I understand that ants protect/move/farm aphids and I wonder if there
are any effective controls that concentrate on excluding/killing ants?

For example, a few weeks ago, I had aphids on my apple tree attended by
ants. If I had excluded the ants (greaseband on the trunk?) would that
have prevented/reduced the problem?

Steve Harris - Cheltenham - Real address steve AT netservs DOT com
A useful bit of gardening software at http://www.netservs.com/garden/

In article ,
(Steve Harris) writes:
| I understand that ants protect/move/farm aphids and I wonder if there
| are any effective controls that concentrate on excluding/killing ants?

No.

| For example, a few weeks ago, I had aphids on my apple tree attended by
| ants. If I had excluded the ants (greaseband on the trunk?) would that
| have prevented/reduced the problem?

No.


The species of ants that farm aphids are tropical and do not occur
in the UK. In the UK, some species of ants 'protect' and 'move'
aphids, but there is no evidence that it makes a major difference,
or even a significant one. And it is EXTREMELY unlikely that
eliminating the ants will eliminate or even significantly reduce
an aphid infestation.

Essentially, ants follow aphids and are best regarded as simply an
indicator of aphids.


Regards,
Nick Maclaren.

"Nick Maclaren" wrote in message
...

In article ,
(Steve Harris) writes:
| I understand that ants protect/move/farm aphids and I wonder if there
| are any effective controls that concentrate on excluding/killing ants?

No.

| For example, a few weeks ago, I had aphids on my apple tree attended by
| ants. If I had excluded the ants (greaseband on the trunk?) would that
| have prevented/reduced the problem?

No.


The species of ants that farm aphids are tropical and do not occur
in the UK. In the UK, some species of ants 'protect' and 'move'
aphids, but there is no evidence that it makes a major difference,
or even a significant one. And it is EXTREMELY unlikely that
eliminating the ants will eliminate or even significantly reduce
an aphid infestation.

Essentially, ants follow aphids and are best regarded as simply an
indicator of aphids.


Regards,
Nick Maclaren.

I have watched ants attacking ladybirds near aphids, effectively protecting
them. They may not do it deliberately, but if the ants get some benefit from
the aphids (why else follow them around) then protecting them in this way
would help the ants. OTOH if the aphids gain nothing by being protected from
ladybirds and the like, then so much for aphid control by predators or
selective spraying.

There might not be any evidence that it makes a major difference, but is
that because people have done the experiments and observations and seen no
relationship, or because no one looked?

--
Tumbleweed

Remove my socks for email address

In article ,
Tumbleweed wrote:
I have watched ants attacking ladybirds near aphids, effectively protecting
them. They may not do it deliberately, but if the ants get some benefit from
the aphids (why else follow them around) then protecting them in this way
would help the ants. OTOH if the aphids gain nothing by being protected from
ladybirds and the like, then so much for aphid control by predators or
selective spraying.

Not at all. It is very common for animals to perform actions that have
no useful effect because they had an effect earlier in evolutionary
history.

I have watched ants walking over ladybird larvae, completely ignoring
them.

There might not be any evidence that it makes a major difference, but is
that because people have done the experiments and observations and seen no
relationship, or because no one looked?

Some people have done experiments and found no difference. Nobody
so far has reported an experiment that detects a difference in the
UK.


Regards,
Nick Maclaren.

"Nick Maclaren" wrote in message
...
In article ,
Tumbleweed wrote:
I have watched ants attacking ladybirds near aphids, effectively
protecting
them. They may not do it deliberately, but if the ants get some benefit
from
the aphids (why else follow them around) then protecting them in this way
would help the ants. OTOH if the aphids gain nothing by being protected
from
ladybirds and the like, then so much for aphid control by predators or
selective spraying.

Not at all. It is very common for animals to perform actions that have
no useful effect because they had an effect earlier in evolutionary
history.

Can you give an example? As people research things more, it often turns out
that behaviours or attributes that were thought to be incidental, arent.

I have watched ants walking over ladybird larvae, completely ignoring
them.

But were there any aphids about? :-) And organisms arent perfect, I have
watched ants running about and missing small bits of food. That doesnt
indicate they dont pick up food.

There might not be any evidence that it makes a major difference, but is
that because people have done the experiments and observations and seen
no
relationship, or because no one looked?

