Banca de DEFESA: CLEIA DA SILVA LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : CLEIA DA SILVA LIMA
DATA : 23/11/2026
HORA: 08:00
LOCAL: Tangará da Serra
TÍTULO:

POTENTIAL AND COSTS OF BIOAGENTS IN THE CONTROL OF FUSARIUM WILT IN PINEAPPLE

PALAVRAS-CHAVES:

Ananas comosus var. comosus; Fusarium spp.; biological control; Trichoderma; Bacillus; economic profitability.

PÁGINAS: 114
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
RESUMO:

Pineapple fusariosis, mainly caused by Fusarium guttiforme, is one of the major phytosanitary problems affecting pineapple production in Brazil, causing yield losses and compromising fruit quality. Considering the limitations associated with chemical control, this dissertation aimed to evaluate the potential of biological control agents belonging to the genera Trichoderma and Bacillus for managing pineapple fusariosis, as well as to compare production costs and economic profitability between biological and chemical management systems. The research comprised three complementary studies involving in vitro assays, experiments with seedlings and fruits of pineapple (Ananas comosus var. comosus) cv. Pérola, and an economic analysis of the management systems. Initially, six Fusarium spp. isolates (CMU 28, 30, 31, 36, 115, and 116), originating from the Brazilian states of Mato Grosso and Bahia, were morphologically characterized according to macroconidial and microconidial dimensions, septation, and colony coloration on both the upper and reverse surfaces. Subsequently, an in vitro experiment was conducted using a completely randomized design in a 6 × 9 factorial arrangement, with four replicates, to evaluate the antagonistic activity of Trichoderma harzianum, T. asperellum, Bacillus subtilis, B. pumilus, and their combinations, including a bacterial consortium and a reference chemical treatment. Mycelial growth, percentage of growth inhibition, conidial production, and changes in colony coloration following confrontation with biological control agents were evaluated. Experiments were then conducted with pineapple seedlings and fruits using different biological treatments and experimental controls. In seedlings, inoculation was performed by immersion in a conidial suspension of Fusarium spp., and disease severity was assessed using a rating scale ranging from 0 to 5, along with the area under the disease severity progress curve (AUDSPC). For fruits, two experiments were conducted using different combinations of pathogen isolates, with inoculation performed using pathogen-colonized toothpicks and different biological agent application regimes. Disease development was assessed by measuring lesions at the inoculation sites. Experimental data were statistically analyzed according to the procedures established for each study, using Sisvar software for analysis of variance and mean comparisons, when applicable. The economic analysis followed a quantitative and documentary approach based on a structured data collection protocol, field records, and on-site observations. Production costs and profitability indicators were assessed for one hectare of pineapple cultivation in Tangará da Serra, Mato Grosso, Brazil. In the in vitro assays, T. harzianum showed the most consistent inhibition of Fusariumspp. mycelial growth, with inhibition rates exceeding 75% across all six isolates and reaching a maximum of 96.19% for isolate CMU 28. Treatments involving Bacillus spp. exhibited variable responses, including cases in which pathogen sporulation was stimulated. In seedling experiments, no statistically significant differences were detected among treatments, although the combination of T. harzianum and T. asperellum showed the lowest numerical means among biological treatments, with a mean disease severity score of 1.60 and an AUDSPC value of 38.00. In fruit experiments, lesion dimensions varied among treatments, without a consistent pattern of disease reduction by the biological agents. The economic analysis indicated that both management systems were profitable, with more favorable results for the biological management system, which achieved an operating profit of BRL 240,754.28 and a total unit production cost of BRL 1.07 per fruit. It was concluded that T. harzianum demonstrated antagonistic potential against Fusarium spp. under in vitroconditions. However, the results obtained from seedlings and fruits indicate the need for further studies to confirm the effectiveness of biological control agents under different growing conditions. The economic analysis, in turn, indicated greater profitability for the biological management system under the conditions evaluated, reinforcing the importance of integrating phytopathological and economic assessments when developing strategies for managing pineapple fusariosis.

MEMBROS DA BANCA:
Interna - 138379001 - DEJANIA VIEIRA DE ARAUJO
Interno - 118802007 - HILTON MARCELO DE LIMA SOUZA
Externa ao Programa - 40773001 - DAYANE CASTRO SILVA