The protection of reforested areas against the large pine weevil Hylobius abietis is one of the greatest forest management challenges in many European countries. No information exists on the spatial distribution of this pest, which is necessary to assess its abundance and, consequently, to precisely estimate its threat to reforested sites. The aim of this study was to assess the spatio-temporal changes in the number of H. abietis beetles in reforested clear-cut areas (reforestations) and neighbouring Pinus sylvestris stands, from which these beetles are assumed to migrate to the reforestations. In this two-year study, baited traps were used to catch H. abietis beetles in the reforestations and neighbouring stands. The results revealed significantly more beetles in the neighbouring old stands (61–69 years) than in the young stands (5–11 years). The distribution of the beetles in both the old and young stands was inversely dependent on the distance from the stand edge. The large pine weevil migration to the reforestations was most intense in mid-May and early June. In May, most beetles were collected along the edges of the reforestations; in June, their distribution was more regular; and in July, the beetles were more abundant in the central part of the reforestations. These results allow H. abietis monitoring improvement, which is an important element of integrated forest protection.
This study estimates the efficacy of an attract-and-kill (A&K) technique to control the horse chestnut leaf miner, Cameraria ohridella Deschka and Dimic (Lepidoptera, Gracillariidae), an invasive insect pest of the horse chestnut, Aesculus hippocastanum L. (Hippocastanaceae). The A&K formulation was dispensed as 50 μl droplets of paste-like matrix, containing C. ohridella sex pheromone, (8E,10Z)-tetradeca-8,10-dienal (85% + pure; 0.16% w/w) and a fast acting contact toxicant, pyrocides (94% pure; 6% w/w), applied directly to the bark of the trees. It was tested in 2003 at rates of 30 and 45 droplets/tree at the Ostrobramska site and at rates of 30, 60 and 90 droplets/tree at the Woloska site in Warsaw, Poland, for the first insect generation. A set of untreated plots (0 droplets/tree) was established at each site as well. The treatment efficacy was estimated using two indices: (1) moth catches in pheromone traps and (2) the number of mines per leaf. Trap catches were significantly higher in the untreated plots than in the treated plots regardless of the application rate in all sites. However, there were no significant differences in leaf damage amongst all plots on each site. At the “Lazienki Krolewskie” park the attractiveness of two types of pheromone sources were compared: traps were baited with rubber septum lures or with A&K droplets. The catches of C. ohridella in traps baited with lures were lower than captures in A&K droplet-baited traps, but the difference was not significant. Possible reasons for the low efficacy of the A&K method in management of C. ohridella and reducing leaf damage are discussed.
Small banded pine weevil Pissodes castaneus is one of the most dangerous pests of Pinus sylvestris plantations and thickets. The lack of effective and environmentally safe methods of limiting the number of the pest justified to undertake the studies aimed at the laboratory and field evaluation of biological activity of entomopathogenic fungus Beauveria bassiana used to reduce the numbers of small banded pine weevil.In laboratory, the beetles were reared on the sections of fresh Scots pine twigs that were treated with five suspensions containing from 1 × 10 4 to 1 × 10 8 conidia of B. bassiana in 1 ml. During the 3-week rearing, insect mortality was determined and median lethal concentration LC 50 was calculated. The field treatments consisted of spraying 4-year-old P. sylvestris trees with two formulations of fungus containing 1 × 10 8 conidia ml −1 of suspension. Treatments consisted of spraying 4-year-old P. sylvestris trees with two fungus formulations containing 1 × 10 8 conidia ml −1 . High insecticidal activity of B. bassiana was found because the pathogen caused the death of 14-94% of P. castaneus beetles, LC 50 = 6.51 × 10 5 conidia ml −1. Field treatments did not result in the reduction of plant damage caused by small banded pine weevil; therefore, the spraying of trees with B. bassiana cannot be recommended to protect the young stands of P. sylvestris against pest.
The intraspecific variation of climate–growth relationships observed on provenance trials results from among–provenance differences in phenotypic plasticity. Temporal variation in radial growth synchrony among provenances may be modified by adverse climatic/biotic conditions such as drought or insect defoliation. However, these factors can potentially diminish provenance–specific growth reactions and, consequently, prevent the identification of provenances with the highest adaptive potential. Thus, understanding the influence of major biotic conditions on provenance–specific climate–growth relationships seems to be important to anticipate climate change. To determine provenance–specific growth patterns in relation to climate conditions (drought), seed production (reproductive effort), and insect defoliation in a common garden of Scots pine (Pinus sylvestris L.), we applied dendroecological techniques to time–series of tree–ring widths and basal area increments. The long–term records of seed production and insect outbreaks from the local Scots pine stands were used to explain the potential effect of biotic factors on the temporal dynamics of radial growth synchrony. During a period of favorable growth conditions, Scots pine provenances showed a decline in inter–provenance synchronicity in growth patterns, while during years affected by severe soil water deficit and insect defoliation, they manifested high uniformity in growth dynamics. The long–term trend in growth synchrony among P. sylvestris provenances depend on both abiotic and biotic environmental factors. This gains significance following an introduction of the appropriate selection of tree provenances for climate–smart forestry.
This article investigates the affi nity between the characters of Satan and Chaos in John Milton’s Paradise Lost. My aim is to show the connections between those characters that appear surprising in the light of Milton’s professed theodicy. On closer inspection certain contradictions become manifest, which may enable analysis of the epic not usually advocated by Miltonic criticism. I propose a fusion of more or less customary Paradise Lost’s criticism with 20th century’s existential philosophy exemplified by Nicolai Berdjaev.
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