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| Author(s): |
Marcel Ricardo Tanzini
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2002-04-12 |
| Examining board members: |
Sergio Batista Alves;
José Eduardo Marcondes de Almeida;
Sergio de Freitas;
Paulo de Souza Gonçalves;
Sinval Silveira Neto
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| Advisor: | Sergio Batista Alves |
| Abstract | |
Studies on epizootiology were carried out in Pindorama-SP and Itiquira-MT, Brazil during two years. In Pindorama, in August 1998 an epizootic of Sporothrix sp. was observed in lacebug nymphs. In Itiquira, when the infestation reached 56 nymphs and 18 adults/leaf, a natural occurrence of Sporothrix sp. was observed, reducing significantly the pest population. Entomopathogenic fungi for use in lacebug control were selected from sixty isolates obtained from different hosts and applied to 4th instar nymphs. The best isolates were Beauveria bassiana (619 and 1196) with 56 and 84% mortality 3 days after the inoculation, Metarhizium anisopliae (1144 and 1104) both with 90%, S. insectorum (1229) with 92%, and Paecilomyces fumosoroseus (1200) with 100%. Trichoderma sp. caused 78% of mortality four days after inoculation. In field evaluations, the concentrations above 10 12 conidia/ha were efficient for control of the lacebug and the fungal isolates P. fumosoroseus (1200), B. bassiana (447) and M. anisopliae (1175 and 1144) were efficient for control of L. heveae. In the toxicity studies, the formulations Decis and Nuvacron were compatible with B. brongniartii (619). Most of the combinations, except for Decis, were compatible with Verticillium lecanii (972). M. anisopliae (1144) was very sensitive to all the formulations. Nuvacron and Stron were compatible with B. bassiana (1196), P. fumosoroseus (1200) and S. insectorum (1229). Marshal was compatible with B. bassiana (1196) and S. insectorum (1229), and Dipterex was compatible with P. fumosoroseus (1200). Two production methods and two culture media were evaluated for production of the fungi B. bassiana (1196), M. anisopliae (1189), S. insectorum (1229), P. fumosoroseus (1200) and V. lecanii (1200). The fungi P. fumosoroseus and B. bassiana were the most productive using the box method. In the tray method, B. bassiana was the most productive fungus. Between the production methods tested, V. lecanii was more productive in the tray method and P. fumosoroseus in the box method. Observations in Scanning Electronic Microscope LEO 435VP (SEM) revealed that, in general, all of the hyphomycetes had similar biological cycles on L. heveae, with adhesion, germination and beginning of the penetration within 24 h, vegetative growth between 48 and 72 h, and the extrusion and conidiogenesis of the pathogens by 96 h. (AU) | |