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Qld Fruit Fly

PostPosted: Wed Feb 18, 2015 3:29 pm
by sci_fi
Hi Everyone,
Over the last weeks I have seen mountains of peaches decimated by the QFF near Beechworth Vic.
It is a tragedy.
I wonder whether the human species is that clever after all! We boast how "smart" we are most of the time but the Cane Toad and the QFF seem too smart for us.
anyway , my question is -

Why do these QFF larva drown in ambient tap water?

They don't seem to like water out of the hose into a bucket (that is lying in the sun) and they seem to die quickly.

If the QFF continues to get worse, I thinks our fruit will become a luxury.

Await your comments,

sci_fi

Re: Qld Fruit Fly

PostPosted: Wed Feb 18, 2015 4:26 pm
by Helix
They drown because they're air-breathers and can't breathe underwater.

(I might have misunderstood the gist of your question!)

Re: Qld Fruit Fly

PostPosted: Thu Feb 19, 2015 3:41 am
by roughbarked
Helix wrote:They drown because they're air-breathers and can't breathe underwater.

(I might have misunderstood the gist of your question!)

Yes. I think the question was possibly easily misinterpreted. The larvae are a lot more difficult to kill than that.

The adult flies would drown more easily but how to get them first into the water?

Re: Qld Fruit Fly

PostPosted: Thu Feb 19, 2015 5:15 am
by roughbarked
sci_fi wrote:Hi Everyone,
Over the last weeks I have seen mountains of peaches decimated by the QFF near Beechworth Vic.
It is a tragedy.
I wonder whether the human species is that clever after all! We boast how "smart" we are most of the time but the Cane Toad and the QFF seem too smart for us.
anyway , my question is -

Why do these QFF larva drown in ambient tap water?

They don't seem to like water out of the hose into a bucket (that is lying in the sun) and they seem to die quickly.

If the QFF continues to get worse, I thinks our fruit will become a luxury.

Await your comments,

sci_fi

I've had fruit fly larvae live for quite some time in shallow water in the sun in a wheelbarrow. I've stood there discussing the phenomena with fruit fly inspectors whilst attempting to squash live larvae between fingers.
Water out of the hose may well have been at searing temperatures if it had been laying in the sun. To leave such water in a bucket in the sun may have not decreased the water temperature by much. If there is anything that can kill fruit fly larvae naturally, it is by putting them in the heat of the sun where they cannot get away from it. Boiling water will kill them but they can survive at quite high temperatures. Put them on a dry hot surface and they will do all they can to find a way to get out of the sun. Though many will dehydrate in a short time it also depends upon their level of maturity. Many will immediately begin to seal up and wait until conditions are right to re-emerge as mature flies. Normally they'd do this after digging themselves into the soil but they don't actually need soil if they are mature enough to pupate and are dislodged from fruit.
The standard was to put all infested fruit in a plastic bag and leave it in the sun for several days. This does work but there are problems with it. Fruit fly larvae can get out of plastic bags. There should be a standard on the thickness of the plastic. I've triple bagged them and still observed larvae escaping.

Re: Qld Fruit Fly

PostPosted: Thu Feb 19, 2015 9:37 am
by Helix
Fruit fly larvae are maggots, not alien xenomorphs. What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

Re: Qld Fruit Fly

PostPosted: Thu Feb 19, 2015 9:50 am
by roughbarked
Helix wrote:Fruit fly larvae are maggots, not alien xenomorphs. What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

not arguing that.

Re: Qld Fruit Fly

PostPosted: Fri Feb 20, 2015 6:24 pm
by sci_fi
Thanks for the comprehensive and interesting reply Roughie.

There seems to be a paucity of info on what it takes to actually kill these suckers.

I agree, chucking them "in a plastic bag in the sun" is pretty vague.

I wonder if "we" could get a grant of say $20K and we could research the best and effective methods.

They are costing us big time at the moment. The extent of the damage is increasing.

sf

Re: Qld Fruit Fly

PostPosted: Fri Feb 20, 2015 6:35 pm
by sci_fi
>> What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

Granted. But once the offending fruit is cut open and the brown muck is scraped into a saucepan and covered in water, in afew hours they do seem to play dead. But are they?

We need some study here.
Maybe -
The effects of water temperature on mortality of Qld Fruit Fly larvae.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 1:06 am
by Helix
sci_fi wrote:>> What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

Granted. But once the offending fruit is cut open and the brown muck is scraped into a saucepan and covered in water, in afew hours they do seem to play dead. But are they?

We need some study here.
Maybe -
The effects of water temperature on mortality of Qld Fruit Fly larvae.



I'm not entirely convinced that's the most efficient way of dealing with the problem.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 9:42 am
by roughbarked
Helix wrote:
sci_fi wrote:>> What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

Granted. But once the offending fruit is cut open and the brown muck is scraped into a saucepan and covered in water, in afew hours they do seem to play dead. But are they?

