Development of a new bioinsecticde base on a Chrysodeixis chalcites nucleopolyhedrovirus from the Canary Islands
Chrysodeixis chalcites (Lepidoptera: Noctuidae) causes valuable economic damage in banana crops in the Canary Islands. Effective control of this pest with chemical insecticides requires many applications that increase production costs and render serious environmental hazards and chemical residues that hamper banana commercialization. In these situations, microorganism-based bioinsecticides, particularly baculoviruses, constitute one of the most realistic alternatives for efficient pest control programs. Under natural conditions, C. chalcites populations are affected by the C. chalcites nucleopolyhedrovirus (ChchSNPV) (Fam. Baculoviridae, Alphabaculovirus). The aim of this thesis has been to address seme of the biotechnological developments necessary to obtain a new biopesticide based on a ChchSNPV strain indigenous of the Canary Islands. Firstly, the genetic diversity of ChchSNPV in the Canary Islands was evaluated. During the course of a large field sampling, 97 larvae died with the typical signs and symptoms of NPV disease. These NPV isolates were grouped into five different strains as indicated by restriction endonuclease analysis of their viral DNA genome. The most widespread and prevalent isolate, ChchSNPV-TFI (ChchTFI), was also the most pathogenic and virulent against a local insect population. Genotypic characterization of this isolate revealed that ChchTF1 is composed of at least eight different genotypes, being ChchTF1-A the most isolated one and also the most prevalent in the wild-type population (36%). None of the pure genotypes was as pathogenic as the wild-type population, suggesting the occurrence of interactions among genotypes that increase the pathogenicity of the wild-type mixture. However, ChchTF1 was less virulent than single genotypes which was correlated with a higter occlusion body (OB) yield. ChchTF1 is genotypically structured to maximize its transmissibility in nature. Experimental testing mixtures of genotypes revealed that the co-occluded mixture composed by the three most prevalent genotypes, ChchTF1-ABC, in a proportion similar to that found in the wild-type population, was even more pathogenic than the wild-type population. Unexpectedly, the virulence of the co-occluded mixture was improved by 33 h in relation to the wild-type isolate.
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | tesis doctoral biblioteca |
| Published: |
Universidad Pública de Navarra
2014-01
|
| Online Access: | http://hdl.handle.net/10261/142440 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|