Sipha maydis

Passerini, 1860

Hedgehog Grain Aphid

Sipha maydis, commonly known as the hedgehog grain , is a globally distributed pest of cereal and wild grasses. to Europe, Asia, Africa, and the Middle East, it was first detected in the United States in 2007 and has since expanded across the Southwest and Rocky Mountain states. The aphid feeds on phloem of Poaceae, with documented including wheat, barley, sorghum, millet, and over 50 worldwide. It reproduces parthenogenetically, with optimal development at 20–25°C. S. maydis is a of barley dwarf virus and can cause leaf yellowing, rolling, and desiccation leading to yield reduction.

Sipha maydis by no rights reserved, uploaded by Jesse Rorabaugh. Used under a CC0 license.

Pronunciation

How to pronounce Sipha maydis: //ˈsiːfə ˈmeɪdɪs//

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Identification

Distinguished from other cereal by its dark to black coloration and covering of -like hairs. aphid (Sipha flava) is bright yellow with rows of dark spots. () is light green with a dark green stripe down the back. () is dark bluish-green with black , , and legs. In the field, look for yellow around aphid colonies on affected leaves and attendant attracted to .

Images

Appearance

Relatively small, pear-shaped , dark to nearly black in color. Body covered with distinctive , -like hairs visible under magnification—giving rise to the 'hedgehog grain aphid.'

Habitat

Cereal fields, particularly wheat, barley, and sorghum. Also found on wild grasses including johnsongrass, dallisgrass, and giant wild rice. Optimal temperatures 20–25°C; development hindered below 10°C and above 35°C. Survives winter temperatures down to approximately −16°C based on supercooling point measurements.

Distribution

to Europe, Middle East, Asia, and Africa. First detected in North America in California in 2007, with subsequent in Georgia (2012, glasshouse), Florida (2011–2012, on produce), and New Mexico (2015, established ). Expanded to Colorado, Utah, and Wyoming by 2015–2017. In South America, detected in Argentina in 2002 and spread rapidly.

Seasonality

Activity temperature-dependent; increase in warm, dry conditions. In temperate regions, active during growing season when temperatures exceed 10°C. In the U.S. Southern Plains and Rocky Mountain states, detected during spring and summer cereal growing seasons; winter survival limited by extreme cold events below −9°C.

Diet

Strictly phloemophagous; feeds on vascular sap of Poaceae. Documented include wheat (Triticum aestivum), barley (Hordeum vulgare), sorghum (Sorghum bicolor), millet, corn, and at least 52 worldwide including wild grasses such as Leymus condensatus and Agropyron cristatum.

Host Associations

Triticum aestivum - primary preferred
Hordeum vulgare - primary preferred
Sorghum bicolor - multiple including varieties
Millet - including Millex 32
Zea mays - corn
Leymus condensatus - wild giant wild rice; site of first U.S.
Agropyron cristatum - wild crested wheatgrass
Lolium multiflorum - Italian ryegrass; shows to endophyte defenses

Life Cycle

Parthenogenetic with both (wingless) and (winged) . Pre-reproductive period approximately 10.5 days at 25–30°C, 11–13 days at 23°C. Developmental time from birth to adult ranges 9.55 days at 30°C to 17.28 days at 15°C; no development at 32.5°C. Adult longevity 18–45 days depending on temperature and . Lower 4.2°C to −5.52°C depending on study; thermal constant approximately 244–332 . No sexual morphs observed in U.S. .

Behavior

Forms colonies on leaves, producing that attracts . Capable of rapid increase under favorable warm, dry conditions. Winged disperse to establish new colonies. In Argentina, spread across an area in 4 years that took 10 years to achieve. Can be transported long distances on commercial , including non- plants such as lettuce.

Ecological Role

Pest of cereal causing direct feeding damage and transmitting barley dwarf virus, one of the most destructive of small grain crops globally. Feeding causes leaf yellowing, rolling, and desiccation; heavy reduce yields and can delay maturity. In U.S. studies, no significant or observed at field sites.

Human Relevance

Economic pest of wheat, barley, and sorghum production. of barley dwarf virus. Management includes for yellow around colonies and attendant . (clothianidin, imidacloprid, thiamethoxam) and may be used. No significant damage observed in early U.S. surveys, but potential for increase if expand. sorghum effective against sorghum (Melanaphis sorghi) do not resist S. maydis.

Similar Taxa

Sipha flava ; bright yellow with rows of dark spots and short , does not produce
Melanaphis sacchari ; pale , gray, or tan with black feet, , and ; produces abundant
Schizaphis graminum; light green with dark green stripe down back, injects toxin causing reddish leaf spots
Rhopalosiphum maidis; dark bluish-green with black , , and legs; typically feeds in