Towards crop adapted spraying (CAS) in berry crops

摘要

The concept of crop adapted spraying 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 8ndash;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.Testing the concept As a result of three years of intensive on farm research easyto-follow tables for crop adapted product use were devised for major berry crops. These tables state for four major consecutive growth stages the amount of the single strength spray volume the grower should apply with a properly calibrated sprayer. Most pesticides for legal use on berry crops in Switzerland have been tested and registered with a single strength concentration in a basic water volume of 1000 litres per hectare. The majority of growers apply spray broths of single strength.With stepwise increasing single strength spray broth volumes the tables provide an automatic increase of the amount of the product and active ingredient applied. The concept of CAS has been tested so far in a series of on farm experiments using properly calibrated and crop adjusted on farm spray equipment. DOI 10.1039/b104686c TOWARDS CROP ADAPTED SPRAYING (CAS) IN BERRY CROPS economical uses of pesticides Jacob Ruegg and Helena Bak of the Swiss Federal Research Station for Fruit Growing Viticulture and Horticulture at Wauml;denswil in Switzerland describe a simple spraying concept aimed at more efficient and Experimental results have shown that compared to farmersrsquo; traditional spray practices CAS allowed to save between 30 to 50 of the amount and costs of crop protection products with equal or better biological efficacy and usually lower residues on harvested berries.While farmers usually sprayed clearly beyond run-off spraying in our experiments was always carried out without or with minimum run-off. This journal is copy; The Royal Society of Chemistry 2001 Pesticide Outlook ndash; June 2001 Outlook For the forthcoming season 2001 we have organised four CAS-technology training courses for approximately 140 farmers in four distinct regions of German-speaking Switzerland. The implementation of CAS by selected key farmers will be followed up and evaluated. The emphasis will be on biological efficacy of the products sprayed savings in overall product use and residues on fruit at harvest time.Modifications to suit local conditions and preferences such as the application of reduced water volumes with multiple strength spray broths need to be tested and discussed with the industry. Implications of CAS for the registration of crop protection products in berry crops will be discussed within the registration authorities and with the industry as well. We believe that the CAStechnology has benefits to offer to the growers the environment and the end consumers. On farm evaluation of CAS in the next couple of years will reveal the practicality and viability of this crop tailored dosage and application of crop protection products in berry crops. Further work has been initiated to develop CAS also for selected vegetable crops such as tomatoes potatoes bushbeans and carrots. Figure 1. Total leaf and stem area and volume per ha of an Elsanta strawberry crop (Switzerland 2000) (6.7 plants per m2). The leaf area measured with an electronic leaf area meter was computed based on a sample of 5 harvested plants at each sampling date. The volume of the crop was computed based on crop height � crop width � length of crop rows. APPLICATIO