Tree-row-volume-based sprays of copper bactericide for control of citrus canker

摘要

Commonly, pre-determined copper spray volumes are indiscriminately applied to citrus orchards of different ages and sizes for control of citrus canker (Xanthomonas citri subsp. citri) leading to a waste of resources, such as water, energy, and chemicals. This study evaluated the effectiveness of copper applied following the tree-row-volume (TRV) methodology for control of citrus canker on sweet orange trees. Treatment design was based on the theoretical runoff volumes previously determined for the exterior and interior of a citrus tree. The volumes 150 (standard), 100 (internal runoff point), 70 (intermediate) and 40 mL (external runoff point) of spray mixture/m(3) of tree canopy were tested at the standard copper rate of 0.525 g metallic copper/L. Additionally, 70 and 40 mL/m(3) were also tested with copper rate correction by leveling up the theoretical deposition of copper bactericide to that obtained with 100 mL/m(3).