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<pre>on 26/12/00 3:20 pm, Mohamed El-Kholy at adkholy@hotmail.com wrote:

> To Garth Renowden,
>
> Could the insects that you have seen in your flowers be olive leaf midge
> (dasyneura oleae)? I have never seen it in reality. The mature insect is a
> small fly 2.2 to 2.5 mm. Yellowish black in color. The mature female flies
> lay their eggs on the floral buds or leaves during springs. Eggs hatches in
> two weeks and the tiny larvae hides inside the leaves or flowers tissues to
> feed and this causes swelled spots on the leaves like knots. It can cause
> destruction to between 30 – 70 % of the flowers.
> Or was it the olive weevil.
>
> Kindest Regards to all,
> Mohamed

No, Mohamed, they're definitely thrips - the precise species I'm not sure of
- there are many - but see the following article by our local guru (don't
blush, Helen!). Another source is
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn030.html

From Olive Business, the newsletter of the Canterbury Branch of the NZOA,
Feb/March 2000 issue - by Helen Clausen, pioneer Canterbury olive grower and
presser of the first Canterbury olive oil, former chair of the NZOA R&D
committee:

"Thrips are tiny slender-bodied winged insects ‹ you need a magnifying glass
to see them in any detail. They are a global pest of many sorts of crops,
and love to eat growing tips and flowers, sometimes transmitting plant
viruses as they do so. They are widespread, and often sprayed off by
Canterbury grape growers during flowering.
Thrips have been noted to appear in some abundance on flowering olives. Four
years ago I remember having some discussions with a fellow grower about how
prevalent they were at flowering time. He suggested they may assist
pollination. It would now appear that the opposite is be true.
Close observation of the thrips this year showed that as soon as a single
flower opened the moist pollen inside the flower was being sucked out by the
little monsters, leaving a dry, pollenless flower that quickly turned brown
and fell off. This occurred even before the neighbouring flowers on the same
inflorescence were open.
To check that my suspicions were right I called in a consultant, who
confirmed what I thought. The thrips were devouring the pollen before it had
even dried out and was ready to be blown to neighbouring flowers. I was
advised to spray the little blighters. I have never used an insecticide and
was extremely reluctant to do so. I believe in the principles of organic
production and have been working towards an organic system, but my whole
crop of olives was threatened and I felt I was forced to spray. I should add
that the thrips were very thickly distributed mainly on the Barnea. They
were not so prevalent on the other varieties ‹ but they were present.
We used a pyrethroid spray, and fortunately only had to spray once. The
consultant had suggested that we might have to spray every seven days during
flowering, as more thrips could get blown into the grove. The results of the
spraying were instantaneous and quite miraculous. Without thrips, the
flowers opened and stayed white and on the trees for a good two weeks. I am
now very pleased to report that we have a good fruit set, the best we have
had yet."

Compliments of the season.
--
Gareth Renowden, Limestone Hills, New Zealand
Words, olives and truffles
Office +64 (0)3 355 9552 Home +64 (0)3 314 9921
Mobile 025 790 070
"I knew she carried a snorkel in her handbag, but would she use it?"(Sir
Henry)
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