Schizaphis graminum

The greenbug, or wheat aphid (Schizaphis graminum),[1][2] is an aphid in the superfamily Aphidoidea in the order Hemiptera.[3][4] It is a true bug and feeds on the leaves of Gramineae (grass) family members.[5]

Greenbug
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Insecta
Order:
Hemiptera
Family:
Aphididae
Genus:
Schizaphis
Species:
S. graminum
Binomial name
Schizaphis graminum
(Rondani, 1852)
Synonyms
  • Aphis graminum Rondani, 1852
  • Toxoptera graminum

Its original distribution is the Palaearctic, but it has been introduced to other parts of the world. It is one of about 40 recognized Schizaphis species worldwide.[6]

Description

Adult greenbugs are 1.3 to 2.1 mm (0.05 to 0.08 in) long. The head and thorax are straw-colored to pale green and the abdomen is mid-green, with a dark green dorsal stripe in late-stage nymphs and adults. The antennae are dark and the cornicles are pale with dark tips. Early in the season the adults are wingless, but under conditions of over-crowding, winged forms appear and migrate to neighbouring plants.[7]

Host plants

This aphid feeds almost exclusively on a range of grasses in the family Poaceae; genera attacked include Agropyron, Avena, Bromus, Dactylis, Eleusine, Festuca, Hordeum, Lolium, Oryza, Panicum, Poa, Sorghum, Triticum and Zea.[8]

Ecology
Adults infesting Sorghum bicolor

In warm or moderate climates, the greenbug reproduces by parthenogenesis, female insects producing nymphs at the rate of up to five per day on paspalum near the Florida coast. There are three instar stages and a generation length of seven to nine days at 60 to 80 °F (16 to 27 °C). In cooler climates, females mate in the autumn with winged males, and the eggs overwinter on such grasses as Poa pratensis.[9] Within the Post-Soviet states there can be up to fifteen generations in the year and the most favourable temperature is around 20 °C (68 °F) for wingless forms, and 27 °C (81 °F) for winged ones.[10]

When feeding on grasses, the aphids suck the sap and at first cause yellow or red spots on the leaves. As the greenbugs become more numerous, the plant progressively develop yellow and red hues, leaves die, roots die and in extreme cases, the whole plant succumbs. On susceptible cultivars of small grain crops, the plant size and yield are affected. In turf grass, the tips and blades of the leaves turn yellow with brown tips, which contrasts strongly with healthy leaves. As the leaves die back, the aphids move on to fresh foliage.[7]

The greenbug is the vector of several plant viruses including barley yellow dwarf virus, sugarcane mosaic virus, maize dwarf mosaic virus and millet red leaf virus.[8]

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References
  1. Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D. (red.) (24 September 2012). "Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist". Species 2000: Reading, UK.CS1 maint: multiple names: authors list (link)
  2. Remaudière, G. & M. Remaudière (1997), Catalogue of the World’s Aphididae, INRA, Paris 473 pp
  3. Miyazaki (1988). "Schizaphis (Homoptera, Aphididae) of Japan with descriptions of two new species". Japanese Journal of Entomology. 56 (1): 21–34.
  4. Robinson, A. G. (1972). "Annotated List of Aphids (Homoptera: Aphididae) Collected in Thailand, with Description of a New Genus and Species". The Canadian Entomologist. 104 (4): 603–8. doi:10.4039/Ent104603-4.
  5. van der Goot (1917). "Zur Kenntnis der Blattläuse Javas". Contributions à la faune des Indes Néerlandaises. 1 (3): 1–301.
  6. Bugguide.net. Genus Schizaphis
  7. van Emden, Helmut Fritz; Harrington, Richard (2007). Aphids as Crop Pests. CABI. p. 19. ISBN 978-1-84593-202-2.
  8. Nuessly, Gregg S.; Nagata, Russell T. "Greenbug, Schizaphis graminum (Rondani) (Insecta: Hemiptera: Aphididae)" (PDF). University of Florida: IFAS Extension. Retrieved 8 October 2016.
  9. "Schizaphis graminum Rond. – spring grain aphid, greenbug". Economic Plants and their Diseases, Pests and Weeds. AgroAtlas. Retrieved 10 October 2016.
  • Nuessly, G. S.; Nagata, R. T.; Burd, J. D.; Hentz, M. G.; Carroll, A. S.; Halbert, S. E. (2008). "Biology and biotype determination of greenbug, Schizaphis graminum (Hemiptera: Aphididae), on seashore paspalum turfgrass (Paspalum vaginatum)". Environmental Entomology. 37 (2): 586–91. doi:10.1603/0046-225x(2008)37[586:babdog]2.0.co;2. PMID 18419932.
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