Sipha maydis

Passerini, 1860

Hedgehog Grain Aphid

Sipha maydis, commonly known as the hedgehog grain , is a globally distributed pest of cereal crops and wild grasses. Native 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 plant worldwide. It reproduces parthenogenetically, with optimal development at 20–25°C. S. maydis is a of barley yellow 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//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other cereal aphids by its dark brown to black coloration and covering of white spine-like hairs. Yellow sugarcane aphid (Sipha flava) is bright yellow with rows of dark spots. Greenbug (Schizaphis graminum) is light green with a dark green stripe down the back. Corn leaf aphid (Rhopalosiphum maidis) is dark bluish-green with black , cornicles, and legs. In the field, look for yellow patches around colonies on affected leaves and attendant ants attracted to honeydew.

Images

Appearance

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

Habitat

Cereal crop 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

Native to Europe, Middle East, Asia, and Africa. First detected in North America in California in 2007, with subsequent detections 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 plant worldwide including wild grasses such as Leymus condensatus and Agropyron cristatum.

Host Associations

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

Life Cycle

Parthenogenetic with both (wingless) and (winged) morphs. 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 developmental threshold 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 honeydew that attracts ants. 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 crops, including non- plants such as lettuce.

Ecological Role

Pest of cereal crops causing direct feeding damage and transmitting barley yellow 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 natural enemy or observed at field sites.

Human Relevance

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

Similar Taxa

Sipha flavaYellow sugarcane aphid; bright yellow with rows of dark spots and short cornicles, does not produce honeydew
Melanaphis sacchariSugarcane aphid; pale yellow, gray, or tan with black feet, , and cornicles; produces abundant honeydew
Schizaphis graminumGreenbug; light green with dark green stripe down back, injects toxin causing reddish leaf spots
Rhopalosiphum maidisCorn leaf aphid; dark bluish-green with black , cornicles, and legs; typically feeds in