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.