Brussels Sprout Infestation
 

Dear All,

Some of my brussels have developed fairly large (several cms diameter) dense
grey patches on the upper surfaces of the leaves. At first sight it looks just
as if somebody had poured water on them and then emptied the contents of an ash
tray on top - they are raised and look somewhat fluffy. Around the patches the
leaves are starting to yellow and shrivel a little.

At first I thought, fungal infection. But the symptoms don't really seem to
match what my books tell me about powdery mildew or grey mould.

On closer inspection the patches look more like aphid colonies - little grains
that occasionally move. I've seen brown aphids and green aphids, but never
grey before, so I'm still not sure.

Can anyone identify this, and, even better, recommend treatment?

Many thanks,
Ben

--
Ben Edgington
Mail to the address above is discarded.
Mail to ben at that address might be read.
http://www.edginet.org/

I have got the same problem - noticed it in previous years but never as
badly as now. There is an earlier posting entitled "greyflies" which deals
with this. Have just got some"Bug Free" to spray over the sprouts - only
trouble is it is too windy at the moment to spray

Jeanne


"Ben Edgington" wrote in message
...
Dear All,

Some of my brussels have developed fairly large (several cms diameter)
dense
grey patches on the upper surfaces of the leaves. At first sight it looks
just
as if somebody had poured water on them and then emptied the contents of
an ash
tray on top - they are raised and look somewhat fluffy. Around the
patches the
leaves are starting to yellow and shrivel a little.

At first I thought, fungal infection. But the symptoms don't really seem
to
match what my books tell me about powdery mildew or grey mould.

On closer inspection the patches look more like aphid colonies - little
grains
that occasionally move. I've seen brown aphids and green aphids, but
never
grey before, so I'm still not sure.

Can anyone identify this, and, even better, recommend treatment?

Many thanks,
Ben

--
Ben Edgington
Mail to the address above is discarded.
Mail to ben at that address might be read.
http://www.edginet.org/

" Jeanne Stockdale" writes:
I have got the same problem - noticed it in previous years but never as
badly as now. There is an earlier posting entitled "greyflies" which deals
with this. Have just got some"Bug Free" to spray over the sprouts - only
trouble is it is too windy at the moment to spray

Thanks for that, Jeanne. I somehow missed that thread over the weekend. Have
now read it, and it looks like I will have to get some insecticide.

Ben

--
Ben Edgington
Mail to the address above is discarded.
Mail to ben at that address might be read.
http://www.edginet.org/

The message
from Ben Edgington contains these words:

" Jeanne Stockdale" writes:
I have got the same problem - noticed it in previous years but never as
badly as now. There is an earlier posting entitled "greyflies" which
deals
with this. Have just got some"Bug Free" to spray over the sprouts - only
trouble is it is too windy at the moment to spray

Thanks for that, Jeanne. I somehow missed that thread over the
weekend. Have
now read it, and it looks like I will have to get some insecticide.

Before you do, there are alternatives. Brassicas can withstand salty
water, so try spraying with that; maybe with a squiret of washing up
liquid. Or, if there's enough area of healthy unaffected leaf, just tear
out the aphidy patches and dispose of them. Or, hang some nutfeeders on
canes to encourage bluetits. I have done this to remove really huge
infestations of aphids on trees, the birds clear them in the space of a
day or so.

Janet.

In article , Janet Baraclough
writes

a squiret

A technical term or a typo?
--
Kay
"Do not insult the crocodile until you have crossed the river"

"Janet Baraclough" wrote in message
...
The message
from Ben Edgington contains these words:

" Jeanne Stockdale" writes:
I have got the same problem - noticed it in previous years but never as
badly as now. There is an earlier posting entitled "greyflies" which
deals
with this. Have just got some"Bug Free" to spray over the sprouts -
only
trouble is it is too windy at the moment to spray

Thanks for that, Jeanne. I somehow missed that thread over the
weekend. Have
now read it, and it looks like I will have to get some insecticide.

