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Biological control of weevils pests of agricultural crops


Author: Moldovan Anna
Degree:doctor of biology
Speciality: 03.00.23 - Biotechnology
Year:2021
Scientific advisers: Mihai Leşanu
doctor, associate professor (docent)
Ion Toderaş
doctor habilitat, professor, Institute of Zoology of the ASM
Institution: Institute of Zoology of the ASM

Status

The thesis was presented on the 25 February, 2021 at the meeting of the Scientific Council and now it is under consideration of the National Council.

Abstract

Adobe PDF document0.92 Mb / in romanian

Thesis

CZU

Adobe PDF document 9.40 Mb / in romanian
209 pages


Keywords

Sitona lineatus, Hypera postica, Protapion apricans, Curculionoidea, fungal microflora, biological control, Republic of Moldova

Summary

Structure of the thesis: introduction, 4 chapters, general conclusions and recommendations, bibliography of 533 titles, Annexes, 140 pages of main text, 66 figures, 10 tables. The research results have been published in 18 scientific publications.

Research goal: investigation of the fungal microflora of the Sitona lineatus L., Hypera postica Gyll. and Protapion apricans (Hbst.) pests (Coleoptera, Curculionoidea), selection of biological control agents and characterization of the physiological properties of native fungal strains for the local production of biopesticides and their application in agroecosystems.

Research objectives: isolation and identification of native strains of micromycetes from the microflora of the species S. lineatus, H. postica and P. apricans; investigation of S. lineatus, H. postica and P. apricans susceptibility to the infection with isolated fungal strains with potential for use as biological control agents; determining the insecticidal activity of the selected entomopathogenic fungal strains against target pests S. lineatus, H. postica and P. apricans; characterization of the particularities of growth and development of fungal strains with increased insecticidal activity under different environmental conditions to develop the procedure for obtaining the insecticidal preparation and application recommendations.

Scientific novelty and originality: in the microflora of the investigated curculionoid beetles, 55 fungal strains were highlighted, being identified at species level based on the molecular markers 18S rRNA gene sequence and ITS. For the first time, the presence of entomopathogenic fungi of the genera Beauveria and Isaria was detected in the microflora of S. lineatus and H. postica pest insects, on the territory of the Republic of Moldova. For the first time, the fungal microflora of the species P. apricans was investigated. The presence of phytopathogenic species in the fungal microbiota of insects involves the investigation of targeted pests as potential vectors. The fungal strain Beauveria bassiana CNMN-FE-01 showed increased insecticidal activity (MD 4560 patent), and advantageous properties for the formulation and application of bioinsecticides.

The result that contributes to solving an important scientific problem consists in: highlighting the new native fungal strains with insecticidal activity, selection of the strain with increased virulence, physiological and biochemical properties of technological importance, establishing the bioactive agent of the insecticide preparation which led to the elaboration of the procedure for obtaining and applying the bioinsecticide preparation and its integration into agricultural production systems.

Theoretical significance: new data were obtained on the fungal communities that constitute the microflora of pests of agricultural crops; pest species have been highlighted as potential vectors of phytopathogenic fungi emphasizing the importance of developing efficient and harmless methods of their control; the potential application of native strains of Beauveria bassiana as a bioactive agent for the local production of insecticide preparations has been scientifically argued; the procedure for obtaining the insecticide preparation intended for the biological control of curculionoid beetles has been proposed.

Applicative value: a process for obtaining a natural insecticidal preparation based on the new native strain of Beauveria bassiana CNMN-FE-01 is proposed for the biological control of the species Sitona lineatus. The strain showed promising physiological and biochemical properties that will allow the development of biopesticides and their wide application for the protection of Fabaceae crops.

Implementation of scientific results: the results are used as teaching material for training students in the specialties of Biology, Molecular Biology (bachelor's degree), Applied Biological Sciences (master's degree), in the training courses provided to trainers and farmers in the field of organic agriculture and biological methods of pest control.