If you see squiggly lines on your container plant leaves, you may have an infestation of leaf miner pests. Leaf miners are the larvae of insects that live inside of and eat plant leaves. The squiggly lines are the damage created by the larvae eating the plant's leaf tissue, and experts can tell what species is eating the leaf by examining the squiggly line pattern. Most leaf miners are moths and flies. The damage can be quite extensive before the plant loses its vigor and begins to die. While leaf miners are not an immediate threat, their numbers can grow out of control and eventually kill your plants.
Leaf miners are commonly found on citrus tree leaves, azaleas, bougainvillea, chrysanthemum, boxwood and others. They are difficult to get rid of because they are protected by the plant’s leaves. First remove affected plant foliage (this will prevent the larvae from metamorphosing into adults in your garden), and then prevent them from coming back. While insecticide sprays can be used to kill leaf miners, some garden plants can attract these pests on purpose (columbine is one example) in order to keep them away from more prized plants, such as citrus trees. Either plant columbine next to your commonly attacked plants, or try to attract wasps to your garden.
Wasps are great for removing unwanted pests, including aphids, ants, caterpillars, leaf miners and more. If you have dense, lush plant growth with nectar-producing plants, wasps should come to your garden. You can also place water dishes outside to entice wasps to come and drink the water. They will lay their eggs in or on a leaf miner larva the affected leaves, and their larvae will eat the leaf miners inside of the leaves. A lot of people try to eradicate wasps from their gardens, but wasps are great gardening pals! They also will pollinate your plants and increase your fruit and vegetable yields.