Spraying techniques for orchards of standard trees

Abstract

A comparison was made between conventional high-volume spray application by automatic air-carrier sprayer and (i) half the volume of spray at the same concentration but with improved wetting properties and (ii) the same active chemical applied at 25 × normal concentration. The work was done in an orchard of large dense trees to see if either of the new techniques offered a more economical method of spraying old orchards of culinary varieties by saving respectively chemical or application time. Measurements of spray deposition and insect, mite and fungus control indicated that all treatments gave poor results high in the trees. The treatment employing a reduced amount of chemical had serious failings. Scab control was good using lime sulphur in high concentration, and application time was reduced to one third, but mite control by ovicide was inadequate.