788 research outputs found
Mating behavior and vibrational communication of the meadow spittlebug Philaenus spumarius
No full textAdieu au faux paradis, Film germano-turc de Tevfik Baser
No full textVideau André. Adieu au faux paradis, Film germano-turc de Tevfik Baser. In: Hommes et Migrations, n°1132, mai 1990. Les Africains Noirs en France. Deuxième partie : La vie culturelle. pp. 69-70
The effect of distance between parasitoid and host on the parasitism of Psyttalia concolor (Szépligeti) in organic olive orchards
No full textBactrocera oleae (Rossi) is a major pest of olive fruits. Biological control of olive fruit fly mainly relies on the activity of the Braconid species Psyttalia concolor (Szépligeti), which parasitizes Bactrocera oleae at the larval stage. Parasitism tests have been carried out at the insect growing facility (insectariums) of the Mediterranean Agronomic Institute of Bari (C.I.H.E.A.M.). The critical point of the use of P. concolor as a biological control agent in organic olive crop is the assessment of its effectiveness against B. oleae. Its lower presence in fruits of cultivated olives rather than in small fruits of wild olives suggests an influence of the size of the fruit, and of the thickness of its pulp on the parasitization of P. concolor. Therefore, the aim of this research was to investigate the capacity of the females of P. concolor to lay their eggs into the target host according to the distance existing between the female and the host larva. In these tests, the substitution host Ceratitis capitata was used and parasitism of P. concolor was tested at different distances (0, 0.5, 1, 1.5, 2, 2.5 and 3 mm) to the host larvae at different times (7 min, 15 min, 30 min and 60 min) of interaction.
Predetermined distances between the parasitoids and the target larvae were arranged by locating the flying females into cubical cages of 40x40x40 cm with Plexiglas walls and the open roof covered with a tulle tissue in order to avoid that any insects from outside may enter the cages, and to allow the females to protrude their ovipositors. On these roofs, plastic cylinders containing the target larvae were placed with the open bases arranged with a tulle tissue, to allow the contact with the parasitoid females. Considering the width of the tissues negligible, distances were set by metal separators with increasing thickness.
Parasitism level at 7 min was not significantly different at 2, 2.5 and 3 mm distances. Parasitism level was the highest at 0, 0.5, and 1 mm distances with no significant changes. Parasitism at 15 min showed a high variability according to the distances. The highest level resulted at 0.5 and 1 mm distances, the lowest at 3 mm distance. At 30 min interaction, the highest level of parasitism was at 0 mm distance, whilst at 1 and 1.5 mm the level was lower with no significant changes. Again, parasitism level was the lowest at 3 mm distance. The highest level of parasitism at 60 min was detected at 1.5 mm distance and was as lower as the distance increased.
In conclusion, the study showed that the females of P. concolor were not able to parasite the target larvae at distances higher than 2.5 mm. Generally, the parasitism level decreases with the increase of the distance between target larvae and parasitoid females. At the lowest distances (0, 0.5 and 1 mm) hyper parasitism occurred and the target pupae were killed, but also the development of the parasitoids into adults was very difficult for nutrient unavailability. Biological control of P. concolor against B. oleae larvae may give satisfactory results only if the depth at which the target larvae are located into the olive drupes is not higher than 2 or 2.5 mm from the surfac
Influenza delle caratteristiche chimico-fisiche del suolo e della gestione fitosanitaria sulla concentrazione di solfati in oliveti e vigneti biologici della Puglia
No full textKaurane diterpenoids from three Sideritis species
No full textSome kaurane diterpenoids were isolated from 3 species of the genus Sideritis (Lamiaceae) growing in the Eastern Mediterranean region. Sideritis libanotica subsp. libanotica contained siderol 2 and sideridiol 3. Sideritis erythrantha var. erythrantha yielded sideridiol 3. Sideritis perfoliata gave siderol 2, sideridiol 3 and sideritriol 4. The products are known as they occur in another species of Sideritis growing in Italy and in other species growing also in Turkey. The products are isolated for the first time from these 3 species. The taxonomic significance of these results is discussed
Composition of the essential oils of four endemic Sideritis species from Turkey
No full textSideritis phlomoides Boiss. & Bal., S. vulcanica Hub.-Mor,. S. vuralii Duman & Baser and S. caesarea Duman, Aytac & Baser are endemic species in Turkey. Water-distilled essential oils from the flowering spike of these plants were analysed by GCMS. beta -Pinens (35%). 1,8-cineole (15%) and alpha -pinene (15%) were the main component in the oil of S. vuralii. while beta -caryophyllene (8%) and caryophyllene oxide (7%) were the major constitutents in the oil of S.. caesarea. The oils from S. phlomoides and S. vulcanica tr were found to contain beta -caryophyllene (31% and 10%) as major constituents. alpha -Bisabolol (16%) was also found as a major component in the oil of Sideritis phlomoides. Copyright (C) 1999 John Wiley & Sons, Ltd
