Corn leaf aphid colony in the base of barley flag leaf. Corn leaf aphid colony in the furled leaf of a barley tiller. Colonies develop only in the furled leaves, in the tips of tillers Life cycle Cereal aphids feed only on grasses and cereals. Over the summer they survive in low numbers on perennial grasses and self-sown cereal plants that have germinated after summer rains. The severity of an aphid infestation depends on the season.
Temperature determines the multiplication rate of aphids.
Ideally, a mild, wet summer followed by an early break in the season and a mild autumn provide favourable conditions for aphids. Cold conditions slow the rate at which they develop. Under ideal conditions, aphids can multiply rapidly. All aphids in a cereal crop are females, able to give birth to young, without the need to mate. Starting with a single aphid in ideal conditions, it is possible that a total of 3360 aphids can be produced over six weeks.