We need some study here.
Maybe -
The effects of water temperature on mortality of Qld Fruit Fly larvae.



I'm not entirely convinced that's the most efficient way of dealing with the problem.


We used to have Fruit Fy exclusion zones. The fruit fly were in no way intimidated by road signs.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 10:27 am
by Helix
roughbarked wrote:
Helix wrote:
sci_fi wrote:>> What makes them difficult to kill is that they are normally protected by the flesh of a fruit.

Granted. But once the offending fruit is cut open and the brown muck is scraped into a saucepan and covered in water, in afew hours they do seem to play dead. But are they?

We need some study here.
Maybe -
The effects of water temperature on mortality of Qld Fruit Fly larvae.



I'm not entirely convinced that's the most efficient way of dealing with the problem.


We used to have Fruit Fy exclusion zones. The fruit fly were in no way intimidated by road signs.


Yes. Well. If the only ways you can think of dealing with them are a) cutting open the fruit, extracting the maggots and drowning them, and b) teaching fruit fly to read, then perhaps the problem's best left to the experts, eh?

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 12:04 pm
by roughbarked
Helix wrote:
roughbarked wrote:We used to have Fruit Fy exclusion zones. The fruit fly were in no way intimidated by road signs.


Yes. Well. If the only ways you can think of dealing with them are a) cutting open the fruit, extracting the maggots and drowning them, and b) teaching fruit fly to read, then perhaps the problem's best left to the experts, eh?


Hope that wasn't directed towards me.

The experts have been working on fruit fly for along time. I doubt they'd have bothered with the above method.
I've had all manner of experts in my backyard discussing it with me. Many methods have been trialled here.
We still have an ever increasing fruit fly problem. The cities dump so much and have little agricultural concern, thus are now the breeding grounds to spread from. The fruit fly exclusion zone at least when funded properly to prevent fruit fly from being transported was effective in the past. The whole thing though is difficult to police with the increase in traffic on the roads. Public education on the issue is sadly lacking.

The backyard fruit grower is now in dire straits.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 12:23 pm
by roughbarked
Bait sprays seem to be quite effective. Before the DPI lost funding to have a street tree bait spraying program, the fruit fly problem was not so bad. One of my neighbours (citrus orchardist) while on the edge of his farm bumped into the fruit fly inspector who said, "Col's place (next door) is riddled with fruit fly. How is it on your farm?" Ralph said, "I have none, if you'd care to come in and check, you will see." After the inspection, the fruit fly inspector took a bag of plums nectarines and peaches home to eat. During the discussion the bait spraying topic came up. The inspector was under the impression that both farmers were using the same methods. Not so. Ralph proved that Col wasn't spraying bait at all but merely relying on bait traps. Ralph bait sprayed every week without fail. He has also at his own expense travelled down from his farm to spray around the outside of my place and this part of the village. I haven't been here for almost five months yet I have no maggots in fruit.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 12:31 pm
by Helix
roughbarked wrote:
Helix wrote:
roughbarked wrote:We used to have Fruit Fy exclusion zones. The fruit fly were in no way intimidated by road signs.


Yes. Well. If the only ways you can think of dealing with them are a) cutting open the fruit, extracting the maggots and drowning them, and b) teaching fruit fly to read, then perhaps the problem's best left to the experts, eh?


Hope that wasn't directed towards me.

[snip]


You were the author of the quoted bit, so, yes, it was.

ETA: Backyard fruit growers can act as islands and reservoirs that assist in the maintenance and spread of pest populations.

Re: Qld Fruit Fly

PostPosted: Sun Feb 22, 2015 12:40 pm
by roughbarked
Helix wrote:
roughbarked wrote:We used to have Fruit Fy exclusion zones. The fruit fly were in no way intimidated by road signs.



You were the author of the quoted bit, so, yes, it was.

ETA: Backyard fruit growers can act as islands and reservoirs that assist in the maintenance and spread of pest populations.



Heh. :) No room for humour?

To ETA; Yes.

Re: Qld Fruit Fly

PostPosted: Mon Feb 23, 2015 5:40 pm
by sci_fi
I am still astonished that there is a dearth of info. on dealing with these QLD. FF larvae.

Your discussion and comments are interesting because the economic cost of the fruit damage is very large (and seems to be getting larger).
Entomologists must surely know a bit about a scientific basis for destroying the "maggots" Or do they?

I will make some inquiries and report back.

PS How many bananas did we loose with Cyclone Marcia?

sf

Re: Qld Fruit Fly

PostPosted: Mon Feb 23, 2015 10:11 pm
by roughbarked
sci_fi wrote:
I will make some inquiries and report back.



sf



OK..