How can I get rid of the aphids on my cilantro?
Inspect the plants regularly to detect aphids early, before they get out of control. Remove and squish any you find. As well, move the affected plants away from others for several days. If you purchase new plants, keep them away from your other, established plants until you’re certain they are not infested.
The easiest method of controlling aphids is simply to dislodge them with a forceful stream of water from a hose. This can be repeated a couple of times a week. If the spray is not enough, wash each infested plant thoroughly in soapy water [about 2tsp (10 mL) of mild detergent per gallon (4.5 L) of water — by this, I mean the soap that you use to hand-wash dishes, NOT dishwasher detergent] – spray this onto the plant, making sure you coat all surfaces. Rinse with fresh water after around 10 minutes. You may need to repeat this after a few days.
Although many cosmetic pesticides are now banned in Ontario, insecticidal soaps are still available and can be used on herbs (which can be eaten later). Always read the label carefully, and use only products whose labels specify they are to control aphids. You might want to consider other strategies:
- plant other herbs, like sage, dill and thyme near the cilantro to discourage aphids
- attract beneficial insects like ladybugs, and wasps, which love to eat aphids –by growing flowers nearby that provide them with nectar and pollen. (One of the plants that attracts these insects is cilantro!)
- aphids like the colour yellow, so placing pans of water with yellow food colouring close to your infested plants may attract the aphids and drown them.
- use only fertilizers with moderate nitrogen concentration. Aphids love plants with high levels of nitrogen in their leaves.