Garden Organic explained one of its members had reported a nest of Nzara viridula – or southern green shield bugs – in London.
The pests, native to the south of Europe, have never been known to breed in the UK, but the changing climate may be making conditions more favourable.
According to the organisation, the bugs consume many species of plant, with tomatoes, alfalfa, curcubits and beans all on the menu.
However, it is sometimes difficult to notice they are there until a few weeks after the feeding, when fruit becomes distorted and leaves and blooms disappear.
Expert Sally Cunningham predicted more reports of nests will come in as the countrys climate gets warmer.
She said garden and greenhouse growers should be wary of “lentil-sized youngsters” on the underside of leaves.
“This is one clear indicator that climate change is impacting our gardens,” Ms Cunningham said, adding anyone noticing them should report it to the charity.
Meanwhile, Buckingham Palace was recently the recipient of a seed package from Garden Organic, as it looks to encourage the habit of growing your own fo