How Does Your Garden Grow?

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Over the past couple of weeks, the Cooperative Extension office has received several common questions regarding issues in the garden. The first issue involves rotting potatoes and declining vines. Unfortunately, if your potatoes were grown on a low row or planted too deeply, the wet conditions we have experienced can result in this early decline. If your potato vines are starting to turn yellow and wilt, consider harvesting a few potatoes now. Early harvested potatoes may not store as well, so go ahead and use them as soon as possible. Little can be done to rescue declining vines.

Another common condition that is showing up in the garden is the signs and symptoms of Tomato Spotted Wilt Virus (TSWV). This virus is spread by a tiny insect called Thrips and results in the wilting and decline of tomato plants. The characteristic sign for TSWV is the spotting that occurs on foliage and fruit that contains concentric rings. These rings look like the leaf has been tattooed and is unique to virus diseases. You may also see dark streaking in stems, bronze flecking on leaves, and the general wilting of plants. There is no rescue treatment for TSWV. Your best option is to replant if more tomatoes are desired, but choose a variety that is resistant to TSWV. The most common varieties that carry TSWV resistance are Amelia, Crista, Top Gun, and BHN 640. More varieties exist, so look at those plant tags before purchasing. I always recommend planting at least one TSWV resistant variety. Luckily, this virus is only transmitted by thrips, and will not persist in the soil.

picture of tomato plant leaf with TSWV

Tomato Plant with TSWV

Similar to TSWV, is the wilting disease known as Southern Bacterial Wilt.

picture of a tomato plant with Southern Bacterial Wilt

Tomato Plant with Southern Bacterial Wilt

Seed, plants, and soil are all sources of infection for this bacterium. Once your garden or pot is infected with this bacterium, you must either find a new garden location, replace your potting mix, or purchase resistant grafted tomato plants. Grafted tomatoes are grown on resistant rootstock with the desired fruiting variety grafted on top. Unfortunately, this bacterium persists in the soil for many years, so planting susceptible varieties back into the garden will result in reinfection. Signs and symptoms include wilting of plants, typically starting on one side, dark streaking and discoloration of the stem near the soil line, and rotting of the internal stem. If you suspect bacterial wilt, you can check for the presence of this disease by cutting a portion of stem from the plant near the soil line and suspending it in a clear glass of water. Milky white bacteria will stream from the cut stem and fall to the bottom of the glass. Be careful when disposing of plants infected with this bacterium. Remove these plants from the garden and do not place them near areas that may be used for growing other crops. Most crops are susceptible to this disease and vary in the level of response. Grass crops like corn are not affected.

One last garden issue that should be considered with great scrutiny is weed control. With warming temperatures and ample moisture, your gardens are probably experiencing a strong flush of weeds. Many gardeners are often frustrated with these dreaded weeds that can easily choke out that early promising crop. Cold steel and hot sweat can make quick work of weeds. Fast fingers make great weed pickers, but persistence is key. Some weeds will quickly reseed, germinate from underground root structures, or slowly creep in. Several herbicide options exist, but you must carefully follow label directions for optimum timing and restrictions. Weeds over 2-3” tall are not easily controlled by herbicides, and cultivation may be your only option. If you would like more information on weed control, consider reviewing the 2020 Southeast Vegetable Crop Handbook.

If you have additional questions about gardening or pest control in your garden, please contact Daniel Simpson at daniel_simpson@ncsu.edu or 252-745-4121.