Fungicide Application Timing Essential for the Management of Leaf Spot and Fruit Rot on Pomegranate (Punica granatum L.) in Florida.

Abstract

Pomegranate (Punica granatum L.) has emerged as an alternative fruit crop for growers dealing with devastating threats to citrus and avocado in the southeastern United States. However, foliar and fruit diseases are major constraints to commercial pomegranate production. Replicated field trials were performed in 2015 at three separate sites in Florida (Dover, Plant City, and Parrish) to evaluate Merivon (pyraclostrobin and fluxapyroxad), Luna Experience (fluopyram + tebuconazole), and a rotational program consisting of these two fungicides as well as Penncozeb 75DF (mancozeb) for the management of leaf spot and fruit rot of pomegranate. The fungicide programs were evaluated on the varieties Vietnam in Dover, FL; Angel Red in Plant City, FL; as well as Christina, Azadi, Vikusnyi, Alsirinnar, Sakerdze, and Wonderful in Parrish, FL. Mean leaf spot severity varied across sites at the end of each trial in August, with values ranging from 4.5 to 62.5% in Plant City, 7.5 to 45.8% in Dover, and 4.5 to 54.2% in Parrish. Based on area under the disease progress curve, all treatments that included at least one at bloom application significantly reduced disease levels compared with postbloom treatments and the nontreated control across all trial sites. Based on fruit rot incidence, Luna Experience and Merivon, when applied twice at bloom in the beginning of the season, reduced disease by 66.6 and 88.4%, respectively, in comparison with the nontreated control in Plant City. A rotational program further reduced disease by at least 97% at the end of the season in Parrish. The proper timing of fungicide application and rotation with different modes of action provided a feasible disease management option for pomegranate growers in the Southeast United States.