Safe postharvest treatment with protective effect in oranges inoculated with Penicillium digitatum

VALERIA CARINA BORDAGARAY; LAURO BORDENAVE IMER; MARÍA JULIETA BOF; GUSTAVO DANIEL SUAREZ; DELIA ELISA LOCASO

Bari

Simposio; III International Symposium on Postharvest Pathology; 2015

The protective effect of antifungal treatments in citric fruits has been evaluated opposite to conventional fungicides of chemical synthesis, a substitute to conventional treatments has evaluated, since its negative effects on health and environment, both fungicides and residues. Untreated Valencia oranges, export quality, were obtained from a citrus packhouse in the Entre Ríos, Argentina. Two coatings -coatQ1 and CoatQ2- with different concentrations of fatty acids C24 / C16 and chitosan were tested against fruit treated with Imazalil - 250 μg.mL-1 - and commercial wax with 18 % solids , as a positive control (C); and uncoated fruit as a control (T). The application of the coatings was carried out in two layers in a line of industrial packhouse. For the first treatment, A1 the fruit was treated with coatQ1 and then with coatQ2; on the second treatment, A2 the order of application was interchanged. All the fruits were inoculated with 10 µL of a suspension of 106 spores.mL-1 of Penicillium digitatum , and stored for 10 days at 25 °C and 95% RH . The strain used was isolated from fruits affected by the disease obtained from the region. The efficacy of the disease control of was expressed as percentage of reduction in the number of infected fruit compared to the fruits used as a control. Aditionally, the infection index was used to quantify the surface of the fruit covered with green spores. The greater efficacy was achieved in fruit with conventional treatment (89.0 %), followed by A1 with 72.9 %. The lowest infection index was for the A1 with 6 %, front C (10.5 %) and T (41.5 %). On the frame of an integrated managing management of postharvest diseases, the proposed treatment might turn out to be promissory to replace synthetic fungicides with protective against on P. digitatum.