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Rhopalosiphum rufiabdominale

Rice root aphid, Red rice root aphid

On this page: Identification & Distribution Other aphids on the same host Damage & Control

Identification & Distribution

Adult apterae of Rhopalosiphum rufiabdominale on the primary host (not pictured) are reddish-brown or greenish-brown with bluish-white mealy wax on the sides of the body and forming dorsal cross-bands. Apterae on the secondary host are dark green or brownish with a rusty-red suffusion about the bases of the siphunculi (see pictures below - note they are of immatures). The hairs on antennal segment III (see first clarified mount below) are markedly longer than the basal diameter of that segment; on the secondary host the longest hairs are 3-5 times the basal diameter (cf. Rhopalosiphum nymphaeae and Rhopalosiphum padi, which has the hairs on antennal segment III shorter than or equal to the basal diameter of that segment). Marginal tubercles are usually only present on abdominal tergites I and VII (cf. Rhopalosiphum nymphaeae, which has marginal tubercles on tergites I-VII). The siphunculi are less than 0.3 mm long, or 1.7-1.8 times longer than the cauda, and with no discernible subapical swelling (cf. Rhopalosiphum nymphaeae, which has siphunculi more than 0.3 mm long and swollen proximal to the subapical constriction). The body length of adult Rhopalosiphum rufiabdominale apterae is 2.0-2.6 mm.

Note:
Rhopalosiphum rufiabdominalis is a synonym for Rhopalosiphum rufiabdominale.

First image above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka (accessed 12/2/20).
Second image above copyright Whitney Cranshaw under a Creative Commons Attribution 3.0 License.

Alatae on the secondary host are dark green with a rusty suffusion around the bases of the siphunculi. They usually have 5-segmented antennae (see second clarified mount below) with 3-35 secondary rhinaria on antennal segment III, and 0-4 on segment IV.

Clarified mount images above copyright Brendan Wray, AphID, USDA APHIS PPQ, Bugwood.org
under a Creative Commons Attribution-Noncommercial 3.0 License.

Rhopalosiphum rufiabdominale is native to east Asia where it host alternates from Prunus species, including Japanese apricot (Prunus mume) and Chinese plum (Prunus salicina), to the roots of various grasses (Poaceae), sedges (Cyperaceae), potatoes / nightshades (Solanaceae), and cannabis (Cannabaceae). It has also been found overwintering in Europe on domestic plum (Prunus domestica) and apricot (Prunus armeniaca). Rhopalosiphum rufiabdominale is found in warmer climates, or glasshouses, in much of the rest of the world as anholocyclic populations on the secondary hosts. It is a major pest of rice in east Asia and of cannabis in hydroponic cultivation.

 

Other aphids on the same host

Primary hosts

Rhopalosiphum rufiabdominale has been recorded from 17 different species of Prunus (Prunus armeniaca, Prunus avium, Prunus cerasoides, Prunus domestica, Prunus glandulosa, Prunus ishidoyana, Prunus jamasakura, Prunus japonica, Prunus lannesiana, Prunus mume, Prunus nakaii, Prunus persica, Prunus pseudocerasus, Prunus sachalinensis, Prunus salicina, Prunus tomentosa, Prunus yedoensis).

Secondary hosts

Rhopalosiphum rufiabdominale has been recorded from more than 22 plant families - including many different grass & cereal species (Poaceae), especially rice (Oryza sativa), as well as from various Solanaceae and Cannabinaceae.

  • Rhopalosiphum rufiabdominale has been recorded on 1 Oryza species: Oryza sativa (Asian rice).

    Blackman & Eastop list 34 species of aphid as feeding on rice (Oryza sativa) worldwide, and provide formal identification keys (Show World list). Of those species, Baker (2015) lists 15 as occurring in Britain (Show British list).

  • Rhopalosiphum rufiabdominale has been recorded from 2 Triticum species (Triticum aestivum, Triticum durum).

    Blackman & Eastop list 60 species of aphid as feeding on 'common wheat' (Triticum aestivum) worldwide, and provide formal identification keys (Show World list). Of those species, Baker (2015) lists 30 as occurring in Britain (Show British list).

  • Rhopalosiphum rufiabdominale has been recorded from 3 Hordeum species (Hordeum rosa-sinensis, Hordeum sabdariffa, Hordeum vulgare).

    Blackman & Eastop list 47 species of aphid as feeding on barley (Hordeum vulgare) worldwide, and provide formal identification keys (Show World list). Of those species, Baker (2015) lists 26 as occurring in Britain (Show British list).

  • Rhopalosiphum rufiabdominale has been recorded from 3 Solanum species (Solanum italica, Solanum pumila, Solanum tuberosum).

