So confused! (Yellowed or Spotted lower leaves = sick?)

[Arriga]

I don't know whether to pull up all of my mates or not. Several of my plants are yellowing from the bottom and some of the leaves have small spots on them. So far the mates look fine. No lesions on the stems. No hairy white stuff. I am almost scared to eat them. Please help!

[TZ -OH6]

It happens to all of us, every year to some extent. Two things happen to old leaves. The first is that the plant will pull nutrients out of them to support new growth causing the old leaves to yellow mid to late in the season, the second is that old leaves commonly develop fungal problems (spots and brown patches). Infection can be minor or major. If it is minor you can simply snip off the affected leaves and discard away from the garden, if major you may want to spray with a fungicide after removing bad leves. About the only time to pull a plant is when it is mostly dead or when it has a viral infection, in which case it will be really deformed.

[applestar]

Not to highjack this thread but:

TZ, is it OK to put the "yellowed/shriveled brown due to natural aging process" leaves in the compost? Of course today, I was too lazy to sort them as I pruned, so all lower leaves (apparently healthy yellowed/browned AND spotted -- from separate plants) got mixed together and went in the garbage.

Also, I tend to use non-seeding "weeds" as mulch as well as compost additions. I obviously wouldn't use tomato leaves as mulch for other solanacea like potatoes, eggplants, or peppers, but are there any other obvious no-no's? (I put healthy green tomato prunings around fern and astilbe planted in front of the Colorado blue spruce today....)

Arriga - I took the liberty of making the thread titie a bit more descriptive.

[SP8]

Sounds like a magnesium deficiency. Get hold of some Epsom salts.

[TZ -OH6]

Its best to keep all tomato and potato plant parts out of the garden compost because of disease. It is recommended to rotate these crops every year to prevent disease buildup in the soil,... and by putting diseased leaves in the compost you are defeating the purpose. Most gardeners do not have the space to rotate their crops so cleaning up diseased leaves is the best compromise. A hot compost pile will kill some of the disease spores, but you cannot gurantee that the all of the material gets to the center of the pile wher it is hot. We have all been hearing on the news about the prevalence of Late blight (which hits both tomatoes and potatoes) this year. You do not want that in your compost either.

Septoria spot and early blight are generally as common or more common than magnesium deficiency. Magnesium deficiency will not cause the spotting and larger dead patches the diseases will. Nitrogen deficiency is very common too now that the plants are growing strongly and the soil is drying up.

[applestar]

Thanks TZ. I ALWAYS throw out the obviously diseased leaves and plant remains, but you're saying don't compost apparently healthy ones right? I see what you're saying... but (sigh) that's an awful lot of plant material that can't be recycled and have to be put in the landfill. You're right though, that's probably the kind of undisciplined thinking that got us in trouble with the latest spread of disease in the first place....

I'm realizing we may not have entirely answered Arriga's question -- even if the lower leaves are affected by disease, the tomato fruits themselves are usually unaffected and I feel it's perfectly safe to eat them.

When the disease is blight, and it gets to the main stem, a brown/black streak can start climbing up the plant. Even then, I usually consider the tomatoes growing in the upper branches safe (but to be honest I haven't had blight problems with my tomatoes in a long time -- knock on wood! ). I always clip off (and discard!) any leaves that show signs of discoloration, because weakened vegetative matter attracts the "clean up crew" -- slugs, sawbugs, etc. that may stay to dine on the fruits. This also (hopefully) prevents the disease from reaching the main stem/artery and spreading through out (I call that "go systemic").

If fruit production has stopped and a plant is not recovering, I would probably harvest all healthy looking fruits, ripe, coloring, and green. Depending on how bad the condition, how far along in the season, and how many other healthy plant I have, I may or may not give the plant a week to see if it can recover without the stress of fruit production.

[TZ -OH6]

If a tomato looks good, I'll eat it. You can't taste the tomato diseases (if yuo can't see them), and they certainly won't hurt a person. I just wouldn't save seed from fruit growing near a diseased part of stem. Composting healthy tomato plant parts is probably OK, but you know how people are, if you don't say something is black or white they will make gray into any color they want. I have "wild" spots on my property so the tomato plants get piled up over in the weeds to rot at their leisure (or burned), but if I lived in a manicured neighborhood I would probably dig a shallow grave for them (cover with a bit of dirt) rather than send them to the land fill. They can be composted for landscape plants since their diseases only affect closely related species (Peppers, eggplant, potatoes, tomatoes).

[snowleopard394]

Even with late blight, even if you have a spot on the tomato itself, you can eat anything that hasn't rotted due to the spot. The fungus doesn't affect people.

[applestar]

Here's my take. I don't know what a late blight affected tomato spot looks like, but in the case of anthracnose, if a spot hasn't penetrated to the inside, then I just carve off the spot. If it has, then with tomatoes, I cut off the entire compartmentalized gel segment. Use good judgment though, fungus can grow long "roots" and may have penetrated deeper into the tomato flesh than you might be able to see. Once well established, it WILL affect the flavor -- in other words, if it doesn't taste good, DON'T EAT IT.

It's also not a good idea to expose yourself unnecessarily to fungal contaminants because some are toxic enough to affect people, some throw your gastrointestinal flora/fauna out of kilter, and others just add to your immune system's detox load. As my allergist said, it can be the "last straw on the camel's back" and you can become vulnerable to infections that you would not, ordinarily, be bothered with. Some medications intentionally weaken your immune system, so if you're taking any of those, you'll want to be more careful too.

[cottonpicker]

I'm fairly new here but believe I have something to add to the general knowledge. As far as "yellowing" of lower leaves is concerned... I just simply remove them for 'cosmetic' purposes and they are NOT threatening to the general health of your tomato plants. I believe the disease is most likely due to Septoria Spot or Septoria Spec and neither is harmful to the taste or health of the fruits. It is a MINOR problem and
definitely NOT harmful to your (human) health. It's NORMAL and comes from the normal movement of nutrients from older leaves to support younger leaves. Old supports New. That's life!!!! SO...... for cosmetic purposes, remove the yelowinfg & spotted, yellow leaves & look forward to more fruit!!!
LarryD

[Arriga]

I have so many green tomatoes and the thought of having to throw them away was getting to me. Again thanks.

[TZ -OH6]

Although Septoria and early blight are usually minor in that most plants may get a little bit on the lower leaves every year, under the right conditions (climate, tomato variety, strain of the fungus) they can quickly wipe out a plant, so when you see symptoms developing you should keep a close eye on how fast the infection is moving. If the weather hadn't of changed a few weeks ago I would have lost a couple of plants rather than just remove half of the leaves. Most of the plants around these (different varieties) only had one or two leaves affected. This type of thing is why I split my tomatoes into two very different growing areas and don't grow two plants of the same variety next to each other.