Avoiding black fly on broad beans?

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Avoiding black fly on broad beans?
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cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Sun Apr 30, 06 9:59 pm Post subject: Avoiding black fly on broad beans?
Does picking the tops off broad bean plants really work to prevent blackfly? When should I be doing this?

Blacksmith

Joined: 25 Jan 2005
Posts: 5025
Location: Berkshire

Posted: Sun Apr 30, 06 10:07 pm Post subject:
Never tried that ? A swarm of blackflies moved across our allotments last year (on the wind?), I sprayed mine with a very dilute mix of washing up liquid and water, seemed to do the trick.

gil
Downsizer Moderator

Joined: 08 Jun 2005
Posts: 18409

Posted: Mon May 01, 06 6:20 pm Post subject:

Blackfly infestation or otherwise depends on 2 things

Edited (after consulting Lampkin on organic farming) :
a) time of sowing : Autumn sowings are less prone to it because by June the following year, the tops are tough enough to not appeal to blackfly. Spring sown broad beans are particularly prone to attack, because when the blackfly arrive in JUNE, the beans have nice tender bushy tops. If you sow late in spring (like up here, when a mid-May sowing is possible), your beans may avoid blackfly, as their tops will not yet be sufficiently developed to attract the fly.

b) Place to land and infest : pinching out the bushy tops does seem to help. Do as soon as the tops are bushy, before June (if your broad beans have tops by then).

Blackfly danger dates : June.

Or pick / water them off. They don't like washing up water much, but they are tenacious little so-and-sos.

Lampkin recommends sowing barley on the headlands (areas at ends and sides of field) to protect commercial broad bean crops sown on a field-scale, as it has some effect in stopping blackfly coming in from outside the field. He does not say why this works [is it a barricade effect ? or do they land on the barley instead as a sacrifice crop ? or does the barley in some way repel them ?]

Last edited by gil on Thu May 04, 06 11:06 am; edited 1 time in total

Blue Sky

Joined: 30 Jan 2005
Posts: 7658
Location: France

Posted: Mon May 01, 06 6:43 pm Post subject:
And don't forget that the ants cultivate them for the sap they produce. Get rid of the ant and you are half way there (and vica versa). Tried wishy washy soapy water last year but to no avail. The bloody things killed the lot. Apparently the time to pinch the tops out is when four trusses of pods have developed. I'll be doing that this year.

Bernie66

Joined: 14 Jan 2005
Posts: 13967
Location: Eastoft

Posted: Mon May 01, 06 7:15 pm Post subject:
In my experience nothing works!

dpack

Joined: 02 Jul 2005
Posts: 45460
Location: yes

Posted: Mon May 01, 06 8:01 pm Post subject:
pinching encourages pod development . black fly are eaten by predators and dont like soapy drownings . spray with soap /drown with hose a few minutes later . i grow earlies ,mids ,laters and lates .3 out of four will be ok . the other can be treated , get aphids early and they are not that much of a problem .untreated they can wreck beans in a fortnight vigilence .and plenty of local nettles .

Blue Sky

Joined: 30 Jan 2005
Posts: 7658
Location: France

Posted: Mon May 01, 06 8:24 pm Post subject:

dpack wrote:

.... and plenty of local nettles .

All my nettles have gone into the nettle bin this evening in preparation for the nettle fertilizer next month. It worked a treat last year.

dpack

Joined: 02 Jul 2005
Posts: 45460
Location: yes

Posted: Mon May 01, 06 8:45 pm Post subject:
nettles are good preditor habitat though .

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Mon May 01, 06 9:16 pm Post subject:
The ant-aphid combination is always an issue here, its a dry soil and the ants love it. Can't use soapy water and hose down after, no hoses on our plots 'cos no taps. But a soapy water sprayer might not be such a bad plan I guess.

wishus

Joined: 24 Oct 2005
Posts: 777
Location: Northampton, East Midlands

Posted: Mon May 01, 06 10:47 pm Post subject:
Not noticed any black-fly, but my beans do have ants. I was going to ask if anyone had any anti-ant recommendations.

Blacksmith

Joined: 25 Jan 2005
Posts: 5025
Location: Berkshire

Posted: Tue May 02, 06 12:02 am Post subject:
poisonous blackflies ?

corinne

Joined: 06 Oct 2005
Posts: 69
Location: South London

Posted: Wed May 03, 06 5:35 pm Post subject:
A hose, dpack? We already have a hosepipe ban in our area. Watering the allotment is going to be a real pain if the weather is dry. My broad beans are being nibbled all round the edges by something. I have found a few little weevily-looking things - any clues? The damage is quite superficial at present.

dpack

Joined: 02 Jul 2005
Posts: 45460
Location: yes

Posted: Wed May 03, 06 5:50 pm Post subject:
opuntia species are nice as greens and the fruits are ace , the spines can be dealt with is it really that dry down south ?

Jb

Joined: 08 Jun 2005
Posts: 7761
Location: 91ï¿½ N

Posted: Wed May 03, 06 9:10 pm Post subject:

dpack wrote:

is it really that dry down south ?

It's not really that dry, perhaps 12% or so below average annual rainfall. It's more a measure of how critically close to capacity the south east is.

hedgehogpie

Joined: 02 May 2006
Posts: 684
Location: Kent

Posted: Wed May 03, 06 9:56 pm Post subject:

JB wrote:

dpack wrote:

is it really that dry down south ?

It's not really that dry, perhaps 12% or so below average annual rainfall. It's more a measure of how critically close to capacity the south east is.

Grrrr....... Yes! Don't let's go there - the amount of development going on around here will soon put paid to any illusions of Kent being 'The Garden of England'. Car park more like!

I am sooooo sick of being demonized by our local water board, they keep sending out little leaflets telling us how we ought to be using our water - if I get just one more telling me to put a brick in my cistern

I'll be giving THEM a demonstration of where to stick one!

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