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Hyperomyzus pallidus

Gooseberry-sowthistle aphid

Identification & Distribution  Biology & Ecology  Damage & Control 

Identification & Distribution:

Adult apterae of Hyperomyzus pallidus are opaque yellowish white or greenish. The legs and antennae are pale with dark apices to the segments. The siphunculi are dark-tipped and are 3-5 times longer than the maximum width of their swollen part. The swollen part is 1.6-2.4 times the minimum width of the basal part. The body length of adult Hyperomyzus pallidus apterae is 2.3-3.5 mm.

The secondary rhinaria on antennal segment III of the aptera are more or less evenly distributed along the length of the segment (compare Hyperomyzus lactucae  where they are clustered towards the base of the segment). The hairs on antennal segment III are short, only about a quarter of the basal diameter of that segment (compare Hyperomyzus lactucae where they are about a half of the basal diameter of that segment).

The clarified slide mounts below are of adult viviparous female Hyperomyzus pallidus: wingless, and winged.

Micrographs of clarified mounts  by permission of Roger Blackman, copyright AWP  all rights reserved.

The alate has a more-or-less solid black dorsal abdominal patch and blackish siphunculi. It has 50-75 secondary rhinaria on antennal segment three, 15-28 on segment IV and 0-9 on segment V.

The gooseberry-sowthistle aphid host alternates from the young leaves of gooseberry (Ribes uva-crispa) to the lower leaves of sowthistles (Sonchus spp.). Sexual forms occur in autumn. Hyperomyzus pallidus is found throughout Europe and in western Siberia, and has been introduced to North America.

 

Biology & Ecology:

There is very little in the literature about the biology and ecology of Hyperomyzus pallidus on either the primary or secondary hosts.

We have found them on gooseberry, the primary host, in May in mixed colonies with the currant aphid Nasonovia ribisnigri.

The picture above shows a single Hyperomyzus pallidus (centre screen) surrounded by a colony of developing fourth instar future alate Nasonovia ribisnigri.

On its secondary host, sow-thistle, it is often found in mixed colonies with Hyperomyzus lactucae.  Hyperomyzus pallidus prefers the undersides of lower leaves, often closer to the ground, whilst Hyperomyzus lactucae prefers the upper parts of stems and flowers.

 

Damage and control

Hyperomyzus pallidus is usually considered to be a relatively minor pest of gooseberry. Spring infestations on young shoots can cause stunting and leaf curl, as well as a characteristic yellow vein-banding of the leaves.

Acknowledgements

We especially thank Plumpton College  for their kind assistance, and permission to sample.

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994)  and Blackman & Eastop (2006)  supplemented with Blackman (1974) , Stroyan (1977) , Stroyan (1984) , Blackman & Eastop (1984) , Heie (1980-1995) , Dixon & Thieme (2007)  and Blackman (2010) . We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure  provided by Blackman & Eastop (2006).

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