During the long dry spell, and I assume in consequence, blackfly proliferated in the garden. They were even on the holly shoots. Their natural predators, for example bluetits and ladybirds, didn’t seem to be on the job. I suppose normally we have a lot of both bluetits and ladybirds and not many aphids, so I shouldn’t complain. Recently we have been seeing ladybirds, generally harlequins (the one shown is on lavender in Camberwell). These are a bit bigger than 2-spots and 7-spots and have more spots (although they are variable and sometimes appear, for example, with two large red spots on black). Harlequins are fairly recent arrivals in Britain and are spreading out from the south-east. Entomologists are alarmed because while harlequins devour aphids voraciously they also attack other ladybirds. On the other hand no-one is suggesting any particular action, and none seems feasible.
Also, if harlequins are so good against aphids, and turn out against the blackfly, perhaps we should welcome them. I might be able to start growing broad beans again. I really don’t like blackfly, which probably do less damage than, say, woodpigeons, for which I have a soft spot. But if we didn’t have blackfly, or other aphids, what would the baby bluetits eat? and who would grudge a baby bluetit a meal?
