Mycotoxins are toxic chemicals produced by specific fungi infecting crops; different fungal species produce mycotoxins of widely varying toxicity to humans and animals. Fusarium mycotoxins are produced while the wheat crop is growing and are extremely unlikely to increase after harvest under UK conditions.
In the field, infection of ears by some Fusarium species can result in mycotoxins when weather is warm and wet at flowering. Wet weather also delays harvest and increases mycotoxin risk. Wheat crops infected at flowering may have individual bleached spikelets or partially bleached ears, resulting in pink or chalky-white shriveled grains at harvest. However, there is little correlation between fusarium-damaged grain and mycotoxin occurrence.