fava bean mold - Ask Extension
in my garden I have found mold inside the pods of several fava bean plants; a few of the pods have small black dots on the outside; and several leaves...
Knowledgebase
fava bean mold #877551
Asked July 16, 2024, 8:32 PM EDT
in my garden I have found mold inside the pods of several fava bean plants; a few of the pods have small black dots on the outside; and several leaves have black patches; several leaves have fallen to the ground. Some but not all of the beans inside the pods also have black spots. Can these be eaten? What causes this blight? Should I cut down all the plants, leaves and pods and destroy them? Can they be placed in the Portland compost bin? Any help you can offer would be greatly appreciated.
Multnomah County Oregon
Expert Response
I will ask another expert to comment. A couple of photos will help, if you can share those.
Here are the photos I took this evening. Douglas On 7/18/24 10:12 AM, Ask Extension wrote: >
Douglas: Fava beans are subject to quite a few fungal and bacterial diseases. I was doing a variety trial of fava beans in a fall-planted, over-wintered crop about 25 years ago. We had a wet spring and quite a few of the varieties showed disease issues (on a field that had not grown beans before). Some of the diseases were clearly seed borne to start with.
The diseases most likely are white mold, Ascochyta blight, and Botrytis blight. The black dots indicate either botrytis or white mold. The leaf damage tends to look more like botrytis but the white stuff is more like white rot. That said, you could have all three.
You should not eat anything that doesn't look as it should externally or internal in the pod. Don't save any of the seed for planting next year. And don't plant susceptible vegetable (see white rot list) plants there for 3 to 4 years at a minimum.
Remove the plants from your garden and do not put it in the general compost pickup since white rot sclerotia can live for 10-20+years in the soil. Not to sure if commercial composting would get it hot enough to kill the sclerotia. So into the regular garbage it should go.
Here are some links to the three diseases:
https://pnwhandbooks.org/plantdisease/host-disease/chickpea-garbanzo-bean-cicer-arietinum-ascochyta-blight
https://pnwhandbooks.org/plantdisease/host-disease/bean-snap-phaseolus-vulgaris-gray-mold
https://pnwhandbooks.org/plantdisease/host-disease/bean-snap-phaseolus-vulgaris-white-mold-sclerotinia-rot
Feel free to call me if you have more questions.
Chip Bubl OSU Extension Agent/Columbia County (retired) <personal data hidden>.
The diseases most likely are white mold, Ascochyta blight, and Botrytis blight. The black dots indicate either botrytis or white mold. The leaf damage tends to look more like botrytis but the white stuff is more like white rot. That said, you could have all three.
You should not eat anything that doesn't look as it should externally or internal in the pod. Don't save any of the seed for planting next year. And don't plant susceptible vegetable (see white rot list) plants there for 3 to 4 years at a minimum.
Remove the plants from your garden and do not put it in the general compost pickup since white rot sclerotia can live for 10-20+years in the soil. Not to sure if commercial composting would get it hot enough to kill the sclerotia. So into the regular garbage it should go.
Here are some links to the three diseases:
https://pnwhandbooks.org/plantdisease/host-disease/chickpea-garbanzo-bean-cicer-arietinum-ascochyta-blight
https://pnwhandbooks.org/plantdisease/host-disease/bean-snap-phaseolus-vulgaris-gray-mold
https://pnwhandbooks.org/plantdisease/host-disease/bean-snap-phaseolus-vulgaris-white-mold-sclerotinia-rot
Feel free to call me if you have more questions.
Chip Bubl OSU Extension Agent/Columbia County (retired) <personal data hidden>.
Dear Mr. Bubl, Thank you very much for this detailed answer to my fava bean disease questions. I cut down all of the plants this morning, pulled out all the roots and picked up all the leaves, putting them in bags and into the trash bin. It looks like the list of vegetables and plants I should not grow in that area for 3-4 years includes several I would normally plant in a rotating method, so I'll avoid all of those for the full four years. I may just also avoid fava beans now and consider planting other beans from now on. I am very grateful for your expertise. Sincerely, Douglas Fix Reed College On 7/19/24 9:22 AM, Ask Extension wrote: >
