium, potassium, maybe molybdenum. If you haven't fed them recently, or if you have been feeding them a straight NPK food and your soil isn't the best, consider supplementing with a complete fertilizer or tonic, one which has trace minerals. (I'm fond of Superthrive for hard-to-pinpoint problems like this.) Low pH can also mimic nutrient deficiency.

It could be fertilizer burn, though it's not perfectly typical. If you've been feeding them a lot, lay off for a bit and see whether it resolves.

The last possibility I can think of is spray burn. Sulfur and some oils can burn foliage at high temperatures (over 85F) and even simple soap at high concentration can burn; it's common for the tips of the leaves to get higher concentrations of the spray as it runs off. You didn't mention any earlier sprays, but if you have done any, watch your temperatures and try to get an even spray without a lot of runoff. Don't mix different sprays together, either.

I don't suspect a fungus because the yellowing pattern is so regular, and the dead patches are in the center of the yellow areas which speaks of it either being the center of the toxicity/deficiency, or being a victim of sunburn as the leaves get too pale to handle the sun.

I hope some of that helps. :)

--Alison
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rowen_realtor
16 years ago
Mine have been doing that ... bright yellow streaks and now starting to brown. This happened last year and I had anthracnose, so I didn't know if they were related. Found what looks like scale on one of the leaves (small black dot with fringies)this morning. My plants are otherwise beautiful and fruitful. Good luck.