Tissue location of resistance in apple to the rosy apple aphid established by electrical penetration graphs

A study of the constitutive resistance of the apple cultivar Florina, Malus domestica Borkh. (Rosaceae), to the rosy apple aphid, Dysaphis plantaginea (Passerini) (Homoptera Aphididae), was performed for the first time by the electrical penetration graph (DC-EPG) system, using the susceptible apple cultivar Smoothe as control. All experiments were conducted with apterous adult virginoparae. The results showed a constitutive resistance in Florina due to a much longer period before the first probe reflecting surface factors. Some weak indications were found for pre-phloem resistance and initiating phloem access was not affected as inferred from equal time to show phloem salivation. However, the complete absence of phloem ingestion indicates a major resistance factor in the phloem sieve elements, most likely in the sieve element sap. Surface factors could have affected tissue related variables and this should be studied further. Anyhow, the strong constitutive resistance in Florina, either on the surface alone or in the phloem as well, effectively prevented reliable experiments on induced resistance, previously detected by molecular methods

A lineage-specific Exo70 is required for receptor kinase-mediated immunity in barley

In the evolution of land plants, the plant immune system has experienced expansion in immune receptor and signaling pathways. Lineage-specific expansions have been observed in diverse gene families that are potentially involved in immunity but lack causal association. Here, we show that Rps8-mediated resistance in barley to the pathogen Puccinia striiformis f. sp. tritici (wheat stripe rust) is conferred by a genetic module: Pur1 and Exo70FX12, which are together necessary and sufficient. Pur1 encodes a leucine-rich repeat receptor kinase and is the ortho-log of rice Xa21, and Exo70FX12 belongs to the Poales-specific Exo70FX clade. The Exo70FX clade emerged after the divergence of the Bromeliaceae and Poaceae and comprises from 2 to 75 members in sequenced grasses. These results demonstrate the requirement of a lineage-specific Exo70FX12 in Pur1-mediated immunity and sug-gest that the Exo70FX clade may have evolved a specialized role in receptor kinase signalin

Implementation and Characterization of Vibrotactile Interfaces

While a standard approach is more or less established for rendering basic vibratory cues in consumer electronics, the implementation of advanced vibrotactile feedback still requires designers and engineers to solve a number of technical issues. Several off-the-shelf vibration actuators are currently available, having different characteristics and limitations that should be considered in the design process. We suggest an iterative approach to design in which vibrotactile interfaces are validated by testing their accuracy in rendering vibratory cues and in measuring input gestures. Several examples of prototype interfaces yielding audio-haptic feedback are described, ranging from open-ended devices to musical interfaces, addressing their design and the characterization of their vibratory output

Cacopsylla pyri L. (Hom., Psyllidae) and its predators relationship in Italy's Emilia-Romagna region

Sampling techniques for Cacopsylla pyri adults and its predators (Anthocoris nemoralis, Coccinellidae spp. and Chrysopidae spp.) were comparatively studied over autumn-winter 2000 in three pear orchards of Ferrara Province in northern Italy's Emilia-Romagna Region. Bating tray (or frappage), yellow sticky traps and corrugated cardboard traps were employed for insect monitoring while water pan traps were used for the phenological timing of leaf fall. The beating tray provided a more representative sampling method to evaluate the population dynamics and density of C. pyri and its predators than the yellow sticky traps; the corrugated cardboard proved a reliable tool to assess the predator population dynamic in overwintering refuges. Along with climate (temperature) and plant physiological (leaf fall) data, the results reported provide useful information for the scheduling of winter treatments, also in case to control the spread of the mycoplasma-like organism (pear decline) in spring

Studies on side effects of some insecticides on aphid-feeding Coccinellidae in Emilia-Romagna fruit crops

The effects of six insecticides on adults of the aphidophagous coccinellids Adalia bipunctata (L.), Coccinella septempunctata (L.) and Oenopia conglobata (L.), were evaluated in field studies in apple, pear and peach orchards. The insecticides (and some of their different formulations) evaluated were the organophosphates (OP) chlorpyrifos, chlorpyrifos-methyl, azinphos-methyl and malathion, the carbamate derived Methomyl and the Nereistoxin analogues Cartap. Azinphos-methyl was consistently toxic to coccinellids with between 76% and 90.5% mortality occurring in four studies. Chlorpyrifos EC resulted in mortality ranging from 40.2% (apples,1999) to 63% (peach,2001) over five studies. Chlorpyrifos WDG mortality ranged from 50.8% to 70% over three studies. Chlorpyrifos-methyl resulted in 31% mortality in apples in 1999 and 86.1% mortality in pears in 1998. Methomyl and cartap were evaluated in a single study in apples and resulted in 66.7 and 10% mortality respectively. Malathion was evaluated in a separate study and caused 43.5% mortality

Difesa dalla generazione svernante di Pandemis cerasana (Hb.) (Lepidoptera Tortricidae) su pero in Emilia-Romagna (II contributo)

Difesa dalla generazione svernante di Pandemis cerasana (Hb.) (Lepidoptera Tortricidae) su pero in Emilia-Romagna (II contributo

Mimic-Confirm (a. i. Tebufenozide): a tool for a soft and ecologically sound pest control in pear orchards

An investigation regarding the side-effects of two insecticide application strategies has been carried out. Two chemical control programmes for codling moth (Cydia pomonella L.) and for the main leafroller species (Pandemis cerasana Hb.) have been compared. One programme (“soft”) based exclusively on tebufenozide applications and the other one (conventional) based on traditional insecticides use (the exclusively use of tebufenozide was chosen only for experimental requirement, without considering the resistance management). The study has been carried out in the Ferrara District (Italy) on a pear orchard (cv. Abbè Fétel and Bartlett) in the 1998-99-00 years. A randomised block design with four replicates was used to compare the two different chemical control programmes. For sampling visual and inventory methods (depending from the insect species and the developmental stage) were used. The main pest species sampled were C. pomonella L., P. cerasana Hb., Cacopsylla pyri L. and Quadraspidiotus perniciosus (Comst.), while Anthocoris nemoralis (F.), coccinellids and syrphids were the beneficial ones. The results showed the reliability of the control strategy based on tebufenozide (no difference with regard to damaged fruits in comparison with the traditional one). This strategy gave smaller side effects on the beneficials, mainly regarding A. nemoralis young larvae. It has been possible to measure the lower insecticide use: both in quantitative and qualitative terms (toxicological classes)

Evidence of a female-produced sex pheromone in the European pear psylla, Cacopsylla pyri

Cacopsylla pyri (L.) (Hemiptera Psyllidae) is one of the most important pests of pear orchards in Europe that reduces the market value of pears. Summerform C. pyri males significantly preferred odours from living females or female cuticular extracts in the absence of visual stimuli in a Y-tube olfactometer. Conversely, males as well as females did not show any preference for odours from specimen of the same sex. Electroantennogram recordings showed that female cuticular extracts elicit dose-dependent responses in male antennae suggesting the presence of volatile compounds capable to stimulate the male peripheral olfactory system. Gas-chromatography coupled with mass spectrometry revealed marked quantitative differences between male and female cuticular extracts regarding 13-methylheptacosane, 11,13-dimethylheptacosane, 2-methylheptacosane, and 3-methylheptacosane. These compounds were found in larger amounts in female extracts which suggests their role in male attraction