Pure stands of fava bean do not do a good job of suppressing weeds unless they are sown very densely. Planting fava bean in mixtures with other legumes or grasses improves weed suppression. Many beneficial insects, including predatory wasps and lady beetles, are attracted to the nectar of flowering fava bean. Fava bean also has extrafloral nectaries on its stipules, the leaf-like structures at the base of the leaf petioles. Extrafloral nectar is available to short-tongued insects that do not have access to the nectar of the legume flowers.
Fava bean is susceptible to aphid damage, especially from the bean aphid.
Although aphids usually do not affect fava bean's utility as a cover crop, they can cause considerable damage to the seed. Broadbean weevils also can reduce seed yields. Use of fava bean as a break crop has been reported to reduce the incidence of take-all in wheat. They seem to be better suited as winter cover crops in western Oregon because they are less susceptible to winter-kill. If you want to print this publication, we recommend downloading the PDF version.