Elicitors on the control of anthracnose and post-harvest quality in papaya fruits1

<div><p>ABSTRACT Papaya is one of the most grown and consumed fruits in the world. However, post-harvest diseases are responsible for more than 50 % of losses, including anthracnose, caused by Colletotrichum gloesporioides, which promotes necrotic and rounded lesions and reduces fruit quality. Alternative products have been widely investigated in the control of pathogens. This study aimed at evaluating the efficiency of elicitors in the control of anthracnose, as well as their effect on post-harvest quality, in papaya fruits. The fruits were disinfested and immersed in acibenzolar-S-methyl, potassium phosphite, Rocksil®, Agro-mos®, Ecolife®, sterilized distilled water and prochloraz, inoculated with C. gloesporioides and stored. Potassium phosphite, Rocksil®, Ecolife® and prochloraz resulted in the smallest diameters of lesions, and, consequently, in a greater protection and enzymatic activity. The fruits treated with Rocksil® and Ecolife® maintained the lowest levels of soluble solids and titratable acidity. Potassium phosphite, Rocksil® and Ecolife® are effective in controlling anthracnose, do not change the appearance and preserve the post-harvest quality of papaya fruits, and, therefore, may be used as an alternative to commercial fungicides.</p></div

Alternatives in the control of Alternaria brown spot in ‘Dancy’

<p></p><p>ABSTRACT The tangerine ‘Dancy’ has desirable characteristics such as color, aroma, flavor and wide acceptance by the market. This variety is highly produced in the state of Paraíba but is susceptible to Alternaria brown spot (MMA), caused by Alternaria alternata, responsible for compromising the fruit quality in tangerine producing regions. To prevent this disease, research using alternative products has been expanded. Therefore, the objective of this study was to determine the potential of the extract of Caesalpinia ferrea and Chitosan® in the management of MMA in fruits of ‘Dancy’ tangerine. The fruits were disinfested and immersed in extract of C. ferrea at concentrations of 0, 10, 100, 500 and 1000 µg/mL, and Chitosan® at 0.5, 1.0, 1.5 and 2.0 g/L. After 24 h of the application of products, the fungus A. alternata was inoculated (105 spores/mL). From the second day after inoculation (DAI), severity (AUDPC) was daily evaluated. For analysis of the activities of phenylalanine ammonia-lyase, peroxidase and polyphenol oxidase, three fruits/replicate were taken on the first and twelfth days of the experiment. The design was completely randomized including 9 treatments (concentrations of products) and 5 replicates with 5 fruits, which constituted an experimental unit with 225 fruits. Regression analysis and Dunnett’s test (P ≤ 0.05) were performed by using SAS® System 9.3 software. The concentrations of 500 µg/mL of C. ferrea extract and 1.5 g/L Chitosan® reduced the severity of Alternaria brown spot and promoted high activities of the enzymes in ‘Dancy’ tangerine fruits.</p><p></p