Flying insects like houseflies and mosquitoes can be annoying if they find their way into your house. Although they will not harm your houseplants, other flying insects can be very destructive. Whiteflies, fungus gnats and adult thrips can present you with a challenge if they attack your indoor plants. Prevention is the best medicine for many insect pests: examine your plants frequently and make sure your window and door screens have no holes. Natural remedies can provide good protection and can trap or kill many flying insects.
Keeping Flying Insects From Your Houseplants
Examine plants before you buy them. The University of Minnesota advises houseplant growers that preventing an insect invasion is the best cure. Even if you see no signs of insects or insect damage on new plants, don't bring them into your house for two or three weeks. If you put any plants outdoors in the summer, examine them closely for flying insects or insect eggs before you bring them indoors for the winter. Washing your smooth-leaved houseplants with a soft, damp cloth is a good practice to remove tiny eggs or larvae that might hatch into a nuisance flying insect.
Plant your houseplants in sterilized potting soil that drains quickly. Some insects, such as the fungus gnat's larvae, live in damp soil or underneath pots. Examine your plants every time you water them and make sure no small worms are living between the pot and its saucer. Allow plants to dry thoroughly before you water them and apply the natural soil bacterium called Bacillus thuringiensis (Bt) if the larvae of adult flying gnats are numerous.
Spray plants with insecticidal soap if you notice any type of flying insect in their vicinity. Insecticidal soap is a natural remedy available at garden shops everywhere. It's wise to move your plant outdoors when you spray, or protect your carpet, walls and other household items with an old sheet or blanket. Insecticidal soap is most effective if you spray your plant every other day, and continue spraying until all signs of the problem insect are gone. Watch your plant closely and resume spraying if insects return.
Hang yellow sticky traps near your affected plant. These traps are available at garden supply stores and are nontoxic--the sticky substance traps flying insects such as whiteflies and does not allow them to become free. For the best effectiveness, use several traps in the area around your affected plant.