Growth of Aspergillus on crops is common when drought conditions predominate. This is possibly because lack of water weakens plants and make them more vulnerable to growth of the fungus.
This causes a major problems when the Aspergillus species growing on the crop starts producing toxins - something the fungus commonly does when it is stressed by - for example - low levels of moisture.
Fungal toxin levels allowed in crops such as peanuts and corn are strictly controlled by the authorities so the crops are tested rigorously prior to sale. Crops containing higher levels of toxin are worth less than crops with low levels of toxin - toxins cost the farmer money and reduce the amount of crops available for human consumption in the US. NB poorer countries have to buy in some of the cheapest crops they can find and they are often those with higher levels of toxin - thus introducing higher levels of toxins into their food system - this problem effects everyone around the world.
What to do? A simple solution has been investigated and found success - spray the crops and soil with a strain of Aspergillus that doesn't produce toxins! Crucially a strain of Aspergillus that grows more quickly than toxin-producing strains has been isolated and sprayed onto corn crops. At harvest time on sprayed crops no toxin has been detected compared with levels detected in neighbouring fields that exceeded admissable levels - a resounding success.
No chemicals, relatively cheap to produce and sustainable.