Long-term studies on the evolution of resistance of (Hemiptera: Aphididae) to insecticides in Greece.

The aphid Myzus persicae s.l. (Hemiptera: Aphididae) is an important pest of many crops worldwide with a complex life cycle, intensely controlled by chemical pesticides, and has developed resistance to almost all used insecticides.

Comparing the genetic structure of codling moth Cydia pomonella (L.) from Greece and France: long distance gene-flow in a sedentary pest species.

Codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) is the most important insect pest of apple production in Europe. Despite the economic importance of this pest, there is not information about the genetic structure of its population in Greece and the patterns of gene-flow which might affect the success of control programs.

A small deletion in the olive fly acetylcholinesterase gene associated with high levels of organophosphate resistance.

Organophosphate resistance in the olive fly was previously shown to associate with two point mutations in the ace gene. The frequency of these mutations was monitored in Bactrocera oleae individuals of increasing resistance. In spite of the difference in resistance among the individuals, there was no correlation between mutation frequencies and resistance level, indicating that other factors may contribute to this variation.

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.

Insecticide resistance status of Myzus persicae (Hemiptera: Aphididae) populations from peach and tobacco in mainland Greece.

The susceptibility of 88 and 38 field samples of Myzus persicae (Sulzer) to imidacloprid and deltamethrin respectively was examined using the FAO dip test bioassay. The field samples were collected from tobacco and peach from various regions of Greece in the period from 2004 to 2006. In addition, 497, 349 and 370 clones originating from peach and tobacco were screened for the three known resistance mechanisms, elevated esterases, modified acetylcholinesterase (MACE) and knockdown resistance (kdr) respectively, using biochemical and DNA diagnostics.

Genetic variation among Mediterranean populations of Sesamia nonagrioides (Lepidoptera: Noctuidae) as revealed by RFLP mtDNA analysis.

Restriction fragment length polymorphism analysis of two segments of mitochondrial DNA (COI and 16S rRNA) was used to examine genetic variation in Sesamia nonagrioides (Lefèbvre) populations from the Mediterranean basin. Four populations were collected from central and southern Greece, and five from northern latitudes: Greece, Italy, France and Spain. No variation was observed in COI, while 16S rRNA segment proved highly polymorphic and 28 different haplotypes were found.

Distribution of common genotypes of Myzus persicae (Hemiptera: Aphididae) in Greece, in relation to life cycle and host plant.

Microsatellite genotyping was used to identify common clones in populations of the Myzus persicae group from various hosts and regions in mainland Greece and southern Italy and to compare their distribution and occurrence on tobacco and other crops. Common clones were defined as genotypes collected at more than one time or in more than one population; and, therefore, unlikely to be participating in the annual sexual phase on peach. Sixteen common genotypes were found, accounting for 49.

Organophosphate resistance in olive fruit fly, Bactrocera oleae, populations in Greece and Cyprus.

The olive fruit fly Bactrocera oleae (Gmelin) (Diptera: Tephritidae) is the most important pest of olives in countries around the Mediterranean basin. Its control has been based mostly on bait sprays with organophosphate insecticides (usually dimethoate or fenthion) for about 40 years. In the present study, the resistance status of olive fruit fly populations to dimethoate was examined in Greece and Cyprus over 2 years.

Transmission of Potato virus Y in Tobacco Plants by Myzus persicae nicotianae and M. persicae s.str.

The transmission efficiency of Potato virus Y (PVY) from and to tobacco plants by Myzus persicae nicotianae, a tobacco specialist, and M. persicae s.str.

Morphological discrimination of Aphis gossypii (Hemiptera: Aphididae) populations feeding on Compositae.

Aphis gossypii Glover is a polyphagous aphid pest with a worldwide distribution. However, there is evidence that on a global scale the name A. gossypii is being applied to a number of forms with different life cycles and/or host-plant associations.

Discrimination of the closely related biocontrol agents Macrolophus melanotoma (Hemiptera: Miridae) and M. pygmaeus using mitochondrial DNA analysis.

The separation of the closely related predatory species Macrolophus melanotoma Costa (= M. caliginosus Wagner) and Macrolophus pygmaeus (Rambur) based exclusively on the different colour pattern of the first antennal segment (white central band in M. melanotoma and entirely black in M.

Genetic variation of Marchalina hellenica (Hemiptera: Margarodidae) sampled from different hosts and localities in Greece.

