5. Conclusions

The survey found that 90% of the farmers in UCRB use pesticides on their fields. In total, 31 pesticide types were found in the survey area with Mancozeb and Profenofos as two most commonly used pesticides by the farmers, especially in chili and tomato fields. In terms of application frequency, highest frequencies were recorded for Abamectin, Mancozeb, and Profenofos in long bean, Difenoconazole and Mancozeb in cabbage, and Maneb in chili. These variations in pesticide application frequency influenced the yearly amount of the pesticides applied for each crop in the UCRB. The highest annual average amount of pesticide used per ha of pesticide-crop combination was Chlorothalonil on tomato, followed by Mancozeb on corn, and Chlorpyrifos on chili. Overall, the pesticide use estimation is relatively high with annual average of 24.6 kg/ha/year. Comparing prescribed and actual use on rice showed that most pesticides are used (per hectare or as diluted with water) more than the lowest recommended amount, and about a quarter is used more than the highest recommended amount. This comparison also indicated that some farmers use pesticides for rice that are not recommended for rice farming.
The presented data in this study is useful to estimate pesticide use for environmental risk assessment, especially because data on pesticide use in Indonesia and other low- and middle income countries are scarce. With these data a first scoping can be done on the potential impact of regional pesticide use for example to develop a monitoring programme of water quality targeting specific chemicals for analysis. Furthermore, an advanced research on motivations of pesticide use (types, under- or overuse) is recommended to improve estimates and facilitate sustainable pest management. It is also important to document pesticide usage on a national and regional level periodically as a means to more accurately evaluate associations between chemicals usage and human health or ecosystem disruption.