Pest, disease or nutrient deficiency?

[Jiminy Cricket]

Hey there,

Need some help identifying the cause of yellowing of the outer of the bottom leaves of one of my tomato plants in red clay soil. Three other tomato plants are showing none of the signs. Is it a pest, disease or deficiency?

Thanks!

[MissS]

It depends. How old is this plant and where is this leaf located on it? If it is a mature plant and this leaf is at the bottom, it could just be an older leaf that is no longer needed and the plant is shedding it. If this is the case then just cut it off.

If this is a young plant, then my guess would be magnesium deficiency. This can be corrected by feeding or spraying the plant with 1 tablespoon of Epsom salts to 1 gallon of water.

If this leaf is at the top or middle of the plant, then it might be mites. Look with a magnifying glass at the underside of the leaves.

[KarenO]

This is known as interveinal chlorosis.
On older leaves magnesium deficiency.
http://www.yara.us/agriculture/crops...ency---tomato/
KarenO

[zipcode]

I assume these are rather young plants? To have magnesium deficiency so early is odd, it usually becomes a problem after fruit are formed unless there 's something seriously wrong with the soil.
I would check the pH of the soil, maybe it's low, you shouldn't have these problems at this stage.

[ginger2778]

Deficiency, but I also see a spot of early blight. The concentric rings and circular yellowing past it are diagnostic. Definitely also a nutrient def..