Random amplified polymorphic DNA (RAPD) analysis was applied to 120 individuals of Marchalina hellenica (Gennadius) representing six populations collected in northern, central and southern mainland Greece. One population was sampled on one species of fir tree and the others on two species of pine trees. Four random decamer primers were used to evaluate genetic variation among the populations examined.

Performance of Myzus persicae (Hemiptera: Aphididae) clones on different host-plants and their host preference.

The performance of eighteen clones of Myzus persicae (Sulzer) on pepper and tobacco plants at 20 degrees C and L16:D8 and the choice of young adult apterae between tobacco and pepper leaf-discs were examined. The clones were collected from weeds and peach in two tobacco-growing regions: Katerini, northern Greece and Karditsa, central Greece (only from weeds) and from Lehonia, central eastern Greece where tobacco is not cultivated. All clones did well on both hosts.

Co-existence of different host-adapted forms of the Myzus persicae group (Hemiptera: Aphididae) in southern Italy.

Multivariate morphometric analysis (method of canonical variates) was used to compare 38 parthenogenetic lineages and three field collections of aphids of the Myzus persicae (Sulzer) group sampled on peach and tobacco in the Caserta region of southern Italy. Comparisons were also made with the morphology of lineages collected on peach in Lehonia, in central eastern Greece away from tobacco-growing regions, and on tobacco in Naphplion, in southern Greece. The lineages were measured after parthenogenetic rearing for one to three generations on the same host (potato) under constant conditions.

Biological characteristics of the mirids Macrolophus costalis and Macrolophus pygmaeus preying on the tobacco form of Myzus persicae (Hemiptera: Aphididae).

Biological and population parameters of the predatory bugs Macrolophus costalis Fieber and Macrolophus pygmaeus Rambur preying on the tobacco aphid Myzus persicae (Sulzer) were examined. Tobacco was used as host plant and all experiments were carried out at 23 degrees C and L16:D8. In M.

Production of sexual morphs by apterous virginoparae of Myzus persicae (Hemiptera: Aphididae) in relation to pre- and postnatal exposure to short day conditions.

The production of males and females by apterae of a holocyclic clone of Myzus persicae (Sulzer) was studied in the laboratory by transferring apterous virginoparae from long day to short day conditions at different stages of their pre- and post-natal development. Prenatal exposure was also examined in nine additional clones coming from different regions of Greece. By increasing the number of short day cycles at 17 degrees C, the aphids switched to male production earlier and produced more males.

Life cycle variation of Myzus persicae (Hemiptera: Aphididae) in Greece.

During the years 1995-1999 the life cycle category of 2797 clones of Myzus persicae (Sulzer) was examined. The clones originated from primary and secondary hosts from different localities of North and Central Greece and the island of Crete in the south. Four different overwintering life cycle strategies were found that have also been described for M.

Variation in the life cycle and morphology of the tobacco host-race of Myzus persicae (Hemiptera: Aphididae) in relation to its geographical distribution.

Morphological variation and life cycle category were examined in 121 clones of Myzus persicae (Sulzer). The clones were collected from tobacco from three localities in Greece (Xanthi, Nea Efessos and Naphplion), one in Germany (Rheinstetten), one in France (Bergerac) and one in Spain (Madrid). Before morphometrics, all aphids were laboratory-reared on potato.

A modified method for the detection of differentially expressed mRNAs without using radioactivity.

We present here a modification of the original differential display approach using a single oligo(dT) primer for the reverse transcription reaction (instead of the various oligo(dT)NM primers that subdivide the pool of mRNAs) and a combination of 25-mer or 26-mer arbitrary primers together with 30-mer anchored primers for the PCR reaction. The PCR products are, then, efficiently separated in a non-denaturing polyacrylamide gel and the bands are visualized after staining with silver nitrate. The model for the development of our differential display approach was seven clones of an insect species: the aphid Myzus pesicae (Sulzer) (Homoptera: Aphididae).

Host-correlated morphological variation of Myzus persicae (Hemiptera: Aphididae) populations in Greece.

Morphological variation in nine characters of 157 clones of Myzus persicae (Sulzer) was examined by multivariate analysis. The clones were collected from peach, Prunus persica, the primary host and the secondary hosts tobacco, Nicotiana tabacum, cabbage, Brassica oleracea, sugarbeet, Beta vulgaris and pepper Capsicum annuum. The 156 clones originated from various regions of Greece, both in the north, where a large part of the population has an annual bisexual generation on peach, and in more southerly regions, where populations are predominantly unisexual.