Reflection of agricultural sprays from leaf surfaces

Abstract

The bounce of spray drops delivered from a hydraulic nozzle to cabbage leaves was investigated. A glass chamber containing cabbage leaf samples angled at 45° was sprayed using a track sprayer. Spray drops bouncing from the leaf surface were caught on water‐sensitive cards and their in‐flight diameters determined. Bounce was associated with solutions of high dynamic surface tension and drops of large size. At 40psi with a nozzle to target distance of 40cm, large drops of insecticide solutions (>250μm) shattered to form a large number of small drops. The spray adjuvant, Windfall, was found to eliminate bounce under test conditions. Implications of the results for pesticide application efficiency are discussed.

Key words:

• pesticides
• sprays
• retention
• reflection