''Metopolophium dirhodum'', the rose-grain aphid or rose-grass aphid, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of sap-sucking insect in the family

Aphididae The Aphididae are a very large insect family in the aphid superfamily ( Aphidoidea), of the order Hemiptera. These insects suck the sap from plant leaves. Several thousand species are placed in this family, many of which are considered plant/cr ...

found worldwide. Its primary host is

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

, and its secondary host is a grass, including cereals such as

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

, oats and

rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...

. It is an important vector of the barley yellow dwarf virus (BYDV) which causes serious reductions in yields of affected crops.

Distribution

The rose-grass aphid has an almost

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

, being found in most parts of the world where its secondary hosts are grown. It was first detected in New Zealand in 1982.

Description

Wingless adults are between long, slender, glossy yellowish-green with a darker dorsal stripe. The antennae, legs and siphunculi (erect, backward-pointing tubes on the abdomen) are relatively long and pale in colour. Winged individuals are between long and a uniform green colour.

Life cycle

The species overwinters on rose, its primary host, as an egg. On hatching in the spring, rose-grain aphids feed on rose at first, but do not persist on it beyond about June in the northern hemisphere, dispersing to

grasses Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in ...

and

cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

crops in midsummer. On its primary host, it is less harmful than is the rose aphid (''

Macrosiphum rosae ''Macrosiphum rosae'', the rose aphid, is a species of sap-sucking Aphidoidea, aphids in the subfamily Aphidinae. They have a world-wide distribution and infest rosebushes as the main host in spring and early summer, congregating on the tips of s ...

''), but in some years the plants may be littered with white nymphal cases and large numbers of winged females may develop in late spring and migrate in "clouds" to its secondary hosts. Cereals that are used by this aphid as their secondary hosts include wheat, barley, oats and rye. Research in New Zealand showed that barley and oats were more affected by this pest than was wheat, possibly because the lower leaves of wheat, on which the aphids tended to congregate, became senescent early in the year, giving conditions unsuitable for the further growth of the aphid.

Symptoms on cereals

Symptoms shown by the host plant include abnormally coloured and contorted foliage, deposits of honeydew with subsequent growth of sooty mould, yellowing of foliage and early senescence. This aphid is one of the most important vectors of the barley yellow dwarf virus (BYDV).

References

{{taxonbar, from=Q10583201 Macrosiphini Insects described in 1849 Insect pests of millets Cosmopolitan insects