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.

Rđasta mrežavost plodova breskve odavno je poznato i ekonomski značajno oboljenje u mnogim delovima sveta. U Srbiji tokom proteklih godina ovo oboljenje nanosi značajne štete na poznim sortama breskve (Summerset, Suncrest, Fayette i O'Henry). Mada etiologija bolesti nije poznata, brojna istraživanja u mnogim delovima sveta pokušavaju da uspostave strategiju za kontrolu i preporuče odgovarajuće hemijske i druge metode zaštite breskve. U agroekološkim uslovima Srbije strategija primenjena u svetu, da suzbijanje prouzrokovača rđaste mrežavosti treba sprovoditi u višekratnim tretmanima od fenofaze precvetavanja, nije dala zadovoljavajuće rezultate. U pojedinim godinama zaraza plodova osetljivih sorti breskve dostiže 100%. U periodu od 2003. do 2004. godine, ispitivana je efikasnost tri fungicida (kresoksim-metil, fluzilazol i elementarni sumpor) u cilju iznalaženja mogućnosti uspešnije zaštite breskve od prouzrokovača rđaste mrežavosti plodova. Ogled je izveden na breskvi, sorte Summerset, u uslovima prirodne zaraze na lokalitetu Bela Crkva. Intenzitet zaraze rđaste mrežavosti plodova na osnovu procenta zahvaćene površine plodova, u kontrolnim parcelama kretao se od 33,5% u prvoj do 35,4% u drugoj godini ispitivanja. Tokom obe godine ispitivanja kresoksim-metil ispoljio je najveću efikasnost (90,25% u prvoj, odnosno 91,12% u drugoj godini ispitivanja), nižu fluzilazol (87,28%, odnosno 87,61%) i najnižu elementarni sumpor (82,33%, odnosno 80,30%). Određivanje fungicida sa najefikasnijim delovanjem prema prouzrokovaču rđaste mrežavosti plodova breskve u Srbiji predstavlja preduslov za dalja ispitivanja koja će uključiti pre svega optimizaciju rokova fungicidnih tretmana kao i određivanje drugih agrotehničkih mera kontrole.