Abstract

GOMES, Ana; SAMPAIO, Ana; RODRIGUES, Paula  and  LARANJO, José Gomes. Field trials with fungicides and nutrient solution in chestnut trees: incidence of rots and Gnomoniopsis smithogilvyi in post-harvest nuts. Rev. de Ciências Agrárias [online]. 2023, vol.46, n.1, pp.51-60.  Epub Oct 24, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.27620.

Gnomoniopsis smithogilvyi is the main causal agent of chestnut brown rot in post-harvest nuts, a threat to the sustainability in the European market. With the objective of reducing the infection levels in chestnuts, the impact of commercial products application in G. smithogilvyi control was evaluated at the field. Trees with 8-years-old of the 'Bouche de Bétizac' variety were treated with Bacillus amyloliquefaciens, tebuconazol (2x in June and 1x in July), and silicon oxide (in June, July and August), applied by foliar spray. For biometric evaluation 120 burrs per treatment were collected, 200 chestnut nuts per treatment for external and internal evaluation and 10 chestnuts nuts per treatment for microbiological analysis, after 1 and 2 months of storage (4 ºC). In the biometric evaluation, the nutrient solution treated chestnuts had the best parameters. In the microbiological analysis and for all treatments, G. smithogilvyi was detected, except in the chestnuts treated with B. amyloliquefaciens or tebuconazole, at the harvest, and the ones treated with tebuconazole after 1 and 2 months of storage (4 ºC). B. amyloliquefaciens could be a substitute against some rots, and although it had some effect against G. smithogilvyi after harvesting, more research is needed on its ability to control this fungus. Tebuconazole activity against G. smithogilvyi lasted up to two months of refrigeration. However, with its withdrawal from the European market, biological control agents such as B. amyloliquefaciens, or similar, could be an alternative.

Keywords : chestnuts; chestnut rot; grove; tebuconazole; Bacillus amyloliquefaciens; silicon dioxide.

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