How to Kill Aphids on Nastursiums

Aphids suck the sap out of the leaves, stems and flowers of infested plants. They are attracted to many plant types, including trees, vegetables and flowers. The most common aphid to affect nasturtiums is the green peach aphid. This small, soft-bodied insect has yellow-green coloring. The aphids cluster in feeding groups on the underside of the leaves and along the stems of the nasturtiums. Black and brown colored aphid varieties may also infest the nasturtiums.

Pruning shears

Horticultural oil

Insecticidal soap

Plant nasturtiums in well-drained soil in full sun and provide them with approximately 1 inch of water a week. Properly tended, healthy plants are less susceptible to aphid infestations.

Remove damaged, yellowed and sick nasturtiums from the bed. Weak plants attract aphids, and the aphids may spread from the sick plants to nearby healthy nasturtiums.

Inspect the nasturtiums at least twice a week for signs of aphids, especially when temperatures are below 80 degrees Fahrenheit. Wash any aphids from the nasturtiums with a sharp spray of water from the hose.

Weed the nasturtium bed and surrounding areas weekly to prevent any aphids from migrating from the weeds to the flower bed. Destroy the weeds or dispose of them.

Prune away any badly infested leaves or stems from otherwise healthy nasturtiums. Dip the pruned foliage in soapy water to kill the aphids before composting it, so the aphids don't migrate from the compost pile to other healthy plants.

Spray infested nasturtiums with a horticultural oil or insecticidal soap. Repeat the application every two to three days until the aphids are gone.