I’ve noticed a few of my tomato plants have got curled leaves, lost their bright green color and their veins turn purple and I’ve got several friends with the same problem who have contacted me about what this might be. I’m pretty sure its Curly Top Virus transmitted from the beet leafhopper which has been really prevalent this season. This is not to be confused with leaf roll where the tomato leaves roll. I think the combo of leaf roll and purple veins is the key. Read on.
Here is some info on Recognizing Tomato Problems from Colorado State University website. http://www.ext.colostate.edu/pubs/garden/02949.html
‘Curly top virus is transmitted by the beet leafhopper. This problem is common in western Colorado but seldom found in eastern Colorado. Infected plants turn yellow and stop growing. Upper leaflets roll and develop a purplish color, especially along the veins. Leaves and stems become stiff; fruit ripens prematurely. It is difficult to control because leafhoppers migrate from southern areas. Hot, dry springs with predominantly southwest winds usually indicate increased problems with this disease. No chemical controls are effective. Use row covers to protect tomato plants from the leafhopper.’ Of course this is for Colorado but applies here as well.
Unfortunately after tomatoes get the virus, you should pull the plants. I’m concerned that a leafhopper might bite an infected plant and then bite a healthy plant and infecting it. So far 4-5 of my plants have this. I’m pulling them tomorrow..