Insecticidal Soap

• 1). Purchase an insecticidal soap at a local garden center or home improvement store. Made from naturally derived fatty acids, insecticidal soaps are safer than traditional insecticides. Read and follow all warnings and directions printed on the label. Each type and brand of insecticidal soap has its own set of specific instructions.
  
  
• 2). Spray the soap directly on the caterpillars. Look on the tops as well as the bottoms of leaves and on the plants' stems.
  
  
• 3). Repeat the process 7 to 10 days after the initial treatment.
  
  

Soapy Water

• 1). Mix 1 gallon of warm water with 1/4 cup of dish soap. Pour the mixture carefully into a garden sprayer.
  
  
• 2). Spray the soapy water on caterpillars on house siding, outdoor furniture and other nonliving items. Soak the insects completely.
  
  
• 3). Repeat the process whenever you see caterpillars. Alternatively, pick the caterpillars off the surfaces and place them in a bucket filled with warm, soapy water.