Read up on natural insecticides and non-chemical remedies, and use chemical pesticides as a last resort. Identify the pest and use an appropriate pesticide. Many are non-selective, so beneficial insects will be affected, too. Improperly identifying a plant problem. Put your sleuthing skills to work to determine if the problem is caused by an insect, disease or environmental factor.
Insects harm plants by chewing, feeding internally or piercing and sucking.
Pathogenic diseases are caused by fungi, virus, bacteria or nematodes. Poorly adapted plants can be stressed by environmental factors such as poor soil preparation or conditions, too much or too little water, light or nutrients, or too much Texas heat. Be methodical in examining the damaged plant, do some research and use common sense. You'll likely get an identification and a suggested solution. Texas is a big state, and just because a plant is native to Texas does not mean it's native to your area.