Fighting Pests & Problems for Your Tomatoes
Nematodes live in the soil and destroy tomato and pepper plants from the roots. You can use chemicals on them, but an even more effective killer is the humble, easy-to-grow Marigold! Click here to find out about Marigold Golden Guardian, which destroys more nematodes than commercial pesticides (and looks great doing it!).
Cutworms are caterpillars that chew through the stems of tomato plants. They're easy to conquer; just put a Cutworm Shield around each plant at transplant time, or make your own from coffee cans, plastic drink bottles with both ends cut out, or bio-degradable cardboard paper towel and toilet paper rolls. Be sure to sink the shield at least an inch beneath the soil as well as several inches above it for full protection.
Slow Growth, Yellow Leaves
At the first sign of this, spray your plants with seaweed, and keep reapplying every two weeks or so for the remainder of the season. The problem is probably lack of nitrogen -- your plants do need some nitrogen, though not much. If the seaweed doesn't help, your plants are diseased and should probably be pulled up.
Holes or Spots on Leaves
Many pests eat tomato leaves, and some diseases discolor the leaves. But unless your leaves are getting absolutely eaten up, don't worry about it. You probably have hornworms, potato beetles, or other parasites, but they shouldn't affect your crop.
Lots of Flowers but No Fruit
This is called blossom drop. Sometimes plants will set flowers but not fruit, due to anything from high humidity to rain to unseasonable cold. They must be pollinated to set fruit, and you can help get the pollen up and moving by shaking the plant (literally rattling its cage!) to loosen it up a bit.
All Leaves, No Fruit
If you've had blossoms but don't get fruit, many factors could be at work. Abnormally low (below 55 degrees F) or high (above 86 degrees F) temperatures while the fruit was setting could affect this, as could excessive nitrogen, high winds, and even heavy rains.
Funny-Looking Fruit
If your tomatoes have a mark or dark scar at one end, that's Blossom-end Rot, and it was probably caused by a sudden change in temperature during fruit set, or by a calcium deficiency. Either way, just cut the affected part off and enjoy the rest of the Tomato! If your fruit is kind of marked all over, that's Cat-facing, and it was probably caused by transplanting too early, insufficient water, or unusually high temperatures. Again, the fruit is fine to eat; just cut away the scarred areas.
Birds often peck tomatoes to bits for the water inside, so savvy gardeners place a big birdbath near the tomato patch. Pie pans and other shiny objects that catch the light will frighten some birds away from the crop. And some gardeners believe in decoys -- anything from shiny red cans to balls to other bright objects -- that mimic the look of a tomato. Tie the decoy to the plants a week or so before the fruit begins to appear and -- so the story goes! -- the birds will try to peck it, discover that it's no good, and leave your tomatoes alone. (I'm not sure how much faith I have in that remedy, but it's free and worth a try!)
Find a complete list of pests and beneficial insects with pictures and treatment options in Park Seed's app From Seed to Spoon.
