Could Fungus be cultivated or weaponized as a WMD, or have a major outbreak?

Lots of diseases were weaponized during the Cold War and WWII. Small Pox, The Plague, Ebola, Marburg, Anthrax, etc... are always brought up for diseases that could be used in war.

But I’ve never seen weaponized Fungus on a large scale outside of Science Fiction. Various Infections can be fatal and even have huge death rates with modern medicine. A large number of people still die from infections every year (albeit most in very poor areas).

Is it possible, without delving into ASB territory, for Fungus to be used as a weapon on a large scale for any culture, for a relative modern country to weaponized one, or for any Fungus with relatively natural changes to have a massive outbreak that can cause massive damage to a society by killing hundreds of thousands or more?
 
Fungal infections of crops? Stuff like club-root can persist in the soil for decades even without a brassica to feed off. Sclerotinia rot is damaging to most crops, and can live on for ten to fifteen years. Most fungi don't affect grains as strongly though, so it might not be as devastating as your looking for.

Potatoes can be hit hard by rhizoctonia infection, which was one of the major factors in the Irish potato famine. And could be affected by any fungus that targets tubers.

Do any of these fit the disaster you're looking for?
 
Fungal infections of crops? Stuff like club-root can persist in the soil for decades even without a brassica to feed off. Sclerotinia rot is damaging to most crops, and can live on for ten to fifteen years. Most fungi don't affect grains as strongly though, so it might not be as devastating as your looking for.

Potatoes can be hit hard by rhizoctonia infection, which was one of the major factors in the Irish potato famine. And could be affected by any fungus that targets tubers.

Do any of these fit the disaster you're looking for?
They might, I’m keeping a loose definition here.
 
I thought at first you were speaking of human fungal diseases as opposed to agricultural diseases. In the former case, most fungi metabolize too slowly and the victim has to be somewhat debilitated in the first place, if I recall correctly, for much harm to be done. (I'm ignoring such stuff as athlete's foot, jock itch, or barber's itch since those are nuisances rather than impairing, leaving aside any crude comedic possibilities.) True, Cryptococcus can be fatal, but to even get that in the first place conditions have to be just right. Long story short, as human pathogens, I think not--unless you're trying to get a population with itchy feet or crotch rot.
 
IIRC, in the past the US has somewhat seriously considered the use of rice blast fungus to destroy rice crops in Asia.

Synchytrium endobioticum,
a fungus that causes black scab in potato, is on the US federal bioterrorism list.
 
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