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The methodology of integrated Colorado potato beetle management in potatoes under new agro-environmental conditions
Doležal, P. ; Hausvater, E. ; Baštová, P. ; Kocourek, F. ; Stará, J. ; Sedlák, P. ; Sedláková, V. ; Skoková Habuštová, Oxana ; Nermuť, Jiří
The aim of the certified methodology is to provide updated principles of effective integrated Colorado potato beetle management for the agricultural practice resulting from new findings on biology and population genetics in the situation, when the range of effective insecticides has been reduced, pest resistance to insecticides has been increased and agro ecological conditions have been changed. Colorado potato beetle is a very serious insect pest of potatoes, highly mobile and able to quickly develop insecticide resistance. The methodology was drawn up based on the newest findings on the efficacy of existing insecticides registered against Colorado potato beetle, taking into account newly acquired knowledge in the field of pest resistance to active ingredients and a necessity of ever increasing multiple applications.
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The complex characterisation of nematode Phasmarhabditis hermaphrodita
NERMUŤ, Jiří
Ph.D. thesis "The complex chacterisation of the nematode Phasmarhabditis hermpahrodita" is focused on the study of ecology of slug parasitic nematode P. hermaphrodita, its general characterisation in the context of all nowadays knowledge. The thesis consists the general introduction, that introduces the whole nowadays research of P. hermaphrodita, and four original works, that follow the introductory chapter. The first work deals with the orientation of P. hermaphrodita in 2D and 3D space and reaction on the presence of different hosts or nutritive substrates. The other study deals with the reaction of P. hermaphrodita on various animal and plant nutritive substrates and in the first place the influence of these substrates on the development of nematodes and quality and quantity of progeny. The third scope of this thesis is the influence of intraspecific competition on development, quality and quantity of nematodes and the last part of this text comprises a short study of the persistence of P. hermaphrodita in different substrates, from mineral to organic.
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The Influence of Pesticides on the Infectivity of Entomopathogenic Nematodes
NERMUŤ, Jiří
It is known that entomopathogenic nematodes rarely live in fields where pesticides and fertilizers are used. Because they are organisms with a high potential for biological and integrated pest control the thesis tried to determine the influence of pesticides on the infectivity and mortality of selected nematodes: Steinernema feltiae, S. arenarium and S. kraussei in water solution of some pesticides. The results are that preparations Vydate (a. i. oxamyl) and Sulka (a. i. sulphur) have the highest negative influence on both characteristics. These pesticides cause a mortality of 94.3 - 99.9 % and reduce infectivity by about 50 {--} 75 % (level 3). The following preparations may be identified as having higher potential for infectivity reduction: above all, Starane 250 EC (fluroxypyr), Sumithion super (fenithrothion), and Novozir MN 80 (mancozeb); on the other hand, Treflan 48 EC (trifluralin) significantly increases mortality. Another important observation is a fact that infectivity is significantly influenced only by concentration of pesticides, not by exposure time. During an experiment with enhacement of resistance to oxamyl (Vydate) I falling mortality and increasing infectivity of entomopathogenic nematodes were observed after five rounds.
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