Effect of Spring-pruning Method, Copper Sprays, and Training Systems on Bacterial Canker of Sweet Cherry
Project Leaders: J. Carroll, NYS IPM; T. Robinson, Dept. of Horticultural Sciences, Cornell University; T. Burr, Dept of Plant Pathology and Plant Microbe-Biology, Cornell University; S. Hoying, Dept. of Horticultural Sciences, Cornell University.
Abstract: Pruning techniques and bactericides were evaluated for managing bacterial canker in sweet cherry. The impact of pruning date on infection was investigated in replicate orchard blocks, three at the NYS Agricultural Experiment Station, Geneva NY and two at the Hudson Valley Laboratory, Highland, NY. Trees were pruned March 25 and 15, April 24 and 15,May 22 and 14, and July 28 and 31, in Geneva and Highland, respectively. In Highland no bactericides were applied to the trees. In Geneva, the replicate blocks were treated with either no bactericide, copper (COCS or Cuprofix Ultra at4 lb/100 gal), or phosphorous acid (Agri-Fos at 2.5 qt/100gal) on March 26,April 24 and April 25. In Geneva, an additional 21 trees in each block were pruned on April 24 to more thoroughly investigate the effect of the bactericide treatments before and after the April 24 pruning. Pruned branches averaged 3.5cm in diameter and all cuts were made to leave a stub approximately 20-cm-long.Pruned cut surfaces were inoculated with copper-sensitive Psuedomonas syringaep v. syringae (Pss) (10 to the 8th cfu/ml) immediately after pruning. Bacterial canker symptom development was assessed on stubs five times during the growing season, once in June prior to the July pruning date and subsequently at two week intervals from August to October.