''Metopolophium dirhodum'', the rose-grain aphid or rose-grass aphid, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
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/crop ...
found worldwide.
[ Its primary host is ]rose
A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can be ...
, and its secondary host is a grass, including cereals such as wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
, barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...
, oat
The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals). While oats are suitable for human con ...
s and rye. It is an important vector of the barley yellow dwarf
Barley yellow dwarf (BYD) is a plant disease caused by the ''barley yellow dwarf virus'' (BYDV), and is the most widely distributed viral disease of cereals. It affects the economically important crop species barley, oats, wheat, maize, trit ...
virus (BYDV) which causes serious reductions in yields of affected crops.
Distribution
The rose-grass aphid has an almost cosmopolitan distribution
In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extr ...
, 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
The cornicle (or siphuncule) is one of a pair of small upright backward-pointing tubes found on the dorsal side of the 5th or 6th abdominal segments of aphids. They are sometimes mistaken for cerci. They are no more than pores in some species.
...
(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 () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns ...
and cereal
A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food ...
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 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 shoots and ar ...
''), 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.[
]
Symptoms on cereals
Symptoms shown by the host plant include abnormally coloured and contorted foliage, deposits of honeydew with subsequent growth of sooty mould
Sooty mold (also spelled sooty mould) is a collective term for different Ascomycete fungi, which includes many genera, commonly ''Cladosporium'' and ''Alternaria''. It grows on plants and their fruit, but also environmental objects, like fences, ...
, yellowing of foliage and early senescence.[ This aphid is one of the most important vectors of the ]barley yellow dwarf
Barley yellow dwarf (BYD) is a plant disease caused by the ''barley yellow dwarf virus'' (BYDV), and is the most widely distributed viral disease of cereals. It affects the economically important crop species barley, oats, wheat, maize, trit ...
virus (BYDV).
References
{{taxonbar, from=Q10583201
Macrosiphini
Insects described in 1849
Insect pests of millets