Interactions between temperature and wheat head wetting duration on fusarium head blight intensity

ABSTRACT In experiments conducted in growth chambers with the susceptible wheat cultivar BR 23, interactions between five temperatures (10, 15, 20, 25 and 30°C) eleven wetting periods were assessed for fusarium head blight (FHB) intensity. Each temperature consisted of one experiment hours corresponded to treatments. The disease occurred even at 10ºC, minimum tested temperature, maximum incidence was 25oC, both after 50h wetting. Variations FHB intensity explained by Beta generalized model, spike duration Gompertz model. Disease modeled according wetness duration. resulting equation represents a description response spikelet combined effects Since infection requires long period, its origin may not be dew but rain, which suggests fungicide application before occurrence predicted rain during predisposition period.