Until their algae strategy is fully implemented, we are indeed somewhat at the mercy of crop prices. However we're seeing a similar rise in the price of crude oil, which is the counter-threat (or in the case of it rising, "opportunity").
I believe crude prices will only rise over the long term, outpacing crop prices. But I hope to hear some good news on the algae front soon.
I watched the Australian documentary "Crude" last night -- gives a very informative overview of oil, our use of it, and the future availability of it. It bodes extremely well for the bio-plastics industry.