Fosfitos no manejo alternativo da antracnose pós-colheita em pimentas do Nordeste brasileiro

• Autor(a) principal: ALEXANDRE, Elizabeth Rodrigues
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/7840
• topic: Antracnose; Colletotrichum; Controle alternativo; Pimenta; FITOSSANIDADE::FITOPATOLOGIA

The chilies are among the most important horticultural crops belonging to the Solanaceae grown in Brazil. The species and varieties that are known nation wide are also grown in the Northeast region, with greater volume for ‘Malagueta’ and ‘Tabasco’ in addition to the varieties ‘Biquinho’, ‘Dedo-de-moça’ and ‘De Cheiro’ that are distributed throughout the region. As a horticultural crop, the chili has a short post-harvest life that may be reduced when affected by post-harvest anthracnose. Species of Colletotrichum are associated to the disease compromising the viability of the fruits for consumption and commercialization, as they depreciate it. The management for the disease is difficult and there are no registered fungicides for post-harvest disease. In view of the above, we sought to evaluate the effects of phosphites as an alternative control strategy for Colletotrichum anthracnose on the main chilies cultivars found in the Brazilian Northeast, evaluating the attributes: physical-chemical, bark coloring and biochemical, structural analysis light microscopy and scanning electron microscopy (MEV) of post-harvest treated chilies and the effect of applied products on preharvested chilies. In the first chapter, the effect of phosphites Phi Ca, CaB, K, Cu, Zn and Mg and salts GRAS (NaHCO3, CaCl2,NaCl and KCl) on these chilies were evaluated under the incidence of quiescent and under post-harvest quality through the evaluation of physicalchemical and biochemical attributes under storage conditions at 12 ° C, 15 ° C and 25 ° C. It was found that GRAS and Phi Zn and Mg salts, although not compromising the total soluble solids (ST) content, total titratable acidity (AT), pH and ascorbic acid, reduced the incidence of fungi of the genus Lasiodiplodia, Fusarium and Colletotrichum. Phi Ca and CaB promoted the highest inhibition of the incidence of quiescent infections, and among the phosphites used in the biochemical evaluation, these phosphites in the concentrations of 0.5 and 1.0 gL-1 exerted increased activity of the catalase and ascorbate peroxidase enzymes in the fruits, and no effect on polyphenoloxidase activity. In the second chapter, the effect of the phosphites on the reduction of the post-harvest anthracnose was evaluated. In vitro, the Ca, CaB, K and Cu (0, 0.25, 0.5, 0.75, 1.0 , 1.25, 1.5 and 1.75 gL-1) were effective at reducing mycelial growth of Colletotrichum scovillei, where concentrations less than 1.0 g a.i L-1 were required for EC50, with the Phi K, Ca and CaB. In vivo the effect on the reduction of anthracnose, content of the elements (Ca, K, B and Cu) in the chilies after treatments, the physical-chemical attributes, the shell coloration and the structure of the tissue under light microscopy were evaluated. These phosphites in the concentrations of 0.5 and 1 g.L-1 showed different behavior in the different cultivars, on the reduction of the anthracnose by C. scovillei, C. truncatum and C. tamarilloi, with the most promising calcium-based phosphites for disease management, as the peptide endocarp structure remained intact when compared to untreated tissue, especially the Ca base, which improved the anthracnose. In general, the treatments did not alter the physicalchemical attributes and the color of the shell. In the third chapter, the effect of Phi Ca, Phi CaB and Phi K was analyzed in the pre-harvest phase of the ‘Dedo-de-moça’ and ‘Malagueta’ chilies in the years 2016/2017 on the reduction of post-harvest anthracnose from natural infection in the field. The products reduced post-harvest disease incidence and the calcium and potassium contents in the fruits were increased in relation to the control. The analysis of MEV showed that the tissue of the chili treated in post-harvest were shown to be intact. The phosphites have the potential to be used along with other management strategies in the control of chili anthracnose.