Distribution of a New Invasive Species, Sipha maydis (Heteroptera: Aphididae), on Cereals and Wild Grasses in the Southern Plains and Rocky Mountain States.

Sipha maydis Passerini (Heteroptera: Aphididae) is a cereal pest with an extensive geographical range that includes countries in Europe, Asia, Africa, and South America. Reports of S. maydis in the United States have been infrequent since it was first detected in California, 2007.

Survival and Feeding Rates of Four Aphid Species (Hemiptera: Aphididae) on Various Sucrose Concentrations in Diets.

Different concentrations of sucrose were used to investigate how survival and feeding was affected in four species of aphids (Hemiptera: Aphididae). Seven sucrose concentrations were evaluated in feeding chambers fitted with parafilm membranes and infested with nymphs of Aphis glycines Matsumura, Diuraphis noxia Kurdjumov, Myzus persicae Sulzer, or Schizaphis graminum Rondani at 25 °C and a photoperiod of 14:10 (L:D) h. Survival on each diet was recorded 1, 3, 5, 7, 9, and 11 d.

More Virulent Offspring Result From Hybridization of Invasive Aphid Species, Diuraphis noxia (Hemiptera: Aphididae), With Diuraphis tritici Endemic to the United States.

The Russian wheat aphid, Diuraphis noxia (Kurdjumov), invaded the United States in 1986 and soon became a significant pest of wheat. Diuraphis tritici (Gillette) is native to the United States and was firmly established on wild grasses before the arrival of Russian wheat aphid. Both species are known to coinfest the same grass hosts, during the time they enter the sexual phase in the fall, mate, and produce overwintering eggs.

The Discovery of Resistant Sources of Spring Barley, Hordeum vulgare ssp. spontaneum, and Unique Greenbug Biotypes.

The genetic sources for host-plant resistance to the greenbug (Schizaphis graminum Rondani) in barley (Hordeum vulgare ssp. spontaneum) are limited in that only two single dominant genes Rsg1 and Rsg2 are available for the complex of greenbug biotypes. We evaluated four new barley lines from the Wild Barley Diversity Collection (WBDC) that previously showed potential for greenbug resistance.

Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States.

A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex.