It’s early in the vegetable gardening season but it’s a good idea to go over a few things about your tomatoes in particular.
First, let’s talk about verticillium wilt (verticillium albo-atrum). This is a soil-borne fungal disease that tends to live in soils for extended periods of time. It’s important to note that in New Mexico there are many weeds in the nightshade family that are host plants for the fungus. So proper weed management is important.
The tell-tale signs that your tomatoes are infected with verticillium wilt are a yellowing of the leaves, particularly on branches closest to the ground, which will eventually turn to brown and die off. Often times the remainder of the plant will continue to grow and produce, but growth will be stunted and the fruit will either drop prior to ripening or often get sun-scorched from the lack of shade the plant leaves normally provide.
Once your plant shows signs, there is little that can be done to help it through the rest of the season. However, you can rotate your crops for the next few seasons and plant your tomatoes elsewhere in the yard or in pots. This will hopefully reduce the amount of fungus enough to safely plant tomatoes in the original spot at some point in the future.
Next, we’ll talk about beet curly top virus. This is a virus spread by the Beet Leafhopper (Circulifer tenellus) as it makes it way around the area. Again, it’s important to note the wild mustards, a staple of New Mexico weeds, are very common host plants for the virus.
It takes mere minutes for the hopper to feed on an infected plant and pass the virus on to to your tomatoes. And our sparse landscapes with clustered areas of vigorous growth are prime targets for leafhoppers.
Once the plant is infected it will show signs of leaves curling inward and cupping upward as well as very stunted growth within a week or two. It’s not necessary, but you may want to remove the infected plants just for being unsightly.
Though there is nothing you can do to help a plant once it’s infected, you may want to use row cover or frost blanket to cover tomatoes around dusk and keep them covered thru the early morning, this is when the hopper is most active. By preventing it from landing on your tomatoes, you’ll be protecting your crop.
Good luck with your crops this year. And please, let us know if you have any questions…
By Jennifer Timms Hobson, originally published May 10, 2012