The infected papaya trees will produce less carbohydrates or chemical energy for the toucan. If there were fewer carbohydrates within each papaya, the toucan's muscle cells would not be able to obtain as much chemical energy as they normally do. This chemical energy will be converted into mechanical energy or heat flow, which the toucan uses to fly.
Therefore, the lower amount of mechanical energy and heat flow from the muscle contractions, it would result into a reduced amount of kinetic energy of motion when the toucan is flying.