Dear colleague,

Extraction of metabolites really depends on the nature of chemical compounds. For mass production, you may use autoclaved oat kernels for cultivation of fungi of interest. Single fungal species may produce many different kinds of metabolites. If the toxic compound is a hydrophobic small compound (e.g. polyketide), you could extract it simply by adding ethyl acetate to the culture. Further purification steps, such as TLC or column chromatography, may be required to isolate pure compounds from the crude extract.

I purified solanapyrones, pinolidoxin, or ascochitine produced by fungal pathogens, as described above. 

Mycotoxin is such very dangerous compound to use it to control plant pathogens or pests , because it caused chronic toxicity in low level and it very stable and not degradation for long time, So it is more dangerous than the pesticide, I dont recommended to use mycotoxin as pesticide.

You can follow standard methods of Mycotoxin extraction.

use the liquid media for the targeted fungus. and then put the flask in the shaker machine for some days. than you can use the centrifuge for extracting the fungus products.