Field surveys of soybean aphid, Aphis glycines Matsumura, and its natural enemies, as well as natural enemy exclosure experiments, were conducted during 2003 and 2004 in soybean fields near Langfang, China. In 2003, aphid density increased six-fold during 12 d in July from 66+/-12 per 10 plants to a seasonal peak of 401+/-79 per 10 plants. Aphid density remained high for another 10 d and declin...

Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this...

The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), has been a major economic pest of small grains in the western United States since its introduction in 1986. Recently, a new Russian wheat aphid biotype was discovered in southeastern Colorado that damaged previously resistant wheat, Triticum aestivum L. Biotype development jeopardizes the durability of plant resistance...

Facilitating the evolution of new gene functions, gene duplication is a major mechanism driving evolutionary innovation. Gene family expansions relevant to host/symbiont interactions are increasingly being discovered in eukaryotes that host endosymbiotic microbes. Such discoveries entice speculation that gene duplication facilitates the evolution of novel, endosymbiotic relationships. Here, usi...

It has been claimed that plant architecture can alter aphid reproductive rates, but the mechanism driving this effect has not been identified. We studied interactions between plant architecture, aphid density, environmental conditions, and nutrient availability on the reproduction of pea aphids [Acyrthosiphon pisum (Harris)] using four near-isogenic peas (Pisum sativum L.) that differ in morpho...

Schizaphis graminum (green bug; GB) and Sipha flava (yellow sugarcane aphid; YSA) are two cereal aphid species with broad host ranges capable of establishing on sorghum (Sorghum bicolor) and several switchgrass (Panicum virgatum) cultivars. Switchgrass and sorghum are staple renewable bioenergy crops that are vulnerable to damage by aphids, therefore, identifying novel targets to control aphids...

Medicago truncatula is attacked by a broad range of insect herbivores including sieve-element feeders, cell content feeders, and chewing insects. In M. truncatula, genetic resistance against insects has to date been identified only against aphids: single dominant resistance genes have been identified conferring resistance against the pea aphid, bluegreen aphid, and spotted alfalfa aphid. Aphids...

Sustainable use of insect resistance in crops require insect resistance management plans that may include a refuge to limit the spread of virulence to this resistance. However, without a loss of fitness associated with virulence, a refuge may not prevent virulence from becoming fixed within a population of parthenogenetically reproducing insects like aphids. Aphid-resistance in soybeans (i.e., ...

Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insectpathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly...

The soybean aphid, Aphis glycines Matsumura, is one of the most important economic pests affecting soybean production in Wisconsin and neighboring states. Since its discovery in 2000, the soybean aphid has become established in the North Central Region and presents a potential threat to the soybean industry. Insecticides are available for control of the soybean aphid, but are an additional prod...