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The population dynamics of Tetranychus urticae (two-spotted spider mite -- TSSM) are influenced by environmental factors, which were investigated to identify methods limiting the development and harmfulness of this pest. This paper presents findings from a laboratory study on the effect of spraying with water-based extracts of Mentha piperita and Tagetes patula plants on the growth rate of TSSM larvae and nymphs. The time required for the transformation of the larvae into protonymphs was longer for T. patula water- based extracts than extracts from M. piperita. Differences in the time of transformation from the nymphal stage to adult TSSM were also observed depending on the plant waterbased extracts, their concentration, and the host plant on which nymphs were developing. The use of 100 g · l-1 French marigold extract was associated with longer transformation time of nymphs on discs of pea leaves than all tested concentrations of French marigold extract applied to sugar beet leaves. Ten percent of the extracts from peppermint plants had a stronger limiting effect on TSSM nymphs on pea leaves than on bean or sugar beet leaves. [ABSTRACT FROM AUTHOR]

Ditylenchus destructor is a serious pest of numerous economically important plants worldwide. The population of this nematode species was isolated from the root zone of Ammophila arenaria on a Baltic Sea sand dune. This population's morphological and morphometrical characteristics corresponded to D. destructor data provided so far, except for the stylet knobs' height (2.1-2.9 vs 1.3-1.8) and their arrangement (laterally vs slightly posteriorly sloping), the length of a hyaline part on the tail end (0.8-1.8 vs 1-2.9), the pharyngeal gland arrangement in relation to the intestine (dorsal or ventral vs dorsal, ventral or lateral) and the appearance of vulval lips (smooth vs annulated). Ribosomal DNA sequence analysis confirmed the identity of D. destructor from a coastal dune. [ABSTRACT FROM AUTHOR]