Hello Judith,

Scale is very hard to tackle, because the scale protects the insects from contact insecticides. Generally they're relatively well controlled by the natural predators , but in your case they're obviously not doing they're job. This is probably due to your spraying.

There is one very effective strategy in controlling these insects, one should wait until the beginning of spring when the younger scalelees insects of the new generation start to move. This is when they're vulnerable to contact insecticides like the ones you've used.
So you are left with two options:

* if your growing the olive organically, you will have to wait for the next spring, there is no point in doing anything now;

* if not, you can treat the plants with conventional insecticides, the best are: Methidathion, Phosmet or Carbaryl (these are the names of the active substances, you will search for the commercial names).

Cheers,

João

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João Correia
Cascais - Portugal
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