Agricultural Pesticide Use in the Upper Citarum River Basin, West Java, Indonesia

1. IntroductionPesticides are used in order to protect valuable assets such as crops and human health against potential adverse impacts from pest, insects, weeds, and pathogens. As such, pesticide use is a major foundation of the agricultural intensification observed since the middle of the 20th century (Masia et al., 2014; Silva et al., 2019). The global amount of pesticides used has been estimated at approximately 6 billion pounds in 2011 and 2012 (USEPA, 2017). This amount keeps increasing, particularly in low and middle income countries (Akter et al., 2018; Balmer et al., 2019; Phillips McDouglas Agribusiness Intelligence, 2019). The extensive and improper use of pesticides can also have negative impacts, e.g. on the crop itself, on human health and on ecosystems, especially in aquatic environments (Verger and Boobis, 2013; Tsaboula et al., 2016; Kapsi et al., 2019). In order to prevent such negative impacts, the marketing and use of pesticides are strictly regulated in most countries.Appropriate management of pesticides requires information on the types and amounts of pesticides used. Eurostat (2008) advocates collection of usage statistics in particular for: (1) provision of annual usage estimates in countries; (2) monitoring changes over time (Coupe and Capel, 2016); (3) environmental protection; (4)  consumer protection: providing information for residue monitoring; (5) operator protection (improving or optimizing use); (6) monitoring the potential movement of pesticides into water; (7) policy advise during review programs (reviewing use of existing pesticides); (8) providing information for approval of new pesticides. However, the public availability of pesticide use data is generally scarce, i.e. because of proprietary data issues, poor registration, lacking regulations or the costs involved. Eurostat (2008) stipulates that the cost benefits for gathering actual usage statistics far outstrip the investments. An excellent example of collecting usage data is the Pesticide Use Reporting Program in California in which farmers are required to monthly report pesticide use (California Department of Pesticide Regulation, 2000).Pesticide use data can take the form of sales data and usage data. Sales data are more generic and cannot be related directly to the actual use in time and space since they do not provide details on crop, timing, spatial variation and the dose applied (Eurostat, 2008). These details are needed in order to estimate pesticide emissions, model surface water contamination, estimate risks, set priorities and identify mitigation measures (Herrero-Hernandez et al., 2017; Bidleman et al., 2002; Konstantinou et al., 2006; Al-Khazrajy & Boxall, 2016; Van Gils et al., 2019). Usage data do provide the kind of detail needed to satisfy this kind of governance, research and management needs. Unfortunately, usage data is typically unavailable or difficult to obtain for all crops produced in an area, particularly in low and middle income countries like Indonesia (Mariyono et al., 2018).The aim of the present study was to determine the pesticide use by farmers in the Upper Citarum River Basin (UCRB) and make the data open access. The study was initiated to obtain input data required for predicting surface water concentrations of pesticides in the UCRB. In order to acquire the data, a survey among 174 farmers was conducted, focusing on the types and amounts of pesticides used on major crop types.