Spraying

spraying, a vineyard practice of applying liquids and powders to control pests, diseases, and weeds. Late last century, vineyard sprayers were often drawn by draught animals and operated with manual pumps; nowadays they are usually mounted on tractors or drawn by them, and sometimes mounted on mechanical harvesters in order to spray several rows at once.

The aim of economically and environmentally sound spraying is to achieve maximum coverage of the ‘target’ (leaves, bunches, or weeds) by applying minimum amounts of the appropriate agrochemical (or other products). There should be ideally no spray material lost to the surrounding environment as ‘spray drift’. Good coverage depends on having very small droplets, although these are more readily blown off target by wind than large drops. A welcome development is the so-called tunnel sprayer, which prevents spray escaping into the environment. The vine canopy beside the tractor is enclosed by a cover or tunnel, usually made of fibreglass, with the spray jets mounted inside the tunnel. Any spray droplets not caught by the vine are caught by the opposite side of the tunnel and can therefore be retrieved and returned to the spray cart. Such units save a lot of spray material, especially early in the growing season when the ‘target’ is small.