Why are my tomatoes on the top wilting?

image from Sue 

Sorry I haven’t been posting.  I am still working on cleaning up the wagons and the plants.  But mainly I have been working on bookwork for Larry’s Garage.  I am gaining on it and will have statements to send out I hate to say from this spring.  We had such a good season at the greenhouse, I couldn’t keep up with the bookwork.  I have some call and see if I am still open which warms my heart, but I really don’t have plants for their gardens.   I guess I would say I am closed.  It was hard to keep all of them growing and well-watered when it was so hot during the Franklin Co Fair.  Time to let them go.  Thank you for a great season.  Total of 83 days working in a row at the greenhouse, and then the next week attended the Franklin Co Fair.  Few weeks later we attended the herb fest.  That put us into the first of Aug.  Not bad for someone my age and with 4 artificial joints. 
​
I have seen these tomatoes dry at the top, and was asked why they are wilting like this. I looked it up and this is what I found.  If yours did this, you will have to decide which reason why.  We have to be plant detectives when it comes to figure out why something isn’t growing correctly.   Good luck. 
Possible reasons for the tops of tomato plants wilting
Lack of water
Fungal wilt diseases
Tomato spotted wilt virus
Walnut toxicity
Stalk borers
Poor soil drainage
Root-knot nematodes (a common pest affecting tomato plants)
 Tomatoes Wilting Due to Fungal diseases
Fungal diseases  Verticillium wilt and Fusarium wilt are two different fungi that will cause your tomatoes to wilt once infected. The spores of these fungi can survive in the soil over winter or on plant debris that is left out in the field, and will enter your next seasons’ plants through their root system. Both diseases will cause wilting by growing up inside the xylem of the plant and blocking the transport of water and nutrients, thus causing leaves and stems to lose their turgor. Tomato plants and other vegetables in the nightshade family can be affected at any stage of growth, although it is thought that in Northern climates Verticillium wilt affects plants later in the season when soil temperatures are at least 70- 75℉. Fusarium wilt is more prevalent in Southern regions as it prefers temperatures of 80 – 90℉.
To confirm it is a fungal infection inside the plant, slice away a vertical section at the base of the stem and check for the presence of a brown substance inside.
With Fusarium wilt sometimes only one side of the plant will wilt and yellow, or just the lower branches.  Verticillium wilt starts affecting lower branches at first, and they may appear to recover at night only to wilt again during the daytime.
Solutions and prevention:
There is no cure for either of these fungal infections, and infected plants should be removed and thrown away immediately to prevent further spread- do not add to your compost pile!   Take many preventative measures to keep these fungi out of your garden, as Fusarium wilt can survive in the soil for up to 10 years!  Always remove plant debris at the end of the season, rotate crops in the nightshade family every season, solarize soil with tarps in the spring, buy resistant tomato varieties, and grow non-resistant varieties in pots to be sure these aggressive fungi have a very low chance of establishing themselves in your soil.
Viral infection Can Causes Wilting In Tomato Plants
Viral infection Tomato Spotted Wilt Virus (TSWV) will, as the name might suggest, cause your tomato plants to wilt and yellow.  It is transmitted by thrips, a common pest for tomato plants, which will pass the virus from their gut into the plant tissue of your tomatoes when they are feeding on them.
Identification:
Symptoms of TSWV include stunted or lopsided growth, brown flecks on the leaves, and raised circular areas and spotting on the fruits. Wilting usually occurs at the growing tips and new growth rather than on older, lower branches.  The only way to 100% confirm the presence of TSWV is to take a sample and send it into a local agricultural university lab.
Solutions and prevention:
Unfortunately, like the fungal infections, there is no cure for plants with TSWV. Infected plants should be removed ASAP and burnt or thrown out, and nearby weeds or plant debris should also be removed.   Purchase tomato varieties that are resistant to TSWV, and other preventative measures are focused on managing thrip populations in your garden, since they are the main vector for the virus.  Salicylic acid sprays can be used on tomatoes to ward off thrips, which won’t like to feed on plants with it on their surface. Sticky yellow and blue cards can be bought at plant centres or online and are particularly effective in greenhouses for catching thrips amongst other pests.
Pests Can Cause Your Tomato Plant To Wilt
Stalk borers and thrips  can cause your tomato plant to wilt after they enter or feed from it.  Stalk borers are small caterpillars- which turn into moths- that will bore a hole at the base of your tomato plant in the spring and tunnel into the main stem, impeding the flow of nutrients and water which causes wilting.
Identification:
There may be signs of a boring caterpillar such as excrement around the main bore hole somewhere near the bottom of the plant, or little holes that are used by the insect for breathing as it moves up the stem.  These will often be quite difficult to spot, so try to eliminate other possibilities and get to this cause through process of elimination.
Solutions and prevention:
If signs of the pest are noticed before extensive wilting has taken place, it is possible to remove this pest through a somewhat risky surgery. If you have located a bore hole and/or insect excrement, you can make a vertical incision on the stem and try to remove the caterpillar with tweezers. After removal, the plant must be patched up with horticultural tape and be carefully monitored, as this kind of opening can weaken the plant and create an entrance for other pests and disease.  If the plant is already severely wilted, the damage may already be done and the plant should be removed.
Taken from https://www.gardeningchores.com/tomato-plants-wilting/
Till next time this is Becky Litterer, Becky’s Greenhouse, Dougherty Iowa [email protected] 641-794-3337  cell 641-903-9365