Keeping the soil evenly moist at all times, and only watering when the top of soil has started to dry out, will prevent yellow leaves.
Wipe leaves with a damp cloth to remove accumulated dust or pop it in the shower for a while.
A little off the top! Adjust the height of your Dieffenbachia Maroba by removing the top of the plant if it grows too tall.
Light
Dieffenbachia enjoy bright, indirect light but can tolerate light shade. Lower light levels reduce the rate of growth and dull leaf variegation. Direct sunlight will scorch the leaves.
Watering
Water when the soil starts to become slightly dry at the top. Be careful not to overwater however; waterlogged roots can lead to rot or suffocate the plant.