Does anybody know if this is friend or foe

The 2 possibilities for the cuckoo spit do t seem to harm the plants.

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I’ve just been out to the tunnel to check against some of what the RHS site said and right enough some of the leaf tips of the rosemary have gone black, I will need to investigate further. I also noticed earlier what seemed like a bee flying around now I’m not convinced as it was landing on leaves rather than the flowers of say the strawberries, me thinks it might be laying eggs on laves. I will try get a photo tomorrow