Evaluation of antibiotics and biological control products for control of fire blight, 2009.

摘要

The test was carried out in a mature ‘Rome Beauty’ and ‘Red Delicious’ apple orchard at the Penn State Fruit Research and Extension Center in Biglerville, PA. Trees received insecticide and fungicide applications, including dormant copper sprays,consistent with standard commercial practice for the northeastern U.S. Experimental treatments included three biological control products (Serenade ASO, Pantoea agglomerans products, or Regalia), two antibiotics (Mycoshield, or Kasumin), and a copper product (Kocide 3000). A streptomycin standard treatment and an untreated control were used for comparison. The P. agglomerans II treatment was applied on 28 Apr, 1 May, and 5 May; all other products were applied on 28 Apr and 1 May only. Treatments were applied dilute with a boom sprayer at 400 psi, which delivered 100 gal/A. The experimental design was a split-plot arrangement with treatments and cultivar as main-plot and sub-plot factors, respectively. Each treatment was replicated four times. Between 21 and 36 blossom clusters were tagged on each tree and inoculated on 29 Apr with a suspension of 1X10~8CFUs of Erwinia amylovora strain Ea 273. Trees were assessed for fire blight incidence (percent of diseased clusters) and disease severity (using the following scale: 0=no infection; 1=1-25%; 2=26-50%, 3=51-75; 4=76-100% cluster infection) on May 18 and May 27. Data were analyzed with analysis of variance and means separated using Fisher’s protected LSD test (alpha = 0.05).