1
point
How to prevent wilt on tomatoes?

Tomato    USA

My entire tomato crop was wiped out because my plants got wilt last summer, what’s the best way to stop the same thing happening again this year?


Posted by: Maggie Muffins (8 points) Maggie Muffins
Posted: March 2, 2013




Answers

3
points
That's a tough one as there are a number of possible causes of wilting, a soilborne fungal wilt like Fusarium or Verticillium, root knot nematodes, a walnut tree in the vicinity, herbicide drift. Most hybrid tomatoes varieties have resistance to nematodes and fungal wilts. Most heirloom varieties don't have much resistance to these pests. How many plants were involved? Did they die completely or were they just unproductive, even after watering?
If you are OK with growing hybrids, look for variety labels with letter codes such as VFN or VFNT. V stands for Verticillium wilt, F for Fusarium wilt, N for nematodes and T for tobacco mosaic virus. These designations are pretty commonly found. Less common would be a code like VFFNTASt. The double-F stands for Fusarium races 1 and 2; A for Alternaria stem canker, and St for Stemphylium gray leaf spot.


Posted by: Charlie B. (84 points) Charlie B.
Posted: March 2, 2013


deactivated commented,
That's a lot of very helpful information, thanks. I didn't know about the root knot nematodes. Seems like the nematodes are easy to identify based on the galls they produce. Are there any other means by which to tell the various causes apart, (e.g. fungal cause vs. viral cause)?
almost 6 years ago.

Maggie Muffins commented,
Thank you for your response Charlie, I had 8 plants in the garden and they did not die but did not produce either. I ended up pulling them out to try and stop it spreading to any other plants
almost 6 years ago.

Charlie B. commented,
Nematodes - root galls are diagnostic. TMV won't wilt the plants but would cause stunting and poor yield. Leaves could be distorted/bumpy/twisted with a mottled or mosaic pattern of light and dark green areas. Smokers need to wash their hands before handling plants because TMV is often present in tobacco. The fungal wilts could show up as whole-plant or one-sided. One useful diagnostic tip is to peel or shave off the epidermis and cortex from a wilted branch or stem and look for light brown streaks in the water-conducting tissue just under the surface. That's a good indicator of a fungal wilt.
almost 6 years ago.



2
points
Another issue that has been quite a problem in the last few years (especially in the northeastern US) is late blight. It does cause tomatoes to appear to "wilt" over a very short period of time (sometimes a few days for varieties with low resistance). It is caused by a fungus (Phytophthora infestans) and in my experience spreads best in nice moist weather. You can use copper sulfate fungicides as a protective measure, but they only really worked well for me if I applied them before the disease arrived in the area, and if I made sure they were re-applied after it rained. The best way to combat it is to plant varieties that are very resistant. I have found most cherry tomatoes to be a good choice, including the plum type "Juliet", the smaller grape type "orange sunshine", and the newer variety "tomatoberry". A few larger fruited varieties have been specifically developed with blight resistance in mind in the last couple of years, including "Mountain Magic", "Plum Regal", and "Defiant PhR".

Cornell Extension has put out a nice info-sheet on managing this pest:
http://www.longislandhort.cornell.edu...
Some more info and images of the problem can be found here:
http://www.longislandhort.cornell.edu...


Posted by: Kerry Mauck (58 points) Kerry Mauck
Posted: March 3, 2013




0
points
In my part of the world, there are various disease organisms that can cause wilt on tomatoes. Fusarium and Verticillium are common fungal disease organisms. Bacterial wilt can be a problem also. Tomato Spotted Wilt is a virus disease that can cause a wilt also. It is imperative to have an accurate diagnosis to determine what disease organism (or other cause) is responsible in order to design an effective management strategy. Also stated previously, growing resistant varieties is a good thing. Doing this is perhaps the most effective and least expensive management option. Most states have a plant disease diagnostic facility associated with a land grant university in that state. A good place to start to get that accurate diagnosis of your tomato plants is to contact your local county Agricultural Extension office. In many instances, these folks can even make a "house call" to see your plants and their symptoms. There is usually an office in every county. Hope this helps.

Steve


Posted by: Dr Stephen Vann (1 point) Dr Stephen Vann
Posted: March 4, 2013




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