[sonnycbr]

What has killed my indoor and out door toms? I sowed a dozen Shirley seeds, growing them on into the healthiest plants I've ever had, so far so good. I started feeding after the first truss had set and they seemed to be flourishing. They set the fourth truss and started going yellow at the growing point. The disease spread down the plants rapidly, killing the lot in the space of a week! The only thing I've done differently this year is to have a couple of cucumbers in the greenhouse with the toms,(they,ve also gone the journey!) Could it be aphids, not that I saw many about. Any suggestions welcome for next year.

[paintedlady]

   that's bad luck sonny, sorry to hear that.  Growing cukes & toms in the same greenhouse is not ideal but they shouldn't be killing each other off either, so I'm sure that's not the problem.

Sadly, unless the whole plant is examined, "yellowing" on its own doesn't explain a lot as there are many things that make plants go yellow ... I'm sticking my neck out and saying overwatering might be a problem - when the roots get & stay waterlogged, the whole thing can then get terminal (do the roots look short, black and wizened?)  If not, are there grubs in the soil (same thing - damage to roots?)  I assume that you never found any other bug on the plants if you observed lack of aphid (have to say I've never had aphid problems on toms, but there's always a first.  Usually whitefly in greenhouses but there's no mistaking if you have an infestation of those!)

Other causes of yellowing don't necessarily kill the plant - such as being too cold, lack of sunlight, not enough nutrients and all of these can usually be remedied. 

Sorry I can't be of much more help - hopefully someone else can help