Chocolate Spot

Don’t get your hopes up. Chocolate spot is a fungal disease that attacks fava and other broad beans.

Chocolate spot is caused by the Botrytis fungi, a family of fungi responsible for gray mold on practically everything. Chocolate spot, in particular, is caused by Botrytis fabae.

Chocolate spot on fava beans (Rasbak) CC BY-SA 3.0

Chocolate spot symptoms

Moist conditions cause small reddish-brown spots to form on leaves and pods. These spots expand, leaving a dead, gray center. The fungi can spread so much that leaves and pods are aborted. And they certainly don’t look very appetizing!

How to control chocolate spot

As always, avoid overhead watering on plants susceptible to fungal disease. Black aphids are suspected carriers of the fungi that cause this disease, so controlling aphid populations may help. These fungi can overwinter in the soil and on decaying plant debris. Be sure to remove any infected plant material completely from the garden to avoid spreading the disease. Fungicides have been used to control chocolate spot, but timing is critical.