Cereal leaf beetle

Adult beetles are 5mm long, with a black head, red thorax and shining blue/green metallic abdomen.  The grubs are small and slug-like with a humped back, but have 3 sets of legs near the head.

Both the grubs and the adult beetles feed on the veins on the upper leaves of the cereal or grass plant, stripping out the chlorophyll and leaving a 'window' like transparent patch along the leaf.  They are a common pest amongst cereals in general, particularly oats.

Overwintering adults appear any time from April and from mid summer lay orange coloured eggs on the upper leaves of host plants.  Ten days later, the larvae emerge and begin feasting on the plant.  After 3 weeks the larvae move to the soil to pupate and return to feast on host plants before moving during autumn to a site to overwinter.