Efficacy of fungicides for management of blueberry rust, Ware County, Georgia, 2016

摘要

Fungicides were evaluated for control of blueberry rust in a replicated trial within a single row of mature (10-yr-old) highbush blueberries (cv. Rebel) in a commercial field near Manor, GA. Of particular interest were the relative levels of control among the four demethylation inhibitor (DMI) fungicides and one premix containing a DMI fungicide. Treatments were assigned using a randomized complete block design with five single-bush replicates per treatment; adjacent buffer rows and a single bush oneither side of treatments were left unsprayed to prevent spray drift. Treatments were applied until run-off with approximately 0.5 gal applied per five bushes (equivalent to 100 gal/A) using a CO2 backpack sprayer fitted with a cone nozzle at 40 psi. Treatments included an untreated control, Abound (azoxystrobin), Pristine (pyraclostrobin + boscalid), Indar (fenbuconazole), Orbit (propiconazole), Proline (prothioconazole), Quash (metconazole), Aprovia (benzovindiflupyr), Quilt Xcel (azoxystrobin + propiconazole), and a split schedule application of Abound (azoxystrobin) until harvest followed by Bravo (chlorothalonil) until trial termination. Application dates were 6 Apr, 21 Apr, 4 May (last spray prior to harvest), 18 May, 1 Jun, 15 Jun, and 29 Jun. On each of five assessment dates (30 Mar, 21 Apr, 2 Jun, 15 Jun, 7 Jul), 50 leaves per bush were destructively sampled and assessed for blueberry rust with severity calculated as % affected leaf area and incidence as the proportion of infected leaves. Thearea under the disease progress curve (AUDPC) was.