Behavioural responses of the egg parasitoid Trissolcus mitsukurii to the footprints of Halyomorpha halys and Nezara viridula
No full textTrissolcus mitsukurii is Asian egg parasitoids associated to different pentatomids such as Halyomorpha halys. Adventive populations of T. mitsukurii were found in Northern Italy showing a great impact on this pest, suggesting its exploitation as a biological control agent (BCA) against H. halys. Releasing an exotic parasitoid requires investigating the interaction BCA/environment, to avoid negative impacts on the entomofauna of the new habitat. Trissolcus mitsukurii is mainly associated to Nezara viridula in its native area, hence, we investigated the female parasitoid’s ability to distinguish between naturally released cues of H. halys and N. viridula and compared it with the foraging behaviour of Trissolcus japonicus. A single female parasitoid was exposed to contact kairomones of both pests, to evaluate its modifications in orthokinetic and locomotory behaviour. Additionally, for T. mitsukurii, synthetic compounds simulating the cues of the two pentatomids were used. The results confirmed the preference of T. japonicus for H. halys while T. mitsukurii preferred N. viridula’s cues. The significance and consequences of these results in the biological control of H. halys in invaded areas are discusse
Attraction of Egg Parasitoids Trissolcus mitsukurii and Trissolcus japonicus to the Chemical Cues of Halyomorpha halys and Nezara viridula
No full textTrissolcus mitsukurii and Trissolcus japonicus are two Asian egg parasitoids associated with different pentatomids such as Halyomorpha halys. Adventive populations of T. mitsukurii were found in Northern Italy, suggesting its employment as a biological control agent (BCA) against H. halys. Nevertheless, to reduce the latter’s population, T. japonicus was released in Italy. Releasing an exotic parasitoid requires investigating the interaction between the BCA and the environment to avoid negative impacts on the entomofauna of the new habitat. Trissolcus mitsukurii is mainly associated with Nezara viridula in its native area. Therefore, we investigated and compared the ability of female T. mitsukurii and T. japonicus to distinguish between naturally released cues of H. halys and N. viridula. A single parasitoid was exposed to contact kairomones of both pests to evaluate its modifications in orthokinetic and locomotory behaviour. The behaviour of female T. mitsukurii was also tested on synthetic compounds simulating the cues of the two pentatomids. When naturally released cues were used, T. japonicus preferred the traces of H. halys, while T. mitsukurii preferred N. viridula’s cues. Moreover, the attraction of T. mitsukurii to N. viridula’s cues was confirmed with synthetic cues. Additional studies are needed to judge if this parasitoid can be used as a BCA
Monitoring of Soil Copper Concentrations in Different Organic Farms over a Three-Year Period in Apulia, South-Eastern Italy
No full textCopper is considered as a cornerstone of grapevine downy mildew and olive fly management in Apulian organic farms in particular and in the Mediterranean area in general. In this work we studied the influence of soil properties, cultural practices, and pest management strategies on copper concentrations and accumulation in organic vineyards and olive groves of Apulia (south-eastern Italy). In 2005, 2006, and 2007 about 70 soil samples were collected from 13 organic olive groves and vineyards at 0-0.2 m and 0.2-0.4 m depths in five Apulian organic farms representing a wide range of soils physicochemical properties. Results of physical and chemical analyses, carried out in 2005 and 2007, highlighted notable differences between soil samples in terms of total carbonate, clay, and organic matter contents, while pH values were very similar. Copper input in 2004, 2005, and 2006 ranged from 7.6 to 46.8 kg/ha. Total copper concentrations, determined in 2005, 2006, and 2007 with ICP-OES, showed a moderate Cu accumulation, higher in the shallow layer than in the subsoil and in vineyards than in olive groves in all the sampled farms and for both sampling layers. Cu accumulation increased with increasing copper-based treatments number and application rates, and also with increasing pHH2O, clay, and organic matter. Copper availability was higher in the shallow layer than in the subsoil and in vineyards than in olive groves especially in 0-0.2 m layer. Results showed that copper has a medium accumulation in Apulian soils, therefore regulations limiting its use (i.e. CR 473/2002) should be rigorously applied and its alternatives use should be encouraged in order to minimize possible long term effects on soils
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