Q. My hibiscus plants were looking bad— leaves yellowing and drying out, and the plant is sticky all over. I suspect whiteflies because I saw a bunch of very tiny insects hanging out near the base of the plant. What can I do to get rid of them?
Hibiscus is subject to whitefly infestation, so your guess is probably accurate. The adults are tiny white flying insects (the Giant Whitefly measures less than 0.2 inches in length) and are the most visible form, but the real damage is caused by the nymphs. They reside on the underside of leaves but are so tiny that they are barely visible, even under magnification. They can be translucent, white, or black in color, oval-shaped, and not motile. Similar to aphids, they damage leaves by sucking sap. As they feed, they exude sticky honeydew, which attracts ants and can foster black mold growth. They also can transmit viruses through their feeding activity.
If your plants are heavily infested, I recommend pruning them heavily and removing all dead leaves and detritus from beneath the plants. Hose off the leaves using the jet spray setting since this will remove many of the nymphs. Apply bait to control the ants that protect nymphs from natural predators. Local application of horticultural oil and/or insecticidal soap can kill whiteflies and their nymphs without affecting any target species.
Whiteflies, like aphids and other soft-bodied pests, are food for many predators (such as lady beetles, lacewings, minute pirate bugs, and big-eyed bugs). They are also a favorite host to numerous parasitoids. For this reason, you want to avoid broad-spectrum pesticides since they will kill the beneficials that keep pest populations under control. In fact, many whitefly infestations occur after application of these pesticides.
To avoid reinfestation, place reflective mulch under young plants, hose off plants to control dust, and avoid using broad-spectrum insecticides.
Q. I have a small yard with no room for a regular compost bin, but I do have a very small space where I’d like to grow a few veggies. How can I compost my kitchen waste without a compost bin?
You can simply bury your kitchen scraps directly into your garden soil. This works remarkably well, especially for small households. Just dig a hole, dump any compostable materials, and cover it up. Most ordinary kitchen scraps will break down quickly. Stinkier items such as shrimp shells or fish heads can also be composted this way, but I recommend digging a deeper hole to discourage digging by nighttime visitors.