Evaluation of fungicide programs for control of apple scab, cedar apple rust, and summer diseases on 'Rome Beauty' apples in Pennsylvania, 2014

摘要

Fungicide programs were evaluated to control early season diseases: apple scab (Venturia inaequalis) and cedar apple rust (Gymnosporangium juniperi-virginianae), as well as summer diseases: sooty blotch (disease complex) and flyspeck (Zygophiala jamaicensis). The efficacy trials were conducted in a 5 year old orchard block at the Penn State Fruit Research and Extension Center, which is arranged as single tree plots planted with the cultivar 'Rome Beauty' on M.111 rootstock. Treatments were arranged in a randomized complete block with 4 replications. Treatments were applied using a backpack sprayer until runoff. Treatment applications were made on 8 - 15 day intervals for early diseases; 10 -14 day intervals for summer diseases starting at half- inchgreen tip on 18 Apr through eighth cover on 26 Aug. A standard insecticide maintenance program was applied to the entire orchard with an airblast or boom sprayer delivering 100 gal/A at 400 psi. Weather data was recorded with a Decagon weather monitoring system, and apple scab and cedar apple rust infection periods were reported. The Modified Mills Table was used for apple scab; a model adapted from the APS Compendium of Apple and Pear Diseases and Insects for cedar apple rust. Rainfall totals for April, May, June, July, and August were 5.93, 5.48, 5.0, 2.14, and 5.55 inches, respectively. For each treatment, incidence of apple scab and cedar apple rust was determined by randomly selecting 10 shoots per tree per replication and evaluating all of the leaves on each shoot for disease on 23 Jul. Fruit were harvested 2 Oct and evaluated by assessing 25 apples per treatment/tree (100 fruit total evaluated/treatment) for disease incidence of apple scab, cedar apple rust, sooty blotch, and flyspeck. Mean percent incidence was calculated, and data were analyzed using analysis of variance and the Fisher's Protected LSD Test determined the mean separation.