Grain can be traded in the futures market before harvest. If the rice production is predicted to be insufficient, the price of rice futures will rise; if the rice harvest is predicted, the price of rice futures will fall. Suppose this morning, Meteorologists predict that it will rain in rice producing areas tomorrow.  Because sufficient rain is very important to the current growth of rice, today's rice futures prices will drop significantly.
Agricultural experts announced today that a rice germ is spreading weakens the above view most severely.