Fungicide efficacy in peach rusty spot control in Serbia

Abstract

Rusty Spot has long been known as a harmful peach disease in many parts of the world. During the past several years, rusty spot infection of the late-maturing peach cultivars (Summerset, Suncrest, Fayette and O?Henry) caused significant yield losses in Serbia. Although the etiology of the disease is still unknown, there are numerous studies attempting to set a strategy for its control and recommend appropriate chemical and other peach protection methods. However, because of specific environmental conditions in Serbia, recommended protection method using repeated fungicide treatments, starting from petal fall, did not prove to be efficient and the rate of infection in some susceptible peach cultivars reached 100%. In 2003 and 2004 a field trial was conducted in order to test the efficacy of fungicides (a.i. kresoxim-methyl, flusilazole and sulfur) for the efficient control of Rusty Spot epidemics. The trial was carried out under conditions of natural infection on the peach cv. Summerset at the locality of Bela Crkva, Serbia. In the untreated control plots, high disease incidence was recorded with the percentage of affected fruit surface ranging from 33.5% in the first, up to the 35.4% in the second year of the trail. Among fungicides included in the trial, kresoxim-methyl proved to be the most efficient (90.25% in the first and 91.12% in the second year of the trial), flusilazole exhibited lower efficacy (87.28% and 80.61%, respectively) while sulfur was the least efficient (82.33% and 80.30%, respectively). Determination of the most efficient fungicide for the peach rusty spot control in Serbia provides basic information for further investigations which will include optimization of treatment terms, as well as additional agro-technical control measures.