Collection and evaluation of relevant information on crop interception

Abstract

This project was performed at Aarhus University from November 2011 to May 2013, and the aim was to collect scientific information on crop interception of plant protection products and submit proposals for revision of the existing FOCUS values. The present FOCUS values on crop interception were published by the FOCUS ground water group (FOCUS, 2000; Anonymous, 2011b) and in the FOCUS surface scenarios (Anonymous, 2011a). Limited experimental data were available to the working group at that time, and therefore many of the existing FOCUS values were obtained using indirect data such as crop coverage or by interpolation or extrapolation of data. On the request of EFSA a scientific report on cereals was prepared by van Beinum and Beulke (2010) from The Food and Environment Research Agency (FERA). Besides a collection of literature on cereals, they made a literature database, where references on other crops were collected as well. Thus, the aim of the work reported here was to compile and evaluate references on all other FOCUS crops than cereals. The literature database was updated with published studies after 2010 by searching in 13 databases. FERA reduced the search to literature published after 1980, but for other crop than cereals the number of papers was limited and it was decided to include also papers published before 1980. In addition, a number of papers were collected by personal contact to people from the network of Aarhus University, Department of Agroecology. Searches were performed using 7 main search terms. After the search, all references were evaluated in accordance with a set of minimal and exclusion criteria developed by van Beinum and Beulke (2010). The exclusion criterion “non-European” was not used in the study by van Beinum and Beulke (2010); therefore papers rejected as “non-European” were re-evaluated. In total 51, articles were accepted with studies on one or more of the crops mentioned by FOCUS (appendix A). The largest number of studies was found for apples. For eight of the FOCUS crops no studies fulfilling the criteria could be found. In this report, literature regarding vine, pome fruit, potato, citrus, cotton and sugar beet was evaluated, and the crop interception values reported were employed for revision of the existing FOCUS values (appendix E). For a number of crops (alfalfa, peach, maize, olive, pea, strawberry, tomato, bean and soybean) the data regarding growth stage and crop interception were limited, so data were stated in the report but not used for revision. No studies were found on bush berries, but due to the extrapolation rules it was revised in accordance to data derived from vine. All relevant data from the articles, such as spray equipment, sampling, growth stages etc., were compiled in an Excel file (Annex 2). In the report from FERA, six methods (M1, M2, M3, M4, M5 and M6) were suggested for calculation of interception factors for which measurements were based on deposition on soil or plants. In vine, it is also common to measure the amount of drift and spray that is collected from recycling, when equipment such as tunnel sprayers are employed. Therefore, three further calculation methods were found on bush berries, but due to the extrapolation rules it was revised in accordance to data derived from vine. All relevant data from the articles, such as spray equipment, sampling, growth stages etc., were compiled in an Excel file (Annex 2). In the report from FERA, six methods (M1, M2, M3, M4, M5 and M6) were suggested for calculation of interception factors for which measurements were based on deposition on soil or plants. In vine, it is also common to measure the amount of drift and spray that is collected from recycling, when equipment such as tunnel sprayers are employed. Therefore, three further calculation methods were proposed, M7, M8 and M9. To evaluate the interception values obtained from literature with the values earlier suggested by FOCUS (2000), data were plotted against the growth stage of the crop. For sugar beet, stone fruit and cotton, the FOCUS values seem to be in accordance with the crop interception values derived from most of the experiments reported in the articles. In potato and citrus, the average of crop interceptions values derived from the experimental data was above the FOCUS values, and increasing the values is suggested. In vine and bush berries a decrease of the crop interception (CI) value was suggested. Apples were more difficult to evaluate due to a very large variation between the reported measurements. Evaluation of the average of all data and of the average of data collected on apples that are similar to common modern apple orchards; it is recommended to decrease the CI values by 5% at flowering stage and by 15% at full foliage. Thus, in the present report the proposal for new CI FOCUS values were given for vine, apple/stonefruit, citrus, bush berries and potato. Calculations can be found in sheet 5.1. – 5.7. calculations, in annex 2.