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Indian grain aphidOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Sitobion miscanthi (see first picture below) are elongate ovate, and are variably coloured greenish-, yellowish- or reddish-brown to dark brown, with shiny black siphunculi and a pale cauda. The dorsal cuticle is variably tanned from pale, with only very small intersegmental sclerites, to having a large dark pigmented area which may be entire or segmentally divided. The antennal tubercles are large. The antennae are longer than the body, and have 3-5 circular secondary rhinaria on segment III in a row near the base. The longest hair on antennal segment III is 0.45-0.8 times the basal diameter of the segment. The rostrum reaches the middle pair of coxae. Abdominal tergites II-V usually have 2-6 marginal tubercles. The legs are pale brown, with the apices of the femora and tibiae darker. The siphunculi are cylindrical, long and slender, but expanded at the base. They are 1.4-1.9 times the caudal length (cf. Sitobion avenae, which has siphunculi 1.0-1.4 times the length of the cauda; and Sitobion fragariae, which has siphunculi 1.8-2.7 times the cauda). The siphunculi are slightly imbricated, and are reticulated over the distal 0.15-0.40 of length. The cauda is pale with about 8 long hairs. The body length of adult Sitobion miscanthi apterae is 1.7-3.0 mm.
Note: Sitobion miscanthi is closely related to the monoecious English grain aphid (Sitobion avenae) and the heteroecious Japanese grain aphid (Sitobion akebiae). The latter when on grass is morphologically indistinguishable from Sitobion miscanthi, and may be the same species (Yano et al., 1983).
Images above copyright Xin Jiang et al. (2019) under a Creative Commons Attribution-Non-Commercial licence.
Sitobion miscanthi alatae (see second picture above) are similarly coloured to the aptera, but with larger and darker dorsal abdominal markings. The body length of an adult alate is 1.9-3.1 mm.
The first image below shows a clarified mount of an adult apterous vivipara of Sitobion miscanthi. The second image shows a close up of the cauda and siphunculi - note the reticulated area on the apical third of the siphunculi.
Images above copyright Cameron Brumley, PaDIL under a Creative Commons Attribution-Non-Commercial licence.
Sitobion miscanthi is monoecious on grasses and cereals. It occurs on many genera and species of Poaceae and Cyperaceae, as well as some semi-aquatic dicots. Populations are nearly always anholocyclic, although oviparae and males have occasionally been recorded. The Indian grain aphid is found in the Indian subcontinent, east and south-east Asia and Australasia. It is a major pest of wheat in northern India and China, and can also cause significant losses in barley, oats, rye and sorghum.
Other aphids on the same host
Sitobion miscanthi has been recorded on 2 species of the Hordeum genus (Hordeum brevisubulatum, Hordeum vulgare).
Sitobion miscanthi has been recorded on 1 species of the Triticum genus (Triticum aestivum).
Sitobion miscanthi has been recorded on 1 species of the Zea genus (Zea mays).
Sitobion miscanthi has been recorded on 1 species of Oryza: Oryza sativa (Asian rice).
Damage and control
Sitobion miscanthi causes direct feeding damage as a result of extracting amino acids and carbohydrates from the leaves and heads. With heavy infestations yellowing is often evident on the leaves and ears. Honeydew deposits and the resulting sooty moulds reduce photosynthetic efficiency. Sitobion miscanthi is also a vector of barley yellow dwarf luteovirus (BYDV) and millet red leaf persistent luteovirus (MRLV). BYDV can cause serious losses when plants are infested early in the season. The crop most affected by the Indian grain aphid is wheat. Its pest status in India increased in the 1970s following the introduction of high-yielding Mexican varieties. It is also the most important pest of wheat in China.
The use of resistant varieties of cereals can reduce aphid infestations and yield loss. Most of the resistant varieties have been targeted towards other cereal aphids such as Schizaphis graminum and Sitobion avenae, but fortunately they tend to also be effective against other cereal aphids, as one might expect given how closely related Sitobion miscanthi is to Sitobion avenae. The most promising biological control agent is probably the parasitoid Aphidius uzbeckistanicus. Insecticide control is still used widely, for example in China where Sitobion miscanthi is the most widespread and harmful pest of wheat. Neonicotinoids such as imidacloprid and acetamiprid are used to control both Sitobion miscanthi and Rhopalosiphum padi. For more information on damage caused by, and control of, Sitobion miscanthi see Plantwise Knowledge Bank.