Pear-bedstraw aphid

Identification:

Adult apterae of Dysaphis pyri medium to rather large globe-shaped, brownish-red to dark brown aphids. They are thickly coated with wax meal. The antennae are pale yellow near the base, but darker towards the apex.

The first 5 abdominal tergites have a double row of small dark spots. Hemispherical marginal tubercles are usually present only on abdominal tergites 1-5. The siphunculi are black and perpendicular to the body. They are 3.4-4.1 times their diameter at midpoint, and longer than the cone-shaped cauda (cauda is visible in the first image above). The adult aptera has a body length of 2.1-3.2 mm. Immature Dysaphis pyri are a pale yellowish brown, with reddish suffusion around the bases of their siphunculi.

Spring migrant alates have the abdomen brownish-red with a black dorsal patch. They have 23-36 secondary rhinaria on antennal segment III, 2-10 on segment IV and 0-1 on segment V.

The primary host of Dysaphis pyri is common pear (Pyrus communis). Leaves and shoots are yellowed and distorted to form a pseudogall (see second picture above). After about three generations on pear, alatae are produced which migrate to the secondary hosts. These are bedstraws, especially hedge bedstraw (Galium mollugo) and cleavers (Galium aparine) and sometimes squincywort (Asperula cynanchica). Dysaphis pyri may form colonies on the roots and prostrate stems, where it is attended by ants. Dysaphis pyri is found throughout Europe, the Middle East, North Africa and Central and South Asia, and has been introduced into the USA.