How to Control Black Aphids on My Fava Beans

Cook fava beans before eating them.

Fava beans are grown as a cover crop to improve the soil or as a food crop. Unlike other types of beans that thrive in warm, moist conditions, fava bean plants need cool temperatures to grow. Pick them when they are green and the seed is visible in the pod. Black aphids are a common problem on fava beans, but they rarely diminish yields, and they attract beneficial insects to the garden. These insects feed on the black aphids, as well as other garden pests.

Things You'll Need

• Summer or superior oil
• Garden hose

Instructions

1. Pinch the tops of the plants off. The succulent top leaves are most appealing to aphids, so removing them may deter aphids to some extent. Allow the lower stems to blossom and produce pods.

2. Wash the plants with a garden hose, making sure you spray the undersides of the leaves, as well as the tops. Water the fava plants frequently, as well. When plants aren't watered regularly, the sap in their stems becomes more concentrated and more tasty to aphids.

3. Spray the plants with summer oil or superior oil. These products are similar to dormant oil used for spraying trees, but can be applied to plants during active growth. They are more effective than insecticidal soaps, but won't harm beneficial insects. Read the label to make sure the spray you are using treats aphids, and follow all directions carefully.

Tips & Warnings

• Some people become very ill after eating raw fava beans, advises the University of Minnesota. Remove the white outer shell of the seed and cook fava beans before eating them.

References

• SF Gate: Aphids? Spray Fava Plants with Summer Oil
• University of Minnesota Extension: Growing Beans in Minnesota Home Gardens

Resources

• Seasonal Chef: Nine Ways to Use Fava Beans