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In accordance with the National Program for Increasing Forest Cover it is planned to augment Poland’s forest cover to 30% by 2020. This task involves afforestation of agricultural lands by pioneer species that have low habitat requirements, such as the silver birch or the Scots pine. Application of sawdust, clear cutting residues, compost bark and compost beneath tree roots contributed to better development of the assimilation apparatus. The use of mineral fertilizer stimulated tree growth as well as improved physical and chemical properties of soil.
The pine processionary moth, Taumetopoea pityocampa (Denis and Schiffermüller) is one of the most widespread defoliator insects found in the forest areas of Turkey. Although different methods have been used to control this major forest pest up to now, the problem is still going on largely unsolved in the forest areas of Turkey. The objective of this study was to determine larvicidal effects of extracts obtained from six different plant species, Achillea wilhelmsii C. Koch, Nepeta meyeri Benth., Satureja hortensis L., Origanum onites L., O. rotundifolium Boiss., Tanacetum argyrophyllum (C. Koch) and on the 2nd, 3rd, and 4th instar larvae of T. pityocampa in laboratory conditions.Test the toxicity of six plant extracts against to the 2nd, 3rd, and 4th instar larvae of T. pityocampa, 10 larvae of this insect with 15 gr amounts fresh needles (1 year old) of Pinus brutia were placed to Petri dishes (9 × 1.5 cm deep). Each dose was dissolved in acetone and 0.25, 0.5 and 1 mg of the plant extracts found in 1 ml solution were sprayed on the 2nd, 3rd, and 4th instar larvae of T. pityocampa in the Petri dishes, corresponding to 2.08, 4.16 and 8.33 mg·l -1 air concentrations. Petri dishes were covered with a lid. All tests carried out at 26ºC (±2), 60% (±5) relative humidity and 14/10 h light/dark photoperiod in laboratory conditions. When exposure, mortality of the larvae was after the determined at 24, 48 and 96 h. Petri dish applied with sterile water and acetone were used as control group. All the tests were made in triplicate. The results showed that six plant exracts have a larvicidal effect on the 2nd, 3rd, and 4th instar larvae of T. pityocampa in comparison with controls. Therefore, these naturally occurring plant extracts could be useful for managing the larvae populations of T. pityocampa.
The article presents the attempt to establish connections between the shape of cones and the weight, number and colour of seeds coming from one stand. The author suggested choosing pine (Pinus sylvestris) seeds of the best cultivation characteristics before extraction, paying attention to the shape of cones, and after extraction basing on the weight and colour of seeds. In addition, the author studies the distribution of dark and light seeds on cone scales.
Two-year needles were collected from 42 trees from 5 localities in Spanish Pyrenees. The needles were analysed in respect to 15 morphological and anatomical traits. Data obtained were subject of multivariate statistical analyses. The most stable traits appear to be width of epidermis cells, width and thickness of the needles and ratio of the last two characters. Number of the resin canals and the vascular bundles distance were the most variable characters. The differences among the 42 investigated trees are not evident, considerably small and not significant statistically.
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