Greenhouse tomatoes

Lyn2

Why has my tomato plant suddenly developed die back from the top of the plant? It’s well ventilated and was growing well......

Hampshire_Hog

Lyn, It could just be sun scorch water at the roots only don't spray the plant with water if in a green house water the ground to raise the humidity slightly.

Now the bad news Sorry !!
It could be one of several diseases that can cause tomatoes to wilt from the top down. The plant could be suffering from a major bacterial disease such as Verticillium wilt or Fusarium wilt or it may be afflicted with Pith Necrosis.

Fungi that inhabit the soil and infect the plant through the roots cause both Verticillium wilt and Fusarium wilt. Damage results from the pathogen invading the water-conduction tissues (xylem) of the plant. Although symptoms of these two diseases are similar, Fusarium wilt tends to occur around midsummer when air and soil temperatures are highest. Often one side of the plant or branch will turn yellow and if sliced open, the xylem tissue in the stem will appear reddish brown. Symptoms of Verticillium wilt are similar, except the wilting is not restricted to one side of the plant of branch and this wilt tends to occur in late spring.

Pith Necrosis symptoms include thick stemmed plants with large canopies. The upper part of the plant may begin to wilt, and black streaks may be present along the length of the stem, which then becomes spongy and collapses.

In all three of these cases, affected plants should be immediately removed from the garden.

Pete.8

If you have a photo of the plant Lyn we may be able to get a better idea of the problem from that.

Lyn2

Thank you for your very detailed response. 

BobFlannigon

Lyn, quite often you can cut off the infected parts and dispose of them and the plant will continue on happily.  A photo would be good for us to give the best advice.