Some people have done experiments and found no difference. Nobody
so far has reported an experiment that detects a difference in the
UK.



So if I notice ants consistently attacking ladybids&larvae on my apple tree,
and the aphids therefore being left alone, should I draw the conclusion that
;
a)killing the ants wont help reduce the aphids, or that,
b)theories of organic gardening re controlling pests with predators (or more
specifically aphids by ladybirds) is bunk?

--
Tumbleweed

Remove my socks for email address

In article ,
"Tumbleweed" writes:
|
| Not at all. It is very common for animals to perform actions that have
| no useful effect because they had an effect earlier in evolutionary
| history.
|
| Can you give an example? As people research things more, it often turns out
| that behaviours or attributes that were thought to be incidental, arent.

Piranhas attacking something dropped in the water. The grasp reflex
of human newborns. If I recall, Gould has other examples.

| I have watched ants walking over ladybird larvae, completely ignoring
| them.
|
| But were there any aphids about? :-) And organisms arent perfect, I have
| watched ants running about and missing small bits of food. That doesnt
| indicate they dont pick up food.

Yes, of course. Don't be silly. The ants were 'milking' precisely
the aphids that the ladybird larvae were feeding on. And the
coexistence went on for a long time.

| So if I notice ants consistently attacking ladybids&larvae on my apple tree,
| and the aphids therefore being left alone, should I draw the conclusion that
| ;
| a)killing the ants wont help reduce the aphids, or that,

Nobody has so far shown ANY evidence that ants cause an increase
in the number or severity of aphid infestations, let alone that
killing the ants will reduce the latter. But there HAS been some
evidence that (a) is true in at least the majority of cases.

| b)theories of organic gardening re controlling pests with predators (or more
| specifically aphids by ladybirds) is bunk?

Well, I have not seen it work. Ladybirds reproduce fairly slowly
and don't eat huge numbers of aphids, so I am unconvinced that
they make much difference in controlling infestations. Things
aren't as simple as that, because you can also control pests by
restricting sources (e.g. I am spraying my philadelphus with soft
soap now to protect my broad beans later).


Regards,
Nick Maclaren.

On Wed, 19 May 2004 07:08:25 +0100, Tumbleweed wrote:

"Nick Maclaren" wrote in message
...
In article ,
Tumbleweed wrote:
I have watched ants attacking ladybirds near aphids, effectively
protecting
them. They may not do it deliberately, but if the ants get some benefit
from
the aphids (why else follow them around) then protecting them in this way
would help the ants. OTOH if the aphids gain nothing by being protected
from
ladybirds and the like, then so much for aphid control by predators or
selective spraying.

Not at all. It is very common for animals to perform actions that have
no useful effect because they had an effect earlier in evolutionary
history.

Can you give an example? As people research things more, it often turns out
that behaviours or attributes that were thought to be incidental, arent.

I have watched ants walking over ladybird larvae, completely ignoring
them.

But were there any aphids about? :-) And organisms arent perfect, I have
watched ants running about and missing small bits of food. That doesnt
indicate they dont pick up food.

There might not be any evidence that it makes a major difference, but is
that because people have done the experiments and observations and seen
no
relationship, or because no one looked?

Some people have done experiments and found no difference. Nobody
so far has reported an experiment that detects a difference in the
UK.


So if I notice ants consistently attacking ladybids&larvae on my apple tree,
and the aphids therefore being left alone, should I draw the conclusion that
;
a)killing the ants wont help reduce the aphids, or that,
b)theories of organic gardening re controlling pests with predators (or more
specifically aphids by ladybirds) is bunk?


There's a summary of a paper he
http://www.blackwell-synergy.com/lin...d=hvenKPRD9TVh
One would *think* that ants protecting aphids would damage the plant more
than without ants. In some cases, they could be beneficial, by driving off
other herbivores (weevils etc), which would cause more damage.

You might also see on some plants, (particularly roses in our garden) a
coating of fine earth particles around parts of the stem. Break one open
and you'll find the thing full of aphids and ants. Certainly an number of
european ant species overwinter aphids and carry them or their eggs out to
feeding grounds in the spring. That doesn't meant to say that those plants
suffer more or less.

--
Tim C.

