Merry Xmas & Happy New Year.

We are based between Strath & Langhorne Creek in South Australia and have had
trouble with yellowing of older leaves on our trees, primarily with the
Corregiola and a few Nevadillo.
After talking with a few people it appears to be a relatively common thing in
the Fleurieu Peninsula at present.
Various causes have been floated, some being salt problems after a wet winter,
boron and/or manganese deficiency, too much or too little water.

After some investigation we have discovered copperhead cockchafer beetle larvae
in the soil in reasonable numbers which eat the feeder roots and we believe are
the major cause of the problem. There is no damage to the canopy from the adult
beetles.
Tissue testing done a month ago showed no deficiencies within the plants and
irrigation should have been sufficient to prevent any possible salt problems
after the winter rains.

Tissue test results from the affected leaves are yet to be available.

We are treating with an insecticide through the fertigation and also Agriphos to
improve root health. We may also apply a worm casting formulation with a high
microbial count to help restore the balance in the soil treated by insecticide.

I would be interested if any other growers have experienced problems of this or
similar nature, and the conclusions drawn from their investigations.

Helen Morgan
Talinga Grove, SA
Talinga Grove Olive Oil