# Sheath Blight Disease Model

The model of R. solani ini rice fields is evaluating the risk for this disease on base of tempereture, leaf wetness and global radiation.

It checks last 120 hours:

- In case of consecutive leaf wetness it accumulate__ temperature depending values __for every minute.

- 12 °C to 15 °C it accumulates 1 per minute
- 16 °C to 17 °C it accumulates 2 per minute

18°C and more it accumulates 4 per minute

- At the end of the leaf wetness peirods it evaluates the accumulated values

- if the residual is greater than 2048 it increases the risk by 16 and subtractes 2048 from the value
- if the residual is greater than 1024 it increases the risk by 4 and subtracts 1024 form the value

- If global radiation is consecutive higher than 800 W/m² accumulate time in minutes and if radiation becomes lower evaluate values:

- Value > 512 = RiskValue - 32 Points , Value - 512
- Value > 256 = RiskValue - 8 Points , Value - 256
- Value >128= RisKValue - 2 Points, Value -128

The model results in a risk value between 0 and 100 indicating the times favourable for *R. solani *in rice fields.

The sheath blight model points out periods with a high risk for this disease. No sprays will have to be applied in periods where the risk is low. In periods with moderate risk spray interval can be prolongated and in periods with high risk spray interval may have to be reduced or more effective compounds will have to be used.