Rhopalosiphum insertum Walker Applegrass aphid

The apple/grass aphid overwinters as eggs on apple, pear and certain other Rosaceae. During the summer, the aphids occur on cereals and grasses, their secondary hosts. Heavy populations on primary hosts in early spring can be damaging but usually occur only if the previous summer was wet and, therefore, conducive to the growth of grasses. Summer populations on cereals and grasses are of little or no importance, although the aphids are capable of transmitting barley yellow dwarf virus (BYDV). Apterae on cereals are broad-bodied (f .4-2.0 mm long), yellowish-green and somewhat dusky, with short, purplish-brown siphunculi. Those developing on apple and pear in spring are larger (2.f-2.6mm long), shiny yellowish-green to bright green, with a darker dorsal stripe and mainly green siphunculi; the siphunculi are distinctly flanged (Fig.l91f).

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