gardenlen writes:
we have ben trapping male flies
for a decade now and until recent times it was a very effective tool,
but now not so in 2 weekly period the season before last (when we got
hit the hardest ever) we trapped about 900 male flies giver or take,
yet our total crop ot tomato's, pawpaw's and star fruit were decimated
not a single piece of fruit could used. we run our male traps all year
as the males can be around at odd seasons.

Your current findings interest me, because I'm comparing it with my
experience using a couple of homemade fruit fly traps about 7 years ago.
My recollection is of catching overwhelmingly FEMALE+- flies. I recognised
them as female by the long sting-like organ, the ovipositor, at the tip
of their abdomen. Almost all the fruit flies trapped were of this
description, so I reckoned it was an effective trap for the females. From
memory, it used the usual kitchen concoction of honey or sugar, vegemite,
etc. I'll check with google, as I probably wrote a bit about it at the
time, I was so impressed at what a simple lure could achieve.

I recall hearing that the recommendation for the pheromone sprays was
to spray it all over the foliage, and the females would lay their eggs
whereever they were attracted to, and on the balance of probability
this would most times be leaf rather than fruit.

Unless the males need the fruit sugar as a nutrient, there is little
other cause they would have to unerringly home in on anything
specifically resembling a fruit. Males would be singlemindedly seeking
females. Only if the humble fruit fly were to be staunchly monogamous
(or the males a 'one-shot wonder' ) would it seem that the trapping of
males could be an effective practical measure in preventing significant
fruit damage by the pest, IMHO.

The best lure for a male might be a captive female. So maybe a trap
that has first caught a few females might in turn become an effective
lure for for males?
--
John Savage (my news address is not valid for email)