    Blackman & Eastop list 22 species of aphid as feeding on potato (Solanum tuberosum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 20 as occurring in Britain (Show British list).

  • Rhopalosiphum rufiabdominale has been recorded from 4 Cannabis species (Cannabis sativa, Cannabis gigantea, Cannabis indica, Cannabis ruderalis - these are possibly all one species = Cannabis sativa).

    Blackman & Eastop list 6 species of aphid as feeding on hemp (=cannabis, Cannabis sativa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 5 as occurring in Britain (Show British list).

 

Damage and control

CABI Plantwise Knowledge Bank provide a useful summary of the information on damage by, and control of, this polyphagous pest. Rhopalosiphum rufiabdominale is an economically important pest of upland rice, particularly in Japan, but is not a pest of irrigated rice anywhere in the world. Injury to upland rice can be severe in Japan, with losses of up to 50-70%. Occurrence is related to the cultivars of upland rice in China, with aphids causing light damage at the seedling stage and heavy damage at the tillering stage. Generally, all aphids cause more serious damage during the early growth stages.

Rhopalosiphum rufiabdominale infests the roots of a range of other crops worldwide, including barley in Turkey, wheat in India, North America and Africa, aubergines in Spain, cotton in Africa and the USA, seed potatoes in India and sugarcane in Japan and India. It is probably frequently overlooked, especially in cereals. The record of overwintering on apricot Prunus armeniaca and common plum (Prunus domestica) in northern Italy (Rakauskas et al., 2015), indicates an increased threat of the aphid to cereal crops, and possibly stone fruits, in temperate Europe.

Rhopalosiphum rufiabdominale has become a pest of plants grown in hydroponic systems in greenhouses, in the USA and elsewhere, and under these circumstances can infest plants outside its usual host range. In 2004-2005 Rhopalosiphum rufiabdominale was first reported infesting greenhouse tomatoes and sweet peppers in Ontario, Canada - and greenhouse potatoes in Syria in 2007. In recent years it has become well known as a pest of cannabis (Cannabis sativa grown in hydroponic systems.

Rhopalosiphum rufiabdominale is also a vector of several plant viruses, including Barley yellow dwarf virus (BYDV) and Cereal yellow dwarf virus (CYDV), which contributes to its economic importance as a pest of barley in Turkey and North America. There is also evidence of it being a vector of Maize mosaic virus in India. Rhopalosiphum rufiabdominale has also been reported to transmit Sugarcane mosaic virus (SCMV) in India and is thought to be a non-persistent vector of Cucumber mosaic virus, which causes serious damage to tobacco in some areas in Taiwan.

Control of rice root aphid in rice fields is problematic. One of the few trials of insecticidal control was carried out by Barwal (2003) in India. Different formulations of insecticides were evaluated for efficacy and for effects on natural enemies. Four systemic insecticides, phosphamidon, monocrotophos, formation, thiometon and one contact insecticide, endosulfan, were found effective against the aphid without adversely affecting the parasitoids.

In greenhouses in Florida, the fungus Verticillium leucanii has been used to successfully control Rhopalosiphum rufiabdominale on squash (Cucurbita pepo), Etzel & Petitt (1992). An increase in the population of rice root aphids was observed following replacement of squash plants in a greenhouse in Florida during 1991. Aphids infected with Verticillium lecanii were introduced to the greenhouse in February. Fungal sporulation was observed 6 days after inoculation and a decrease in the population was observed after 2 weeks. Within a month of inoculation most of the aphids were dead. This procedure was subsequently routinely implemented for the control of Rhopalosiphum rufiabdominale. LaChapell in rice root aphid management and life cycle has proposed other mycopesticides including Botanigard (Beauveria bassiana) and PFR 97 (Isaria fumosorosea) for root aphid control, as well as Neem (azadirachtin) and Pyrethrin.

Acknowledgements

We are especially grateful to Sunil Joshi & J. Poorani, Aphids of Karnataka for permission to reproduce one of the images above.

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).

Useful weblinks

References

  • Barwal , R.N.et al. (2003). Seasonal activity and control of rice root aphid, Rhopalosiphum rufiabdominalis (Sos) (Aphididae: Hemiptera) in upland paddy. Indian Journal of Hill Farming 16 (1&2), 116-119. Full text

  • CABI. Species page: Rice root aphid. Plantwise Knowledge Bank. Full text

  • Etzel, R. W & Petitt, F. L. (1992). Association of Verticillium lecanii with population reduction of red rice root aphid (Rhopalosiphum rufiabdominalis) on aeroponically grown squash. Florida Entomologist 75(4), 605-606. Full text

  • Rakauskas, R. et al. (2015). Rhopalosiphum rufiabdominale: first records from winter host plants in Europe. Bulletin of Insectology 68(1), 73-81. Full text