How are genetically engineered crops like AAA rated structured bonds?

Felix Salmon draws a clever analogy:

If you only grow one crop, the downside of losing it all to an outbreak is catastrophe. In rural Iowa it might mean financial ruin; in Niger, it could mean starvation.

Big agriculture companies like DuPont and Archer Daniels Midland (ADM), of course, have an answer to this problem: genetically engineered crops that are resistant to disease. But that answer is the agricultural equivalent of creating triple-A-rated mortgage bonds, fabricated precisely to prevent the problem of credit risk. It doesn’t make the problem go away: It just makes the problem rarer and much more dangerous when it does occur because no one is — or even can be — prepared for such a high-impact, low-probability event.