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

摘要

Seventeen experimental or registered combination treatment schedules were compared on three-tree sets of 13-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 2012, which allowed mildew inoculum pressure to stabilize on 2013 test trees. Products incorporated in the treatments included: Rally (FRAC 3), Topguard (FRAC 3), Indar (FRAC 3), Flint (FRAC 11), IKF-5411 (experimental, FRAC 7), Fontelis (FRAC 7), A15457 (experimental, FRAC 7) A19334 (experimental, FRAC 3 and 7), Inspire Super (FrAC 3 and 9), Pristine (FRAC 7 and 11), Merivon (FRAC 7 and 11), Luna Tranquility (FRAC 7 and 9), Manzate Pro-Stick (FRAC M3), Koverall (FRAC M3), Ziram (FRAC M3), Captan (FRAC M4), Silwet (adjuvant), LI-700 (adjuvant). Fungicide treatments were applied to both sides of trees on each indicated application date with a Swanson Model DA-400 airblast sprayer at 100 gal/A as follows: 11 Apr (TC, tight cluster); 23 Apr (B1, early bloom); 2 May (B2, late bloom); 8 May (PF, petal fall); 1st-7th covers (1C-7C) 18 May, 3 Jun, 19 Jun, 4 Jul, 19 Jul, 2 Aug, 15 Aug, 6 Sep (8C, York only). Maintenance applications applied to the entire test block with the same equipment included: Admire Pro, Assail, Altacor, BioCover MLT, Calypso, Delegate, FireWall, Imidan, Lannate LV, Provado, and Voliam Flexi. Inoculum placed over each Idared test tree included cedar galls, wild blackberry canes infected with the sooty blotchand flyspeck fungi, and bitter rot mummies 25 Apr. Other diseases developed from inoculum naturally present in the test area, including cedar-apple rust inoculum from red cedars in the vicinity. Foliar data are from counts of ten shoots per tree from each of four reps: 24 Jun (Idared), or 10 Jul (Golden Delicious) or eight shoots 22 Jul (York). Fruit data represent postharvest counts of 25 fruit per replicate tree sampled: 25 Sep (Idared), 26 Sep (Golden Delicious), or 3 Oct (York). Percentage data were converted by the square root arcsin transformation for statistical analysis.