[missmoneypenny]

So I decided to be ecological this year. the beans were attacked by blackfly as usual. But they had quite a few ladybirds on them so i decided to squish, and spray with water. Well the returns were minimal. Actually all that force from the water spray has weakened the leaves. The ladybirds made merry on the plants and soon were laying eggs  and the plants were covered in their larvae. That's when I decided not to use pyrethrum But for every ladybird, there are 100 balckfly. The plants are stunted, the harvest totally wrecked, out of 10 plants i got a handful of pods.
Next year, it'll be pyrethrum all the way. I will remove any ladybirds and take them to another part of the allotment before spraying.

[Goneterseed]

I've been spraying mine with water with a couple of drops of washing up liquid in it, once a week for the last month. Hardly any blackfly on them now. I think they got the message.

[LottyLouis]

I came to within a few hours of digging my broad beans in - blackfly bust out. Everyday I squished and sprayed with soapy water with a few garlic cloves dropped into the bottle for good measure. Pinched out top shoots like a mad thing. I also put some potted French marigolds along the row. Now blackfly are are on the wane and virtually gone. Although a few plants do show signs of damage, the beans are looking good. Persistence and a bit of luck I think.
But here's my question. Do blackfly have a 'season'? Will they start to naturally diminish at some point?

[missmoneypenny]

I guess it must depend on a few variables such as size of colony, georgraphical location and others. I was hoping to reach that tipping point whereby they'd give up/ get depleted but it just didn't happen. I remember last year I did manage to control them without pyrethrum.

[Nobbie]

My broad beans have only recently germinated, so I hope they escape the black fly. Maybe the early beans get lots of black fly as the aphids breed faster than the ladybirds, so it takes a while for the ladybird population to catch up and establish a balance.

[Kleftiwallah]

I believe this is the reason for starting broad beans off into growth in the autumn so they get a head start and possibly a good crop before 'Black fly season'.  Cheers,  Tony.

[LottyLouis]

Interesting point, Nobbie. I read somewhere on this site recently that it's the early beans that escape the blackfly - they're in and out before the beasties get going! Just goes to show - again! - there's just no logic to it!   

[LottyLouis]

Exactamundo, Klefti.....I'm going for an overwinter broad bean this year - we'll see.   

[Snoop]

Somebody (Surbie, Newshoot, Sunshineband maybe?) recently remarked that their Wizard Beans had lots of blackfly but the harvest wasn't affected. They might be worth giving a go. Wizard are also apparently very hardy, so would be good for autumn sowing.

[surbie100]

Not me. Mine were aquadulce claudia. Even though they were sown the previous autumn they were covered with blackfly. BUT I did get a fairly good crop as most of the pods were formed before they arrived.

Am sowing Wizard next year.

[LottyLouis]

Ah ha - let's hear it for Wizard. I've just ordered mine for an overwinter thing. Whoo hooo!   

[Snoop]

Sorry Surbie. I wasn't sure who it was, but the comment stuck in my mind because I tried growing some, but they ended up rotting in the flooding. I'm determined to give them another go next year. They sound like winners.

[New shoot]

Somebody (Surbie, Newshoot, Sunshineband maybe?) recently remarked that their Wizard Beans had lots of blackfly but the harvest wasn't affected. They might be worth giving a go. Wizard are also apparently very hardy, so would be good for autumn sowing.

Me I think 

Mine were sown last autumn and have received absolutely no care except the odd handful of chicken manure pellets.  They look awful, but I have picked and picked them.  We have eaten loads and the freezer is stacked with beans, but because I saw ladybird larvae just as the blackfly got bad, they never did get sprayed, either with chemicals or soapy water.  I didn't squish either.

The plants are pretty much picked clean, but are still standing as they are now host to multiple ladybirds in various stages of development.  I'll grab a piccie next time I am on the plot so you can see how bad they are, but be warned, it is not pretty viewing 

[azubah]

My broad beans are badly affected by blackfly so I am going to try an experiment this year. I will cut down the broad beans when they are finished, but leave the roots in, in the hope they will survive the winter and send up shoots again. If it works I should have an early crop which might miss the blackfly.

[missmoneypenny]

My broad beans were planted in the spring, and late at that. it's true that the autumn ones I've done in previous years were not as badly affected. This year even the flowers were overwhelmed with blackfly, and just shrivelled up. Hence the pitifully small crop. I'll get my skates on this autumn and plant early ish.