The jatropha plant has traditionally been considered a weed, and it sure grows like one--it can thrive in marginal soil, requires very little water, and needs no fertilizers or pesticides. But it's currently one of the most hyped and desired weeds on the planet, as governments and companies all clamor over its potential as a renewable energy source. Attention focuses on the shrub's poisonous seeds, which are about 40 percent oil. New Zealand's biggest airline became jatropha's latest champion yesterday when it announced its intention of processing the seed oil into diesel fuel for its jumbo jets. Air New Zealand is hoping for a test flight in August or September, when it would fill one of the four engines of a 747 with the weed-derived fuel. Eventually, the company wants to get 10 percent of its total fuel from jatropha.