Fire blight blossom blight suppression on Idared apple, 2009.

摘要

Two experimental materials and two rates of a copper product (C-O-C-S) were compared to streptomycin (Firewall) for blossom blight control and fruit finish effects. The test was established in four randomized blocks on 27-yr-old trees, using single-tree replications with border rows between treatment rows. All treatments were applied to both sides of the tree with a Swanson Model DA-400 airblast sprayer at 100 gal/A on the morning of 17 Apr (most clusters with king bloom open), and repeated on 24 Apr(full bloom) and 28 Apr (all petals off). The test strategy was to inoculate after the first two applications, but to make a third application without a follow-up inoculation. Four selected branches per tree, each with 25 to 40 blossom clusters, were inoculated by spraying to drip with a bacterial suspension containing 1X10~6CFU/ml Erwinia amylovora in the evening of the first two treatment days (17 Apr and 24 Apr). Infection data were based on counts of number of blossom clusters present at the firstinoculation. A cluster was rated as infected if it had at least one blossom with fire blight symptoms on 30 Apr or one cluster leaf with symptoms on 11 May. Maintenance materials, applied to the entire block with a commercial airblast sprayer, included Rally, Dithane, Asana + oil, Calypso, and Imidan.