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Browsing by discipline "Kasvintuotannon biologia (maatalouseläintiede)"

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  • Kangas, Niina (2013)
    The aim of this study was to look into the possibility of using predatory mites as a biological control agent in the nursery production. This study focuses on the biological control of two phytophagous mites, Tetranychus urticae and Aculus schlectendali that occur as pests in apple seedling production. The directive 2009/128/EY of the European Union obligates the farmers to follow the principles of the integrated pest management and favour other control methods, such as biological control, rather than chemical pesticides. This study is a part of The Finnish Nursery Producers Association’s project that aims to develop biological control practices for the nursery production in Finland and promote integrated pest management in nursery production. The experiments for this study were carried out outdoors in a field and indoors in a seasonal greenhouse, where the population development of T. urticae and A. schlechtendali on apple seedlings was followed. Population density of mites was counted from leaf samples gathered from the seedlings in two week intervals from May until the end of August. Biological control of T. urticae was tested with Phytoseeid mites, Neoseiulus barkeri and Phytoseiulus persimilis. Chemical control was used as a comparison treatment. The effects of the biological control were followed by comparing the population densities of phytophagous mites in the area of biological control to the mite densities in the area of chemical control. N. barkeri and P. persimilis were not able to prevent nor stop T. urticae population growth in the greenhouse where the densities of T. urticae grew higher in the area of biological control than in the area of chemical control. Outdoors the population densities of T. urticae remained low throughout the experiment in both treatment areas. Population densities of A. schlechtendali grew high indoors and outdoors within both treatments. Even though biological control did not succeed in these experiments, the conditions in the greenhouse were suitable for Phytoseeid mites and in theory it should be possible exploit them as control agents in nursery production. The high densities of A. schlechtendali were surprising. In the future it would be important to consider the importance of this species as a pest and find effective means to control it.
  • Rajanen, Hanne (2011)
    The forest industry achieves each year large quantities of waste material, such as wood, bark and branches. The waste material is mainly used for energy production, but new applications are being investigated. The bark has been identified as a potential source of numerous bioactive compounds, which would have use, for example, in the pharmaceutical and chemical industries as well as in the pest management of agriculture, forestry and horticulture. The thesis is part of the European Union-funded ForestSpeCs project, which aims to find alternative ways to use the materials of forest industry. The bark extracts of ten economically remarkable northern trees were tested for possibilities as antifeedants for the larvae of the cabbage white (Pieris brassicae L.), the Egyptian cotton leafworm (Spodoptera littoralis Boisduwal), and some of them also for the mustard leaf beetle (Phaedon cochleariae Fabricius) and the alder leaf beetle (Agelastica alni L.). The extracts were prepared in cooperation with the project groups or independently using different methods. Testing was carried out in laboratory conditions by using the dual-choice leaf-disc bioassays for the crude extracts and the individual compounds separated from them. The feeding deterrent indices (FDI) were calculated from the measurements. On the basis of the results, nearly all the tested extracts, at least to some extent, appeared to have an effect on the insect’s eating behavior. Slightly more than half of the 46 extracts tested with the cabbage white caused more than 50% feeding deterrence, in other words the cabbage butterfly preferred the control leaves more often than the treated ones. For Egyptian cotton leafworm larvae over 50% feeding deterrence was caused only by the seven of the tested 56 extracts. In addition, three of the extracts stimulated the consuming of the treated leaves significantly. The alder leaf beetle larvae and adults were deterred by the leaves treated with abietic acid, in particular. The extracts tested on the mustard leaf beetle were also working promisingly. It is possible to extract biologically active compounds from the bark of the tested tree species, but it is necessary, in the context of pest management, to have more research on the correct concentrations of the extracts and effective extracting methods. The quality and quantity of compounds in the bark depend on many factors, such as the impact of the environment and genetics. Tolerance in insects varies a lot by species and there are also differences between individuals. The pesticides manufactured of extracts could be possible to include in the integrated pest management alongside the other methods in the future.
  • Poutanen, Jari (2014)
    Gray mold (Botrytis cinerea) is an important disease of strawberry. The pathogen is spread by spores to strawberry flowers, from where the disease spreads to the developing berries. It progresses fast especially in high humidity and without any control. It can destroy even half of the crop. In conventional production, the strawberries have been sprayed by fungicides several times in beginning of summer. Only approved biological fungicides in Finland are Prestop- ja Prestop mix (Verdera Oy), and those can be spread to strawberries by honey bees (Apis mellifera), witch visits in the flowers of strawberry. For this task, the special additional equipment must been installed to hives. Inquiry survey have been made for the strawberry growers, witch have used the entomovectoring control method. The survey clarifies the problems of beginning to use the method, laboured and profitability, problems relating to bees and the needs of develop. Result of the survey is, that the growers have quite committed to use entomovectoring control method, even that many growers told that it was laboured and the efficency could not been seen clearly. The main reasons for the use of method were control of gray mold, reduce of chemical control and safety for user and environment. In addition to method gave image benefit to grower and improved pollination of strawberry. Getting started and use of method were more often trouble-free. The main development points were to extent the time between the addition of pesticide to the spreader equipment and to develop the method for commercial bumble-bee (Bombus terrestris) hives.