Consider effective options that will not harm the environment. A cluster of aphids on a cattleya shoot can be carefully wiped off with a cloth soaked in sudsy warm water. Dab away mealybugs lodged in a bloom sheath with a cotton swab dipped in alcohol. Diatomaceous earth sprinkled on the medium discourages snails and slugs. Occasionally it is necessary to rely on a chemical, especially when many plants are involved.
Some growers plan regular spray programs to control insects and diseases.
Before spraying, be forewarned that some chemicals will damage flowers. Frequently repeated applications are necessary to eradicate all traces of an insect. Make sure no people or pets are in the area. Keep them away from the spray site for 24 hours. Move orchids grown indoors to a well-ventilated area.