Published online by Cambridge University Press: 04 July 2016
Aerial crop spraying necessitates the lowest feasible application rates to minimise costs. The low volumes now being used in the Tropics and in this country often require very high concentrations of active ingredient. Most agricultural sprays are formulated for use in 10-100 gallons per acre. When the same weight of chemical is applied in one gallon or less per acre any one of hitherto disregarded factors, such as surface tension, rate of evaporation, density, viscosity, dynamic catch, and so on, may unexpectedly reach a critical value. An understanding of the limits of these factors is essential for the diagnosis or prevention of faulty biological performance.