Identifying Leaf Miners
While there are several different kinds of leaf miners, for the most part, their looks and plant damage is similar. Leaf miners tend to be non-descript, black flies. The flies do not directly cause damage to the plant; instead, it is the larva of these flies that causes the problems. Most of the time, this pest is identified by the leaf miner damage. Frequently, it appears as yellow, squiggly lines in the leaves. This is where the leaf miner larva have literally bored their way through the leaf. Leaf miner damage can also appear as spots or blotches.
Control Methods of Leaf Miner Pests
The most common method to rid plants of leaf miners is to spray general pesticide on the infected plants. The trick to this method of how to kill leaf miners is to spray at right time. If you spray too early or too late, the pesticide will not reach the leaf miner larva and will not kill the leaf miner flies. To effectively rid plants of leaf miners with pesticide, in the early spring, place a few infected leaves in a ziplock bag and check the bag daily. When you see small, black flies in the bag (which will be the leaf miner larva becoming adults), spray the plants daily for a week. There are pesticides that are specific to killing leaf miners by actually being absorbed into the leaves of the plant. These leaf miner specific sprays can be used at any time of the year. While pesticide is the most common form of control methods for leaf miners, it is not the most effective. Naturally kill leaf miners with beneficial bugs. You can purchase wasps called Diglyphus isaea from reputable nurseries. These natural enemies of the leaf miner will make a meal of the pests in your garden. Be aware that spraying pesticides can kill these beneficial bugs (and other less commercially available leaf miner predators you may have naturally in your garden). Another way of naturally killing leaf miners is to use neem oil. This insecticidal oil affects the leaf miner’s natural life cycle and will reduce the number of larva that become adults and thus the number of eggs that the adults will lay. While neem oil is not an immediate way how to kill leaf miners, it is a natural way to treat these pests.