On 19 May 2004 07:23:09 GMT, Nick Maclaren wrote:

Piranhas attacking something dropped in the water.
Debatable whether that behaviour is useless nowadays. A fair amount of
edible dead animals or fruit will fall into the rivers and lakes. The times
they get it wrong are more than compensated for by the times they get to
the food first.

The grasp reflex of human newborns.
That's a good one. Also the "diving reflex".

If I recall, Gould has other examples.
Not one to shy away from controversy, was Gould.


Don't rule out the ant/ladybird larvae battles as being started by the
larvae They are aggressive hunters and may well have started attacking the
ants first.

--
Tim C.

In article m,
Tim Challenger "timothy(dot)challenger(at)apk(dot)at" writes:
|
| There's a summary of a paper he
| http://www.blackwell-synergy.com/lin...d=hvenKPRD9TVh
| One would *think* that ants protecting aphids would damage the plant more
| than without ants. In some cases, they could be beneficial, by driving off
| other herbivores (weevils etc), which would cause more damage.

Ye gods, just imagine. A treatment to protect broad beans against
weevils could be to infect them with aphids ....

As Wilde said, the truth is rarely pure and never simple. That
could be the motto of ecologists!


Regards,
Nick Maclaren.

On 19 May 2004 07:23:09 GMT, Nick Maclaren wrote:

| b)theories of organic gardening re controlling pests with predators (or more
| specifically aphids by ladybirds) is bunk?

Well, I have not seen it work. Ladybirds reproduce fairly slowly
and don't eat huge numbers of aphids, so I am unconvinced that
they make much difference in controlling infestations. Things
aren't as simple as that, because you can also control pests by
restricting sources (e.g. I am spraying my philadelphus with soft
soap now to protect my broad beans later).

While increasing the number of ladybirds and lacewings surely can't hurt, I
bet you'll find that birds take more aphids than ladybirds. Especially when
feeding nestlings. Sparrows and blue-tits appear to take a large number.
Let's face it, they're bigger, need more food and can scoff a lot more in
one mouthful than an army of beetles or lacewing larvae.

I've seen values for lacewing larvae of 300 per larva and 5000 per ladybird
(adult) advertised (in its life, not per day). That might be a lot for a
tiddly little insect but it's peanuts compared to what a tit can polish
off.

--
Tim C.

On 19 May 2004 07:54:02 GMT, Nick Maclaren wrote:

In article m,
Tim Challenger "timothy(dot)challenger(at)apk(dot)at" writes:
|
| There's a summary of a paper he
| http://www.blackwell-synergy.com/lin...d=hvenKPRD9TVh
| One would *think* that ants protecting aphids would damage the plant more
| than without ants. In some cases, they could be beneficial, by driving off
| other herbivores (weevils etc), which would cause more damage.

Ye gods, just imagine. A treatment to protect broad beans against
weevils could be to infect them with aphids ....

As Wilde said, the truth is rarely pure and never simple. That
could be the motto of ecologists!

Our motto was:
"If there are two theories to explain something, they're probably both
right", often changed to:
"If there's only one theory to explain something, they're probably both
right".

--
Tim C.

Xref: kermit uk.rec.gardening:205707


In article m,
Tim Challenger "timothy(dot)challenger(at)apk(dot)at" writes:
|
| While increasing the number of ladybirds and lacewings surely can't hurt, I
| bet you'll find that birds take more aphids than ladybirds. Especially when
| feeding nestlings. Sparrows and blue-tits appear to take a large number.
| Let's face it, they're bigger, need more food and can scoff a lot more in
| one mouthful than an army of beetles or lacewing larvae.

Yes. And most aphids reproduce like the THINGS from a 1950s B movie.

| I've seen values for lacewing larvae of 300 per larva and 5000 per ladybird
| (adult) advertised (in its life, not per day). That might be a lot for a
| tiddly little insect but it's peanuts compared to what a tit can polish
| off.

Yes. The trouble is that 5,000 per annum corresponds to c. 30 per
diem, and so you would need one ladybird per infected plant just
to keep up. My suspicion is that they are effective primarily at
ensuring that there is not too much of a build-up on alternate
host plants (often wild ones).

Which is definitely not to be sniffed at. As I posted, after having
seen a discussion of the alternate host plants of black bean aphid,
I am trying the solution of targetting THEM and not the beans!


Regards,
Nick Maclaren.