Efficacy of chemical products for control of brown rot and rust of peach in north Georgia, 2008

摘要

Fungicides were evaluated for control of brown rot in an experimental block of a late-ripening peach variety (O’Henry) located at the University of Georgia Horticulture Farm (Watkinsville, GA). In addition, peach rust control was also evaluated. Chemicals were applied with an airblast sprayer (60 gal/A spray volume) on 17 and 24 Jul (pre-harvest sprays). Treatments included an untreated control, Pristine (boscalid + pyraclostrobin) as the chemical standard, Inspire (difenoconazole), Inspire + Orbit(propiconazole), Inspire Super (difenoconazole + cyprodinil), Quadris Top (difenoconazole+ azoxystrobin), and A15909 (propiconazole + azoxystrobin). Five replications of each treatment were applied to a randomized complete block design, with each plot consisting of four trees; the outer two trees in each plot were not utilizedfor ratings. Unsprayed rows were left between each spray row. All cultural practices were in keeping with peach production methods commonly observed throughout the Southeast. Earlier in the season, maintenance sprays for scab (BravoWeatherStik 6F at 4 pt/A at shuck split and Yellow Jacket Sulfur 90WP at 9 lb/A through all cover sprays) were applied to all treatments, including the untreated control. At full maturity, 39 asymptomatic fruit were harvested from each plot for rotassessments (31 Jul). The fruit were placed on plastic produce trays and stored at ambient room temperatures (air-conditioned room; ~77 F). Rot incidence was recorded at four, seven, and ten days after harvest. Defoliation from peach rust wasrecorded on 10 Nov. Bacterial spot was not present in this trial, due to maintenance sprays for bacterial spot and limited rainfall during critical infection periods, so all defoliation was attributed to rust.