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Vliv prostorového rozmístění škůdců na růst a výnos řepky olejky =: The spatio-temporal distributions of pests in relation to growth and yield of winter oilseed rape /
Hlavjenka, Vojtěch
The within-field spatio-temporal distributions and relationships of cabbage stem weevil (Ceutorhynchus pallidactylus), pollen beetle (Brassicogethes aeneus) and cabbage seed weevil (Ceutorhynchus obstrictus) in a crop of winter oilseed rape were assessed in the Olomouc region over the course of 2014 – 2016. Distributions were analysed using SADIE analysis (Spatial Analysis by Distance IndicEs), and Quick Association Analysis was used for associations. A significant tendency towards aggregation of C. pallidactylus, B. aeneus and C. obstrictus was recorded on some sampling dates for all three years. The places with a non-random distribution, with higher and lower numbers of pests (patch and gap clusters), were located in different central and marginal zones of the fields. From the Quick Association Analysis a positive relationship was found between distributions of males and females of C. pallidactylus, males and females of C. pallidactylus × adults B. aeneus and adults of B. aeneus × C. obstrictus. Contrary to this, a mostly negative relationship was found between distributions of males and females of C. pallidactylus × adults of C. obstrictus. The spatial distribution of places with different lengths of stem injury caused by larvae Ceutorhynchus spp. as well as the distribution of places with different numbers of pods and seed yield was non-random in some years. A negative relationship was found between the distributions of females of C. pallidactylus during egg-laying period × distribution of places with different seed yield. In 2014 and 2015, a positive relationship was recorded between the dispersion of adults B. aeneus × distribution of places with different numbers of pods and seed yield. Contrary to this, in 2016, the relationship was negative. In 2015, a positive relationship was observed between the dispersion of adults C. obstrictus × distribution of places with different seed yield but in 2016 the relationship was negative.
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