Tomatoes are the headliners of the vegetable garden. In fact, for many gardeners, they are an obsession! Despite our love affair with tomatoes, they do have their share of ailments. Here are a few of the more common tomato problems and some possible solutions.
Failure to set fruit is caused by a lack of pollination. Tomato flowers are primarily self-pollinated as the pollen is shaken loose inside the bloom by wind or the buzzing activity of bees, not their carrying pollen from flower to flower.
Night temperatures below 55 or above 70 degrees, and daytime temps above 85 also can reduce fruit set, as can excessive nitrogen levels early in the life of the plant. Temperatures are not in our control, so we need to plant in early spring so the plants can set fruit when temperatures are still moderate. Choose fast-maturing varieties, preferably less than 75 days to harvest. Note also that cherry and grape types set fruit better in the heat than larger slicer type tomatoes.
Blossom end rot (BER) is caused by a lack of calcium to the tip of the fruit brought on by low soil calcium levels, or soil moisture fluctuations from wet to dry. BER is worse on the first tomatoes of the season and with container-grown plants since they can dry out faster. Keep the soil evenly moist. There are sprays containing calcium that can prevent BER if applied starting when tomatoes are about marble sized.
Stink bugs and their cousins, leaf-footed bugs, suck juices from tomato fruit, causing hard, white to yellow spots on the surface. Veteran gardeners learn to recognize and squish their egg clusters. The young wingless nymphs hang out in “herds” and can be easily knocked into a pail of soapy water. Sprays are also available as a last resort.
Plants may wilt and then perk back up in the early evening when the sun’s demands outpace the plant’s ability to take up moisture. If plants do not recover in the evening, it can be a sign of nematodes or fungal wilts attacking the roots.
If a plant wilts and doesn’t recover, pull it up with its roots and bring it to the extension office, where we can diagnose the cause. The solution to both soil fungal wilts and nematodes is to select varieties with a VFN after their name.
Curling of older leaves is a natural response in some varieties when summer temperatures rise and with high fertility levels but is no cause for concern. When new growth twists and curls, it is often a sign of virus infection or herbicide injury. Viruses can be spread by insects. Herbicide injury can occur from drift from lawn weedkillers, use of herbicide-contaminated sprayers, mulching with herbicide-treated grass clippings or hay, or an application of manure from cattle that grazed on treated pastures. Neither virus nor herbicide damage is treatable. Infected plants should be removed and discarded.
Fungal leaf diseases cause spots, blighted areas and yellowing, mostly on older foliage. Avoid wetting the foliage when possible, mulch the soil surface, and remove affected lower leaves promptly. Sprays for fungal diseases can prevent spread if used at the onset of infections.
Tomato fruit splitting is usually due to fluctuating moisture conditions. The cells in a tomato fruit keep dividing even though the moisture supply is limited. When a good rain or irrigation follows, they swell up faster than the skin can expand. The best solution is to keep moisture levels moderate, especially as the fruit nears ripening.
Some varieties are prone to cracks that appear around or a little out from where the stem attaches. This is not something that you can control and generally doesn’t ruin the fruit.
Spider mites cause tiny white specks in the foliage, eventually giving leaves a bleached-out or bronzed look. Blasting the undersides of all the leaves with a strong spray of water every week or so to dislodge the mites and their eggs or spraying the lower leaf surfaces with insecticidal soap can prevent outbreaks if started when signs of mites first appear.
Last but not least are birds, including our state bird the mockingbird, can cause problems. I love their beautiful songs and the fact that they eat insects but detest their interest in my tomato fruits. Bird netting or a well-trained cat are about the only ways I know to prevent damage, short of resorting to ballistic measures (which is frowned upon by neighbors and the local law enforcement).