Diet composition

Mix:

• 2.5 g malt extract
• 44 g sawdust
• 10 g agar
• 2.5 g casein (may need to be dissolved in warm water)
• 5 g dextrose
• 2.5 g starch
• Literature recommends adding antibiotics at this step – it makes no difference, since you will autoclave this mixture anyway.

Add 200 ml tap water and mix thoroughly.

Autoclave mixture and pour in skinny long tubes while hot.

Press with something autoclaved, such as the inner part of a syringe, to squeeze out extra liquid.

After pressing media into tubes and letting solidify, have them freeze and defreeze – makes media more aerated.

Notes
Malt extract is pretty acidic, so most bacteria don’t grow there, so antibiotics are not really needed. The bigger problem are molds and mites. Washing beetles can help get rid of some spores, but the beetles come with a rich intestinal microflora and lots of spores anyway, so ultimately the only way to keep your colony from collapsing is starting anew, or re-establishing it with pupae reared on a pure fungus culture.
Mites can be taken care of by keeping your culture on insecticidal paper (available for example from Carolina Biological Company)