Can you provide evidence that the Beauveria bassiana fungus is an effective treatment? It's not that I don't believe you, it's just that I'd like the evidence to be self-contained in this post.
Interesting. I note that I would be weary of introducing a fungus that can spread within my house, without doing due diligence.
It depends a lot on the fungus lifecycle. If it's an obligatory insect parasite, then it won't do anything anywhere else, so it won't really spread other than to other insects. A quick look at Wikipedia says that it attacks arthropods with different strains showing different ranges, with some only attacking selective species, and others being a lot less discriminate. So you don't have to worry about it causing mold or infecting humans or (invertebrate) pets or plants. There were at least seven noted human infections in people with a suppressed immune system, but I'm guessing that if you're in that situation you'd be a lot more paranoid anyway.
The spores could potentially cause allergy issues, though Aprehend claims that it's fine.
Bed bugs are quite resistant to almost all pesticides; chemical extermination usually fails. Heat treatment works, but you need to heat infected areas to at least 120F. This can be pretty expensive. Landlords are required to pay for bedbug extermination, but they can opt for ineffective chemical treatment. Bedbugs are surprisingly hard to spread but are fairly resilient.
Luckily the Beauveria bassiana fungus is an effective and cheap treatment. Spores spread where bedbugs will come into contact. Once they germinate, they kill the bedbugs. Spores spread from bug to bug. They also disperse into the environment and survive well as long as the environment is sufficiently humid. The spores can be made more durable by simply mixing them with mineral oil.
The brand name Aprehend is Beauveria mixed with oil. There might be a cost-effective provider in your area you can pay to treat your home. However, DIY is very cheap. You can just buy Aprehend from diypestcontrol and spread it yourself. An even cheaper option is to buy Beauveria online and mix it with oil yourself.
Unless bedbugs evolve resistance or the government restricts DIY, bed bugs are a solved problem.
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