Geraniums may hold the key to controlling the Japanese beetle, which feeds on nearly 300 plants and costs the ornamental plant industry $450m damage each year, according to scientists with the Agricultural Research Service . Geranium petals paralyse the beetle for up to a day, by which time a predator has often gobbled it up. Meanwhile in the UK, the wildlife minister Huw Irranca-Davies has given the go-ahead for the release of the psyllid , an insect that will help stop the spread of Japanese knotweed, a devastating plant which costs the UK more than £150m a year to control and clearPhotograph: Stephen Ausmus/ARS