That is also something I am trying to figure out. Aphids sounded like the best way to start. I never realized how complicated and diverse the world of fungi and even aphids would be. Luv the challenge.
Here are the algea, fungal spores and rust spores I have discovered so far. It will be interesting to compare HDE/P ratios for our rural honeys.
https://drive.google.com/file/d/17erIS5sqro8kWR5GpA3XSFatGlAhYXUr/view?usp=sharing (Draft HDE Guide...) I am trying to recruit some specialists ( grad students) to help me identify the families  and genera if I am lucky so I can link them back to likely host plants and then determine if they are incidental or via sap sucking insect derived. This will likely become a never ending project. Great for keeping busy at -25C and below. We are finally in our deep freeze here. unfortunately we broke the -40C barrier a couple of nights ago.

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