Aphids often colonise the undersides of plant leaves where they are less visible to predators. In this photograph, you can see a number of lacewing larvae predating on an aphid colony gathered on the underside of a Lathyrus odoratus leaf.
Episyrphus balteatus, also known by its common name of marmalade hoverfly, laying eggs on a Sweet Pea tendril produced by one of the wigwam grown Sweet Pea plants, which were grown for my 2016 Sweet Pea Trial.
A hoverfly larvae on a Lathyrus odoratus leaf that is displaying evidence of the damage the aphid colonies have caused the plant. The white objects are the dead skins that the aphids have shed and discarded as they have grown, sometimes these dead skins are mistaken for whitefly, due to their similar appearance.