This paper describes a web-based information system for plant disease forecast that was developed for crop growers in Gyeonggi-do, Korea. The system generates hourly or daily warnings at the spatial resolution of 240 m×240 m based on weather data. The system consists of four components including weather data acquisition system, job process system, data storage system, and web service system. The spatial resolution of disease forecast is high enough to estimate daily or hourly infection risks of individual farms, so that farmers can use the forecast information practically in determining if and when fungicides are to be sprayed to control diseases. Currently, forecasting models for blast, sheath blight, and grain rot of rice, and scab and rust of pear are available for the system. As for the spatial interpolation of weather data, the interpolated temperature and relative humidity showed high accuracy as compared with the observed data at the same locations. However, the spatial interpolation of rainfall and leaf wetness events needs to be improved. For rice blast forecasting, 44.5% of infection warnings based on the observed weather data were correctly estimated when the disease forecast was made based on the interpolated weather data. The low accuracy in disease forecast based on the interpolated weather data was mainly due to the failure in estimating leaf wetness events.

BACKGROUND: About 81% of nitrous oxide (N 2 O) emissions from agricultural land to the atmosphere is due to nitrogen (N) fertilizer application. Mitigation of N 2 O emissions can be more effective in controlling biochemical processes such as nitrification and denitrification in the soil rather than decreasing fertilizer application. The use of urease inhibitors is an effective way to improve N fertilizer efficiency and reduce N 2 O emissions. Several compounds act as urease inhibitors, but N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide. METHODS AND RESULTS: Hot pepper and chinese cabbage were cultivated in five treatments: standard fertilizer of nitrogen-phosphorus-potassium

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This study was conducted to determine the economic injury levels and control thresholds for the striped cabbage flea beetle, Phyllotreta striolata (Coleoptera: Chrysomelidae), on Chinese cabbage at two different planting times. The number of inoculated adults per 10 cabbages was 0, 2, 4, 8, and 16 at the early developmental stage of the cabbage5 days after planting) and 0, 10, 20, 30, and 40 at the middle developmental stage (30 days after planting). Damages to the leaves at the first inoculation were 2.5-21.1% and at the second inoculation were 1.8-26.3% after harvesting. The linear relationships between population density and yield reduction were as follows: Y = 1.3475X + 2.135 (R 2 = 0.8699) at the early developmental stage and Y = 0.703X -1.78 (R 2 = 0.966) at the middle developmental stage. On the basis of these results, the economic injury levels caused 5% loss of yield; there were 2.1 adults per 10 Chinese cabbage at the early developmental stage and 9.6 adults per 10 Chinese cabbage at the middle developmental stage.