Q. How do I control white flies in my dome?
A. The bad news is that you have white flies; the good news is that you have a number of options to try. If you catch the infestations early, you can take the time to treat individual plants with a dish soap, oil and water mixture (a recipe to try would be to mix 1 tablespoon dish soap with 1 cup of cooking oil and add 1 to 2.5 teaspoons of this solution to 1 cup of water). This mixture can be sprayed every 7-10 days and will affect all life stages of the fly. There are also non-toxic yellow glue traps widely available on the market that attract and capture the flying adults. We make our own traps by purchasing yellow plates and covering them with cooking oil. There are a wide variety of commercial non-toxic sprays to try as well if you’re feeling adventurous.
Ladybugs parasitize on the white flies and they also attack aphids, so it may be a good idea to release some in your dome. The white flies can also be physically removed from the plants by using a high pressure wash, vacuuming them off or removing the infected leaves. You may even need to go as far as removing the infected plants. We’ve also read that too much nitrogen or deficiencies in magnesium or phosphorus in the soil are believed to contribute to whitefly infestations, so it may be time to have your soil tested.