The Russian wheat aphid (Diuraphis noxia (Mordvilko)) infests wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and other small grains and grasses. Russian wheat aphid infestations are unpredictable in time and space. In favorable conditions, Russian wheat aphid feeding can result in heavy damage to wheat and barley in a short period of time. A repetitive monitoring strategy that allow...

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...

Wheat, Triticum aestivum L., with Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) resistance based on the Dn4 gene has been important in managing Russian wheat aphid since 1994. Recently, five biotypes (RWA1-RWA5) of this aphid have been described based on their ability to differentially damage RWA resistance genes in wheat. RWA2, RWA4, and RWA5 are of great concern beca...

the russian wheat aphid (rwa), diuraphis noxia (mordvilko), is a significant insect pest of wheat worldwide. the objective of this study was to assess the genetic variation within and between f2-derived families for reaction to rwa using f3 and f4 families originating from individual f2 plants of a cross between the susceptible line (synthetic hexaploid-11) and the resistance cultivar (‘halt’)....

Elicitors are molecules which can induce the activation of plant defence responses. Elicitor activity of intercellular wash fluid from Russian wheat aphid, Diuraphis noxia (Mordvilko) infested resistant (cv Tugela DN), and susceptible (cv Tugela), wheat (Triticum aestivum L.), was investigated. Known Russian wheat aphid resistance related responses such as peroxidase and beta-1,3-glucanase acti...

twenty-two bread wheat cultivars along with susceptible (sholeh) and resistant (azadi) control cultivars were evaluated for resistance to russian wheat aphid of two growth stages including seedling and stem elongation in greenhouse. five adult aphids per plant were used for infestation. leaf chlorosis at seedling and stem elongation stages and leaf rolling at seedling stage were measured. other...

in recent years, the russian wheat aphid, has been included worldwidely in the list of the important pests of cereals, particularly wheat plants. in addition to direct serious damage, the aphid is the main vector of barley yellow dwarf, barley mosaic, and sugarcane mosaic viruses. the pest was reported from east azarbaidjan province (iran) a few years ago and it is now widespread in tabriz,...

Chlorophyll degradation enzyme (i.e., chlorophyllase, Mg-dechelatase, and chlorophyll oxidase) activities of aphid-infested and uninfested 'Tugela' and Tugela near-isogenic wheat lines (i.e., Tugela-Dn1, Tugela-Dn2, and Tugela-Dn5) were assayed. Chlorophyllase activity was higher in bird cherry-oat aphid, Rhopalosiphum padi (L.) (Homoptera: Aphididae),-infested wheat lines compared with Russian...

J. Econ. Entomol. 89(3): 76C-770 (1996) ABSTRACT Experiments were conducted to compare the expression of Russian wheat aphid, Diurnphis noxia (Mordvilko), resistance in 2 genotypes of tall fescue grass, Festucn arun&nacea Schreb., harboring different isolates of the endophytic fungus Acremonium coenophialum Morgan-Jones & cams. Aphids did not select endophyte-free over endophyte-infected tiller...

The Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), is a serious wheat, Triticum aestivum L., and barley, Hordeum vulgare L., pest throughout the small grain-producing areas in the western United States. The virulency and classiÞcation of recently described Russian wheat aphid biotypes 1Ð7 (RWA1Ð7) were clariÞed using 24 plant differentials. These seven biotypes had bee...