Ask Mr. Smarty Plants

At the Lady Bird Johnson Wildflower Center, we are dedicated to plants native not only to North America but to the area in which the plant is being grown. There are 8 species of ruellia native to Louisiana, but none of them are those you are asking about, all of which are non-native hybrids, and therefore out of our range of expertise. However, we did do some searching for what might have been causing the holes in your plants, and it would appear the reason there is no information on pests and diseases for ruellia is that the general concensus is that it has no pests and diseases of any concern. One possibility that occurred to us is grasshoppers; we have observed in the past that they can be "hit and run" bugs, having a bite here and there but not hanging around. If they are not affecting your blooms, it would not seem you have much to worry about. You should also note that the ruellia is considered an invasive plant in many areas of North America, especially in the South. Read this article from Floridata on Ruellia brittoniana for more information.

Since we are neither entomologists nor plant pathologists, you might get better information from the Louisiana State University Research and Extension Office for Ouachita Parish.