It sounds like you have a serious infestation and if after using insecticide you still have pests the best tactic may be to just wait it out. I am not  sure what type of insect damage your plant is suffering from nor am I familiar with a plant called loufia. Perhaps you could send a photo or find out another name for your loufia plant. Sometimes a plant that is struggling will attract  insects or what you think are insects eating the plant are instead slugs, snails or even deer. A photo will help me to solve this mystery. Keep growing, Marianne Binetti