We’ve grown Broad Beans on the allotment every year – I plant some seeds directly on the allotment in late October / early November, and the rest are sown in pots at home in late February, ready to be planted out in the spring.
Generally speaking, the second batch of beans gets caught with Black Bean Aphid (blackfly), whereas my first crop are fine. This year however, was a bit of a disaster…
According to my vegetable books, Broad Beans can suffer from four main problems:
Black Bean Aphid which suck the sap from the plant. Ants then gather to feed on the sugary residue, and also eat the larva of ladybirds, so there’s less predators for the aphids.
Broad Bean Rust certainly lives up to its name – there’s no mistaking this on the plant! This is caused by fungus, and apparently isn’t as damaging as chocolate spot, but can cause the plant to be left with no leaves. Leaving more space between plants is said to reduce the chance of rust by increasing the airflow, as is avoiding damp and humid sites. These broad beans are on an exposed north / northeast facing sloping site so I’m surprised they were so badly affected. However, the spores can survive over winter, so this could easily be the result of a previous year’s damp weather.
Finally, we have Chocolate Spot, which is also caused by a fungus, but this is worse in cool damp conditions.
Chocolate Spot not only can overwinter in the soil if infected plant matter was left to rot, but can also lurk in seeds – another good reason to not save seed from any plants which might have been affected!
Overall we have four out of four, and indeed a couple of plants have all four problems themselves. By the time the plants are at this stage, there’s no real hope for them, so today we’ll be pulling up all the affected plants and binning them. We have picked some broad beans from the decent plants, but Mum described them as “small” and “stunted” so I need to look closely at every plant and check if it has a problem or not, before deciding if it’s allowed to stay!
After clearing those Broad Beans, I’ll feed the ground to ensure there’s plenty of nutrients, and sow the Florence Fennel seeds I bought earlier in the year.
Next year we’ll take a break from growing Broad Beans so I’ll be browsing through the seed catalogues to try and pick something more suitable to grow.