Before you do, there are alternatives. Brassicas can withstand salty
water, so try spraying with that; maybe with a squiret of washing up
liquid. Or, if there's enough area of healthy unaffected leaf, just tear
out the aphidy patches and dispose of them. Or, hang some nutfeeders on
canes to encourage bluetits. I have done this to remove really huge
infestations of aphids on trees, the birds clear them in the space of a
day or so.

Just 2p worth to add to Janet's posting. The aphids don't get it all their
own way. If you look very carefully at those colonies you may see shiny
brown/silvery objects that look like dried up aphids -that's exactly what
they are, they've been parasitised by a tiny wasp which lays its egg in the
aphid, the wasp larva feeds inside the aphid and kills it. Look even closer,
possibly with a hand lens and you'll see a single hole in the end of some of
them: an adult wasp has emerged from those to continue the good work. To see
the wasps look closely and don't think big, black and yellow - look for tiny
black insects only 2mm or so long with very slender bodies.

---
Rod

My real address is rodtheweedygardeneratmyweedyisp
Just remove the weedy bits
and transplant the appropriate symbol at.
..

In article , Rod Craddock
writes
Just 2p worth to add to Janet's posting. The aphids don't get it all their
own way. If you look very carefully at those colonies you may see shiny
brown/silvery objects that look like dried up aphids -that's exactly what
they are, they've been parasitised by a tiny wasp which lays its egg in the
aphid, the wasp larva feeds inside the aphid and kills it. Look even closer,
possibly with a hand lens and you'll see a single hole in the end of some of
them: an adult wasp has emerged from those to continue the good work. To see
the wasps look closely and don't think big, black and yellow - look for tiny
black insects only 2mm or so long with very slender bodies.

thanks - I'd wondered about them!

Currently I'm trying to spot my rsm predator among the red spiders ;-)
--
Kay
"Do not insult the crocodile until you have crossed the river"

Rod Craddock wrote:
"Janet Baraclough" wrote in message
...
The message
from Ben Edgington contains these words:

To see
the wasps look closely and don't think big, black and yellow - look for tiny
black insects only 2mm or so long with very slender bodies.

I found something big, black and yellow from the other end of the wasp
spectrum this morning. In the skimmer basket of my neighbours pool was
a beautiful Scolia flavifrons over 4cm long. My daughter said she had
fished her out of the pool twice last night, but she seemed bent on
suicide. When I found her in the basket she appeared to be dead so I
brought her home and put her in the small tray on my desk to show to a
young friend who loves "beasties" as much as I do. 14 hours later, I
have just noticed that she is flexing her wings, although not yet
making attempts to crawl. Hopefully by tomorrow she will be ready to
fly.
Good photo here
http://entomologia.rediris.es/aracne...1/14/fig03.jpg

--
Jo
Alicante

I have got the same problem with my cabbages also SWEDES!! after all they
are from the same family I will be out with the bug spray as soon as it
stops raining I think that the present mild damp weather could be causing
the problem any ideas
Thanks
"Ben Edgington" wrote in message
...
Dear All,

Some of my brussels have developed fairly large (several cms diameter)
dense
grey patches on the upper surfaces of the leaves. At first sight it looks
just
as if somebody had poured water on them and then emptied the contents of
an ash
tray on top - they are raised and look somewhat fluffy. Around the
patches the
leaves are starting to yellow and shrivel a little.

At first I thought, fungal infection. But the symptoms don't really seem
to
match what my books tell me about powdery mildew or grey mould.

On closer inspection the patches look more like aphid colonies - little
grains
that occasionally move. I've seen brown aphids and green aphids, but
never
grey before, so I'm still not sure.

Can anyone identify this, and, even better, recommend treatment?

Many thanks,
Ben

--
Ben Edgington
Mail to the address above is discarded.
Mail to ben at that address might be read.
http://www.edginet.org/

The message
from Kay contains these words:

In article , Janet Baraclough
writes

a squiret

A technical term or a typo?

It's a genetically mogified tree-rat. Fat stripey things that steal
bulbs and leave hair on the sofa.

Janet.