Abstract Plants have developed numerous strategies for responding to abiotic and biotic stresses. In particular, the microbiota surrounding plants may a positive effect on plant stress responses. One is reaction rhizobacteria, which can lead induced systemic resistance. Gram-negative soil bacteria that produce N -acyl homoserine lactones (AHL), example, Ensifer meliloti , induce primed state in...

Aphid parasitoids are common in Brazilian wheat fields, and parasitize aphids at the wheat tillering stage. However, there is little information available about when this natural enemy occurs in wheat crops. This study investigated the initial occurrence of aphid parasitoids in four commercial wheat crops in northern Paraná during the 2009 crop season. We installed two Malaise traps at each whe...

A protocol for isolating hemolymph from viruliferous aphids has been developed. This method uses warm melted wax to immobilize the aphid. Following removal of a hind leg, the hemolymph can be collected readily. Flushing with RNase-free water allows for collection of sufficient hemolymph for RNA extraction from individual aphids. The extracted RNA was successfully used for detection of barley ye...

Polygodial (1) and its derivatives acetal 2 (propylene) and 3 (ethylene) were prepared and their antifeedant activity and toxic effects evaluated on several insect species with different feeding ecologies (Spodoptera littoralis, Leptinotarsa decemlineata, Myzus persicae and Rhopalosiphum padi) along with that of polygonone (4). We also tested their selective cytotoxic effects on insect-derived ...

Pathogens and parasites can induce changes in host or vector behavior that enhance their transmission. In plant systems, such effects are largely restricted to vectors, because they are mobile and may exhibit preferences dependent upon plant host infection status. Here we report the first evidence that acquisition of a plant virus directly alters host selection behavior by its insect vector. We...

Rhopalosiphum padi L. causes significant damage to winter wheat (Triticum aestivum L.), even without obvious aboveground symptoms of injury. Our objectives were to develop a juvenile-plant bioassay for bird cherry-oat aphid (BCOA) resistance that allows rapid phenotypic differentiation. Central features of the bioassay include root and shoot weight measurements of 3-week-old seedlings produced ...

Holocyclic clones of the aphid Rhopalosiphum padi (L.) reproduce by cyclic parthenogenesis, whereas anholocyclic individuals are obligate parthenogens. Mitochondrial DNA and (mtDNA) and random amplified polymorphic DNA markers in R. padi as well as plasmid DNA markers of its bacterial endosymbiont, Buchnera aphidicola, were examined to determine the extent of genetic divergence between clones w...