@MsPalm, the issue with your Ruellia might be Mealybugs which feed on plant juices. They are commonly found in warm climates like here in Florida. When I see them on my plants, I take Q-tip swabs saturated in isopropyl alcholo and wipe them off stems and leaves but with a large infestation that can be rather time consuming so at those times I spray with Insecticidal Soap, which can be found at most garden centers.