Fusarium Mycotoxin Alert
Infection trials with extended leaf wetness periods of Fusarium head blight lead to high contents in mycotoxin. From this information an leaf wetness period of 48 hour or more during stage 61 and 69 is assumed to give a high risk of mycotoxins. Experiences made troughout the analyces of DON in commercial grown wheat showed that leaf wetness periods long enough for infection following an initial infection in stage 61 to 69 can increase the DON values too. In case of longer leaf wetness periods mycotoxins can increase up to stage 85. Field.climate accumulates a risk figure proportional to the infection progress for every succesful infection periods over the period which has been selected to be propriate for this calculations. 6 just completed infection periods would lead to a risk of 100%. Normally the leaf wetness period leading to a fusarium infection is longer than in miniumum needed. Therefore most fusarium infections will lead to an risk increase of more than 17%. The risk value pointing to a problematic mycotoxin situation is depending on the field history. Wheat grown after non tillage corn or non tillage wheat after non tillage corn can only carry a small risk if it is not sprayed at the optimum situation. In unsprayed wheat we have to expect increased DON values already after 35% of risk. Wheat after non tillage wheat following any other crop than corn or wheat can carry a higher risk of 50%. If we have wheat after corn or wheat with tillage the risk being accsted can be extended to 70%. First year wheat shoulld be tested for DON if the risk exceeds 100%.