This magnificent caterpillar of the leafy Spurge Hawk-moth, Hyles euphorbiae, feeds on euphorbias and we’ve masses of those growing wild among the olive trees where we found this one.
The Americans wanted to eliminate these spurges because they produce an irritant white sap and are fairly resistant to most weed killers, so they introduced this moth into the USA. It was in fact the first classical biological agent approved for release in the States, in 1965, in Montana, Idaho, North Dakota, Minnesota, Oregon, and Washington.
And it was another example of government nonsense because research shows that although this caterpillar is a voracious eater, it has little or no impact on spurge populations. One reason is because Hawk-moth numbers generally remain low in an area due to predation (by mice which eat the pupae) and disease. So, Hyles euphorbiae plays only a very minor role in spurge biological control.