|I planted Nasturtiums in a long row. While they are flowering beautifully they have a tremendous problem with black bugs (aphids). There appear to be 40 eggs under almost each leaf. I have tried pyrethrin solution and pyrethrin solution with insecticidal soap. They appear to hurt the plants and not affect egg production. Also tried Lady Bugs (they all flew away) and a dilute sol'n of dishwashing soap.
|Generally, aphids can be controlled with insecticidal soap applied strictly according to the label instructions, but it is a contact insecticide and will not work on the eggs. Many gardeners find that a strong spray of water from the hose will knock them down sufficiently, but it will not kill the eggs either. Whatever method you use, the application needs to be repeated in order to catch any subsequent aphids generations after the initial adults are killed. Since it seems the plants did not tolerate the soap well, you might try the water approach. (As with any spray, it is usually a good idea to test it on a few leaves and see if there are any ill effects.) To be honest, if the soap didn't work you might want to take a sample to your County Extension (566-0673) for a definite identification of the pest and suggested controls, however if the plants are blooming well it may be that control isn't really all that necessary.|