I have recently started to look after a garden on the Greek island of Rhodes. the owner has told me that two of his hedge shrubs have died through not being sprayed with the insecticide Confidor. I somehow doubt it is due to insect infestation, as only 2 in the row have died, separated by a still healthy one. a nearby shrub has sticky white stuff on it as per photo and a very large pine tree stands within 3 metres of the shrubs. can anybody recognise and let me know any possible causes and what further action to take. I have already sprayed with the insecticide as per owners request.

That first photo does look like a very severe insect infestation.

How long have the shrubs been there? It looks like they are in a very dry situation.

Is there any way you can get a sharper picture than the top one? I'm wondering if that is scale insects but it's too blurry to see any details. Depending on the species of scale insect, if that's what it is, they may or may not be controlled by imidacloprid (the active ingredient in Confidor). Some scale insects secrete "honeydew" with could explain the sticky stuff.

I know that the top photo is insect infestation. I am more concerned about the hedge problem and it's possible cause. There is no evidence of insects within any of the hedge shrubs. They do receive water on a regular basis so it's not due to that.

So where is the first photo from?

First photo is from a shrub 3 feet in front of hedge. My main question is would insects deliberately omit one plant and not spread further outwards.
Excuse me if I come across as a bit dumb, but I am applying what to me is common sense .
Having said that, I am more than receptive to new knowledge.

The green shrubs either side of the dead-looking ones look to have some brown leaves adjacent to the dead ones, unless they are intermingled. Are you saying that the insects that are in the first picture are not on the dead shrubs at all? None of the pictures are clear enough or close enough to identify the problem or the insects, and without knowing what kind of shrubs they are we can't look up what they are prone to.

To answer your question about spreading, I have seen individual plants badly affected by scale insects next to ones that they haven't yet moved onto. But if there is no sign of the insects on the dead plants then that doesn't seem like the problem.