Insect pests can cause serious damage to your plants, eating foliage or introducing disease into the plants. Insecticide application is the most effective way to get rid of these harmful pests, but it may be dangerous, especially for indoor use. You can make your own natural insecticide to protect your indoor plants, reducing the danger to people and pets that come in contact with them.
Introduction of Pests
The most common way for insects to get on your houseplants is when they ride along on new, infested plants you bring into your home. Mealybugs and whiteflies, especially, almost always find their way to your houseplants in this way. You can help prevent pest infestations by giving new plants a careful inspection before buying them and by quarantining them in a separate room for three weeks before placing them near established houseplants.
The safest methods of removing insects from houseplants do not use chemicals and are most effective for mild infestations. Some insects, such as spider mites and aphids are easily dislodged when you shoot a strong jet of water on the plant with a syringe to wash them off. You can remove larger insects by hand-picking them off the plants, and yellow sticky traps placed near your houseplants can help reduce flying insects. Be careful when watering; soggy soil encourages insects such as fungus gnats, but plants placed in hot, dry areas can attract spider mites.
Plants naturally produce chemicals to protect themselves from plant-eating animals and insects and from diseases. These chemicals include pyrethrum and rotenone. Some plants also produce essential oils which, when mixed with pyrethrins, form insecticides that are less toxic than other chemical insecticides. You can find botanical insecticides at most lawn and garden centers.
You can also make your own houseplant insecticides from natural ingredients; one recipe contains garlic and soap. Peel the cloves from 1 head of garlic, and puree them with 2 tbsp. vegetable oil and 2 cups water. After letting this puree sit overnight, you can strain it through a piece of cheesecloth into a bowl. Add 1 tbsp. dish soap to the liquid to help it stick to your plants; just mix it well, pour it into a spray bottle and spray on the affected plants. Be sure to hit any visible pests with the mixture when you apply it.
Hot Pepper Insecticide
A stronger natural insecticide uses hot peppers instead of garlic. For this recipe, you should puree 1/2 cup chopped hot peppers such as jalapenos with 2 cups water and let the puree sit overnight. The next day, strain the mixture through a piece of cheesecloth. You may want to wear rubber gloves for this step, as the pepper mixture can burn your skin. Once the solid portion of the peppers is strained out, add 2 tbsp. dish soap, pour into a spray bottle and apply to your houseplant pests.