Examination on the efficacy of spraying operations in vine plantations

Abstract

Our investigation was to conduct the measurement of spray losses and efficacy using an air-carrier sprayer in
situ, that is during the practical work to get reliable scientific data to the common practice in vine plantation.
During the end of April to mid August six measurements were taken depending on the developmental stage
of vine stocks. To determine the degree of chemical deposition and spray losses, leaf samples were taken, or
rough-surface plastic sheets and petri-dishes were used. As a tracer Pyranin-solution were used the deposited
active substance of samples were determined in a laboratory using a fluorometer. To measure the chemical’s
deposition on the upper and lower surfaces of the leaves, water-sensitive test papers were placed onto
assigned leaves at each levels. They were evaluated using a computerized image analysis. The evaluation of
relations between developmental stage and efficacy of sprayings showed, that the amount of liquid sprayed
onto the target surface (that is the foliage) as well as the value of recovery, will mainly be determined by the
LAI, which shows the development of the foliage. The recovery values of 55-60 % is considered in the
literature as a basis for comparisons, and is in case of traditional axial fan sprayers only acceptable and true,
if the foliage is very well developed.