Die Pflanzung bei den Altgriechen

Ohne Zusammenfassung     

Two-season study of the influence of regulated deficit irrigation and reflective mulch on individual and total phenolic compounds of nectarines at harvest and during storage

The influence of deficit irrigation (Deficit) and reflective mulch (Reflective) of Caldesi 2000 nectarines on the content of individual phenolic compounds was studied at harvest and during storage for 2, 4, and 6 weeks at 2 °C during two consecutive years (2007 and 2008). Individual phenolic groups in the edible fruit part consisted mainly of proanthocyanidins (200 mg/100 g fw), lower content of phenolic acids (17 mg/100 g fw), and minor content of flavonols (5 mg/100 g fw) and anthocyanins (1.2 mg/100 g fw). Deficit irrigation increased the content of total phenolics, including proanthocyanidins and phenolic acids, reaching similar amounts in both years. Sun-exposed fruit (upper part of canopy) showed higher content than shaded fruit (lower part of canopy). However, Reflective significantly increased the content of total phenolics, particularly phenolic acids and proanthocyanidins, of fruit located in the lower part of the canopy. During storage, Deficit and Reflective did not affect the content of phenolic acids, flavonols, and proanthocyanidins when compared to the content at harvest. Optimizing cultural practices can be a way to increase the phenolic content of nectarines.     

Mutations in the sodium channel associated with pyrethroid resistance in the greenhouse whitefly, Trialeurodes vaporariorum

BACKGROUND: Trialeurodes vaporariorum Westwood is an important pest of protected crops in temperate regions of the world. Resistance to pyrethroid insecticides is long established in this species, but the molecular basis of the mechanism(s) responsible has not previously been disclosed. RESULTS: Mortality rates of three European strains of T. vaporariorum to the pyrethroid bifenthrin were calculated, and each possessed significant resistance (up to 662‐fold) when compared with a susceptible reference strain. Direct sequencing revealed three amino acid substitutions in the para‐type voltage‐gated sodium channel (the pyrethroid and DDT target site) of bifenthrin‐resistant T. vaporariorum at positions previously implicated with pyrethroid or DDT resistance (M918L, L925I and T929I) in other related species. CONCLUSION: This study indicates that resistance to bifenthrin in T. vaporariorum is associated with target‐site insensitivity, and that the specific mutations in the sodium channel causing resistance may differ between localities. Copyright © 2012 Society of Chemical Industry     

A spatiotemporal study of bacterial community profiles associated with Atlantic bluefin tuna larvae,Thunnus thynnus L., in three Mediterranean hatcheries

During the first 2 years of larval rearing trials with Atlantic bluefin tuna, survival was a challenging issue. As bacterial colonization of the gut has been shown to play a key role for other species, we studied the profiles of the microbiota associated with individual larvae at different stages in three distant hatcheries. The Bacterial Community Profile (BCP) was quantified based on PCR‐DGGE analyses of partial amplicons from 16S rDNA. Considerable individual variability in BCP was observed before onset of feeding, and the BCP did not show regular fluctuation during ontogenesis. Microalgae were added to the rearing tanks in two of the three hatcheries, but it was not possible to distinguish the effect of location from the effect of algal addition on BCP. In one hatchery, the larvae were reared either with algal addition or in mesocosm, but due to high individual variability, no significant difference in BCP was detected between the two groups. It was hypothesized that this variability was caused by differences in health, physiological status and developmental stage of the larvae. A practical conclusion from the study is the need to analyse a considerable number of individuals to reflect statistically significant differences between the microbial communities associated with rearing groups.     

Efficacy of the pyrethroid alpha-cypermethrin against Bactrocera oleae populations from Greece, and improved diagnostic for an iAChE mutation

BACKGROUND: The most important pest of olive orchards worldwide is the olive fruit fly Bactrocera oleae (Gmelin). Its control in Greece has been based on organophosphates (OPs), but their intense use has led to the development of resistance. A test previously developed to monitor the trait may not be as robust as originally thought. The pyrethroid alpha-cypermethrin has recently been registered for bait sprays, as an alternative to OPs. RESULTS: The susceptibility of 20 B. oleae populations to alpha-cypermethrin was examined. Variation was observed in their response, with LD(50) ranging from 0.14 to 3.28 ng insect(-1) and resistance factors from 2.3 to 54.7. Resistance mechanisms were investigated. Cytochrome P450 monoxygenase activities showed an association with resistance. Sequences in the domain IIS4-IIS6 of the B. oleae para-type sodium channel were also analysed, but no resistance-associated mutations were identified. Finally, a novel diagnostic assay able to reliably monitor the frequency of the iAChE G488S resistance mutation was developed. CONCLUSION: This is the first attempt to evaluate the efficacy of alpha-cypermethrin against B. oleae from Greece. Data showed that it can be used effectively, but also highlighted the importance of continuous monitoring. The IIS4-IIS6 sodium channel region is the default area in which to look for resistance mutations if target-site resistance to pyrethroids arises. The application of the novel iAChE molecular diagnostic may facilitate the introduction of pyrethroids alongside OPs currently in use.     

Parasitism of <Emphasis Type="Italic">Psytallia concolor</Emphasis> (Hymenoptera: Braconidae) on <Emphasis Type="Italic">Bactrocera oleae</Emphasis> (Diptera: Tephritidae) infesting different olive varieties

Psytallia concolor (Szépligeti) is a koinobiont endoparasitoid of many Tephritidae larvae, including Bactrocera oleae (Rossi), and has been used in Mediterranean areas for biological control of olive fruit fly by inundative release. The present study evaluates the influence of olive fruit variety (Amfissis, Arbequina, Branquita de Elvas, Carolea, Kalamon, Koroneiki, Leccino, Manzanilla, Mastoidis, Moroccan Picholine and Picholine) on P. concolor parasitism efficiency and performance in the field during two successive years. The results showed that the percentage of parasitism was significantly higher (>30%) in Mastoidis and Koroneiki (light-weight varieties <1.5 g) than Leccino which has a medium fruit weight, followed by Amfissis, Moroccan Picholine, Picholine and Branquita de Elvas. Only Manzanilla among large weight varieties, exhibited high percentage of parasitization (42.72%) during 2013. The mean weight of the pupae (>4.21 mg) as well as the length of the developed adult parasitoids (>3.5 cm) in Mastoidis and Manzanilla were significantly higher than these individuals developed from other varieties such as Koroneiki and Kalamon. Finally, the optimal host fruit for P. concolor development seems to be Mastoidis variety with great biological parameters and percentage of parasitism.     

Molecular fingerprinting of a new Kiwifruit cultivar (cv. Tsehelidis) and comparative analysis with cv. Hayward according to physicochemical properties

“Tsechelidis” is a new kiwifruit cultivar of Actinidia deliciosa species that was developed in North Greece (Episkopi, Imathia) through collaboration between Farmaplant S.A and Department of Agriculture Crop Production and Rural Environment, University of Thessaly.