Purple Spot Infection Model
The Stemphylium versicarium infection model is based on the work of SUHERI and PRICE in onions and LLorent, VILARDELL, BUGIANI, GHERARDI and MONTESINO in pear.
Infection curves for light, moderate and severe infections are computed.
With this separation into favourable, moderate favourable and very favourable situations it is to the grower to decide how big the disease pressure in a specific field will be and if he has to cover a specific infection.
Leaf wetness > 0 (start for infection) or rel. humidtiy > 90% (just if there was already an infection before calculated and is still holding)
light infection (11-30°C), moderate infection (13-30°C), severe infection (16-30°C), array with leaf wetness duration (see above)
Reset: if rel. humiditiy is lower than 70%.