Evaluation of summer disease programs on Rome Beauty apple in PA, 2012

摘要

The objective of the trial was to evaluate the cumulative effect of early season and summer fungicide programs for control of summer diseases and apple scab on mature Rome Beauty apple trees located at the Penn State Fruit Research & Extension Centerresearch orchard. Treatments were arranged in a randomized complete block design with four replications per treatment. Treatments were applied dilute to both sides of the trees with a boom sprayer at 400 psi, which delivered 100 gal/A. Fungicide programsfor early season diseases were applied from half in. green tip up (22 Mar) to petal fall (27 Apr). Summer treatment applications were made at 14 to 30 day intervals from 12 May (1st cover) to 8 Aug (7 cover). A program for insect management was appliedseparately to all the treatments with an airblast sprayer at 100 gal/A at 400 psi. Weather data was recorded with electronic monitoring systems (Davis ProVantage Weather System). Rainfall for Apr, May, Jun, Jul, and Aug was 2.4 in., 5.41 in., 3.21 in., 5.11 in., and 3.86 in., respectively. Disease incidence was determined on 25 randomly selected Rome Beauty fruit on 15 Aug. Disease severity was rated on a 0 to 7 scale, based on an estimate of the percentage area of tissue covered by symptoms, where 0=0%; 1=1-3%; 2=3-6%; 3=6-12%; 4=12-25%; 5=25-50%; 6=50-75%; 7=more than 75%. For analysis, ratings from each fruit were converted to a percentage, where 0=0%; 1=2%; 2=4.5%; 3=9%; 4=18.5%; 5=37.5%; 6=62.5%; 7=87.5%. Data was analyzed by analysis of varianceand significance between means was determined using Fisher’s Protected LSD test (P < 0.05) (SAS Institute Inc., Cary, NC).