Towards crop adapted spraying (CAS) in berry crops

Abstract

For an efficient use of pesticides, targeted against diseases and pests which attack green plant parts and fruit, a certain amount of active ingredient must be deposited per unit leaf area of the target plant. Measurements in commercial berry crops in various parts of Switzerland over the last 3 years have shown that the leaf area of strawberries, raspberries, blackberries and red currants increase by a factor of 8-12 from the early stages of growth till fruit maturing (Figure 1). This marked increase in leaf area implies that the dosage of the products would need to follow, for practical reasons, a stepwise increase approximately matching the increase of the leaf area. This concept of adapting the product dosage to the growing leaf area of a given crop coupled to the application of the product with a well-calibrated sprayer properly adjusted to reach all parts of the leaf canopy of the specific crop can be termed Crop Adapted Spraying (CAS). Commonly labels on crop protection products only state a certain amount of product in kilograms or litres to be used per hectare. It is left to the grower whether and how to adapt the dosage of the product to the growing crop. Onfarm observations have shown clearly that most growers are uncertain about what amount of product in which volume of water they should use at a given growth stage. Often products are grossly under-or overdosed, and spray equipment is not or is poorly calibrated and adjusted to the specific crop. Thus our primary goal for developing CAS in berry crops was to provide growers with a guideline on how to use fungicides, insecticides and acaricides more efficiently and economically.

A generic method of pesticide dose expression: Application to broadcast spraying of apple trees

“…However, the standard method of pesticide dose expression does not take this effect into account. The concept of 'Crop Adapted Spraying', to account for some combined effects of crop structure and sprayer configuration, has been put forward to remedy some of the inadequacies of the standard method of pesticide dose expression (Ruegg & Bak, 2001). This is not a new concept or a new avenue of research.…”