It starts after infection of cobs with F. graminearum through silk channel. I presume that level of DON do not increase after silage corn harvest and silage production. In this stage other toxins like ochratoxins may be produced.
Hi: The amount of DON production by the isolated depends on the fungal strain and environmental conditions, the production of toxin started when the infection is starting.
If production depends of environment and the kind of stain, are we able to know which stains are the more productive of DON according to the environment ?