I'm down to five tomato plants in my garden, four in-ground (healthy) and one in a container (sick). A few weeks ago I pitched two container growing tomatoes, certain they both had either Tomato Spotted Wilt Virus or Early Blight. Now I'm not so sure that was a good idea. The one remaining container plant is not only producing tons of little yellow tomatoes (sweet-n-neat-yellow) but they are bursting with great flavor too. The plant looks sick, really sick - the leaves have turned brown to crispy, almost appearing moldy in parts. It looks terrible, yet it is full of tomatoes that look healthy despite the foliage! What gives, and what's causing this?
Just like every year that something goes wrong with one of my vegetable plants I send it off to the Jefferson County Plant Diagnostic Clinic located at the Jefferson County Fairgrounds. My friend Patti got back to me in less than 24 hours with the diagnosis (very small fees apply). Are you ready? Any guesses as you look at the photos?
The good news is there is no disease, which explains why the fruit still tastes so good. Even though you can eat ripe fruit from a plant with Early Blight or TSWV, they just may not look normal and I find that the fruit with either of these ailments is below par in taste. Drum roll...this formerly cute little two-foot patio tomato is suffering from spider mite damage! Yikes, they are destructive. I usually associate spider mite trouble more on ornamental plants, so it didn't cross my mind to think they were the problem on my tomatoes.
You can read more about them on the fact sheet from Colorado State University - Spider Mites But in a nut shell, they are teeny, tiny spiders (related to ticks and scorpions), too small to see with your eyes. The two-spotted spider mite is the one that attacks vegetables and many other garden plants. They bruise leaf cells with their their mouth parts and eat the sap causing all sorts of damage including leaf discoloration and speckling. Their numbers are highest in July and August, reproducing very quickly. Severe infestations can greatly stress the health of the plant or cause death.
Insecticides may offer some control, but I personally won't use them. In many cases using chemical sprays only helps spider mite numbers increase by harming the beneficial control insects (carbaryl, found in the product Sevin). Spider mites not only like dry, hot conditions, but low humidity too. Lower humidity makes it a bit harder for natural predators like lady beetles and predatory thrips to prey on spider mites, but they'll do the best they can. Keep plants watered during dry spells (that means overhead watering on vegetables, do it early in the day so the plant dries quickly). Hosing down the plant will help kill or knock off the spider mites and dislodge their webbing, all good.
|The Plant Looks Almost Fine Far Away|