Description: Das Projekt "Effizienzsteigerung beim Einsatz von Bacillus thuringiensis Berliner zur Bekaempfung wirtschaftlich bedeutsamer Forstschaedlinge" wird vom Umweltbundesamt gefördert und von Technische Universität München, Forstwissenschaftliche Fakultät, Lehrstuhl für Angewandte Zoologie durchgeführt. 1. Influence of the different diets in the biological cycle of the insects. - Depending on the diet the larvae of Lymantria monacha show not only different time to complete their biological cycle but also different percentage of mortality as well as different capacity of reproduction in laboratory. The best results for the completion of the biological cycle were obtained on pine needles where insects took approximately 8 weeks to complete it. In artificial diet the insects not only have a longer biological cycle but also the amount of eggs and its fertility decreased tremendously after the third generation. The development on oak acorn did not give good results for rearing in laboratory. 2. Influence of the diet in bioassays with biopesticides.- The toxicity of different doses of B.t var. kurstaki was tested in third instar larvae of Lymantria monacha reared on two different diets: artificial and natural (pine needles). Different doses (IU/larva) of B.t. were given to the insects to find out the level of toxicity for this insect. The pesticide used was Dipel WP which has 3,2 percent Bacillus thuringiensis Berl. and 16,000 IU in 1mgr/ml. Each doses was tested on 40 larvae fresh molted to L3 stadium and they were observed for 6 days. Results show that there are big differences for the control depending on the diet used. So, the LD5O for insects on artificial diet is the 18,7 IU/larvae while for insects fed on natural food (pine needles) was 39,5. At cellular level sing immunofluorescens technique showed that after one hour of the infection with B.t., insects that were fed on pine needles did not have toxins bound to midgut receptors, at the contrary to those fed on artificial diet. Also the measurement of the pH in the guts of the insects show that for those fed on art. diet had a favorable pH (9,5-11) for the dissolution of the B.t crystals. This explain why B.t. is so effective to small little doses for this insects in comparison to the others fed on pine needles. 3. Biotests. The relation between the analysis of the different pine fractions and different B.t. doses shows that there is a fraction in the pine needles which amount of phenols interfere with the crystal protein (toxic substance) of the B.t.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: München ? Eiche ? Kiefer ? Phenol ? Insekt ? Bayern ? Pestizid ? Larve ? Bacillus thuringiensis ? Berlin ? Sportanlage ? Zoologie ? Bacillus ? Nonne ? Toxin ? Forstschädling ? Biotest ? Dosis ? Parasit ? Ei ? Mortalität ? Toxische Substanz ? Toxizität ? Biologische Schädlingsbekämpfung ? Insektenbekämpfung ? Auflösen ? Fruchtbarkeit ? Kausalanalyse ? Züchtung ? Ernährung ? Infektion ? Pflanzeninhaltsstoffe ? Lymantria-monacha ?
Region: Bayern
Bounding box: 12.53381° .. 12.53381° x 47.795° .. 47.795°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1993-10-01 - 1995-09-30
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