A few months ago, I started a small lanai garden. I planted edibles such as basil and mint, and also added a Monstera plant so I could have a steady stream of fresh foliage to use for decor around the apartment. Things were going well, but then not too long ago, I started noticing little whiteflies fluttering about whenever I watered or touched my plants.
These little pests feed on the underside of plant leaves, making my green lanai garden the perfect place for them to live. To deal with the problem, I splashed water all over the tops of the plants when I watered them, but that didn’t do the trick.
I consulted horticulturists and home-gardening enthusiasts. I got some good advice and was also pointed in the direction of the University of Hawaii’s College of Tropical Agriculture and Human Resources (CTAHR), which has an abundance of information on virtually anything having to do with agriculture. It turns out that dealing with whiteflies can be quite simple, and there are a variety of things you can try.
• Add water. Squirt the undersides of leaves with water, especially for trees or larger plants for which spraying with insecticides might seem unreasonable. Use a strong spray, and remember to concentrate on the underside of the leaves.
• Opt for organic. Spray the plants with insecticidal soap or neem oil, both of which should be readily available at gardening centers and home improvement stores such as City Mill. For added oomph, spray the plants down with water (especially the underside of leaves) and allow them to dry before applying.
• Make your own concoction. Mix gentle liquid dish soap with water (about 2 tablespoons to 1 quart), and spray directly onto the plants. Avoid using detergents or soaps with anti-bacterial agents, as they may be harmful to plants.
• Go yellow. If the infection is light, place yellow sticky cards near the plant. The color attracts the flies and the stickiness will keep them on the cards. You can find these cards at garden centers and home improvement stores.
• Attack the ants. Believe it or not, ants actually “farm” whiteflies so they can eat the honeydew the flies secrete. Try experimenting with different types of bait, as my horticulturist source tells me that some ants are more attracted to protein, while others are drawn to sweets.
Finally, inspect any new plants before introducing them to your garden. For existing plants, examine them often and remove leaves when the infestation is heavy.
Have a comment or question for Joanne? Email thefixisinhawaii@gmail.com.