You're right. I looked a little more on their site and found:

The policies are reinsured by Swiss RE Corporate Solutions Ltd which also has an A.M. Best rating of "A+" (Superior).

It looks like Swiss Re has a pretty significant global crop insurance business.

http://www.swissre.com/reinsurance/insurers/agriculture/

edit: I'm still a little confused though. What is the point of developing their own sophisticated risk model when the price of the policy will ultimately depend on Swiss Re's risk model?