ARS | Publication request: EVALUATION OF SPRAY COVERAGE AND CANOPY PENETRATION IN NURSERIES

Submitted to: International Society Arboriculture Annual Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 1998
Publication Date: N/A

Technical Abstract: Spray deposition, distribution and drift, produced by either an airblast or a high-clearance sprayer, were evaluated at production nurseries. Aqueous tracer solutions of either copper hydroxide or calcium nitrate were applied to Gleditsia triacanthos or Tsuga canadensis. Deposition was collected either onto honeylocust leaflets, hemlock needles or on inert microscope stub surfaces for direct electron beam analysis (EBA). Deposition was also collected on polyethylene tape for indirect conductivity analysis. A portable meteorological tower monitored ambient temperature, relative humidity, solar radiation, windspeed, and wind direction. EBA, combining scanning electron microscopy, energy dispersive x-ray microanalysis and digital image analysis, directly identified and quantified spray residue morphologically and chemically. Residue washed from polyethylene tape was analyzed with a conductivity system. Canopy penetration varied according to tree position, leaf surface (abaxial or adaxial), leaf height and position relative to the sprayer. Spray coverage was incomplete in either canopy. Both methods of tracer analysis were effective.