Disease control by experimental and registered fungicides and mixtures on Golden Delicious, Idared, and York Imperial apples, 2014

摘要

Fourteen experimental or registered combination treatment schedules were compared on three-tree sets of 14-yr-old trees. The test was conducted in a randomized block design with four replicates separated by non-treated border rows. Test rows had beennon-treated border rows in 2013, which allowed mildew inoculum pressure to stabilize on 2014 test trees. Fungicide treatments were applied to both sides of the tree on each indicated application date with a Swanson Model DA-400 airblast sprayer at 100 gal/A as follows: 13 Apr (all treatments, TC, tight cluster, Golden Delicious; York !4 "-green; Idared TC-open cluster); 24 Apr (Bl, early bloom, all except #7); 28 Apr (Trt 7 only); 4 May (all except #7; PF, petal fall); 9 May (Trt 7 only); 18 May (1C, 1st cover; all except #7); 23 May (Trt 7 only); 31 May (2C, 2nd cover; all except #7); 7 Jun (Trt 7 only); 14 Jun (3C, 3rd cover; all except #7); 20 Jun (Trt 7 only); 4C-8C, 4th-8th covers, all treatments: 28 Jun, 12 Jul, 25 Jul, 11 Aug, 29 Aug. Inoculum placed over each Golden Delicious test tree included cedar galls, wild blackberry canes with the sooty blotch and flyspeck fungi, and bitter rot mummies 20 May. Other diseases developed from inoculum naturally present in the test area, including cedar-apple rust inoculum from red cedars in the vicinity. Maintenance sprays, applied to the entire test block included Admire Pro, Altacor 35WG, Assail 30SG, Asana XL, BioCover MLT, Calypso 4F, Delegate 25WG, Diazinon 50W, Imidan 70WSB, Lannate LV, and Provado1.6F.. Ethephon 3 pt + Carbaryl 3 pt/A were applied to Golden Delicious trees as a thinning application 23 May. Foliar data are from counts of ten shoots per replicate tree: 18 Jun (York), 16 Jul (Idared), and 25 Jul (Golden Delicious). Fruit data represent postharvest counts of 25 fruit per replicate tree sampled: 17 Sep (Idared), 30 Sep (Golden Delicious) or 6 Oct (York). Idared fruit were held in cold storage 33 days, and Golden Delicious 17 days prior to start of warm temperature incubation; York fruit were incubated at warm temperatures immediately after harvest. Percentage data were converted by the square root arcsin transformation for statistical analysis with SAS.