Preharvest fungicide programs for control of postharvest brown rot Rhizopus rot and Gilbertella rot in peach 2013

摘要

Control of postharvest fruit decay with preharvest sprays was tested on 18-yr-old peach trees at the Musser Fruit Research Farm, Seneca, SC. The block received the following maintenance sprays (rate/acre): Chloronil 720 (2 qt) on 19 Mar; Initiate 720(2 qt) on 28 Mar; Imidan 70WSB (2 lb) + Captan 80WDG (3 lb) on 15 Apr, 9 May; Asana 0.66 EC (14 oz) + Captan 80WDG (3 lb) 29 Apr; Imidan 70WSB (2 lb) 20 May, 28 May; Avaunt 30SG (6 oz), 3 Jun; Mustang Max (4 oz) 11 Jun, Assail 30SG (7 oz) on 20 Jun. Morethan 0.1 in. of rainfall occurred on 02, 05, 11, 12, 18, 23, 24 Mar, 04, 12, 17, 19, 27, 28 Apr, 04, 05, 07, 11, 18, 19, 22, 23 May, and 02, 05, 06, 07, 09, 10, 11, 13, 17, 18, 26, 27 Jun in the form of 0.19, 0.48, 0.75, 0.13, 0.91, 0.34, 1.35, 0.74, 0.52, 0.73, 0.3, 0.8, 0.19, 1.75, 0.84, 1.44, 0.16, 0.11, 0.77, 0.12, 1.15, 0.12, 1.76, 1.94, 1.49, 0.61, 0.49, 0.25, 0.15, 0.45, 0.39, 0.15, 0.23, 0.36 in. of precipitation, respectively. Treatments were replicated four times in a randomized complete block design, one tree per replicate. Trees were sprayed to runoff (4.5 gal/tree) at 250 psi with a handgun sprayer on 14 Jun and 21 Jun. When fruit were at commercial shipping maturity (28 Jun), 50 asymptomatic fruit of shipping maturity stage (no green color but still firm) were arbitrarily picked from each tree and stored for 7 days. Fruit were placed in two 25-pocket plastic trays in cardboard boxes and stored in an air-conditioned room at 70-72oF. Decay was calculated as a percentage 3 and 7 days postharvest (dph).