How To Rid Plants Of Leaf Miners

Leaf miner damage is unsightly and, if left untreated, can end up causing serious damage to a plant. Taking steps to rid plants of leaf miners includes keeping plants healthy and properly cared for.

Mark On A Leaf From A Leaf Miner Insect
(Image credit: Nickel_Bell)

All About Leaf Miners

Leaf miner damage is unsightly and, if left untreated, can end up causing serious damage to a plant. Taking steps to rid plants of leaf miners will not only make them look better but will also improve their overall health. Let's take a look at identifying leaf miners and how to kill leaf miners.

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. Consult with your local extension service agent before using chemical controls, as they can be harmful to the environment. Other effective alternative methods may be available, such as beneficial bugs like wasps.

While pesticide is the most common form of control methods for leaf miners, it is not the most effective. We recommend killing leaf miners naturally 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.

Heather Rhoades
Founder of Gardening Know How

Heather Rhoades founded Gardening Know How in 2007. She holds degrees from Cleveland State University and Northern Kentucky University. She is an avid gardener with a passion for community, and is a recipient of the Master Gardeners of Ohio Lifetime Achievement Award.