Leaf Miners: How To Identify & Get Rid Of Them

Leaf Miners

The first time I saw Leaf Miners had caused what appeared to be extensive damage to my plant leaves I had no idea what to think. It looked like someone had painted on them with a marker with all those white markings. It was weird it never dawned on me that it could be an insect doing that to my plants.

Then I found out there were many insects that exhibit the same behavior, there are even citrus pests called citrus leaf miners. They are drawn to citrus fruits trees like orange trees and other citrus plants. I found out when my neighbor’s saw the same damage on her lemon bushes. Luckily they are treated the same way, so that makes it easy because you don’t have to identify the exact leaf miner you have to treat for it.

Do your leaves look like someone has drawn squiggly lines on them? If your answer is “yes” then you’re most like dealing with leaf miners. Today, we’ll be talking about how you can identify this common pest and control them in the garden. Let’s get started!

Identifying Leaf Miners

The term leaf miner refers to the larva of several species of insects that feed on the leaves of plants such as serpentine mites. These larvae feed inside the leaf tissue and leaf margin and selectively eat the upper and lower edge of the leaf as well as the leaf surface of those that have the least amount of cellulose. 

Leaf miners become active in early spring, laying eggs soon after flushes of new growth, young leaves, and growth of young trees start.

Adult citrus leafminer and other leaf miners lay their eggs inside leaves. Once these eggs hatch, they begin to tunnel around inside the leaves creating the characteristic of wavy lines or silvery trails that you’ll see on leaves affected by this pest. Most of these pests have hind wings.

Many insect species have leaf-mining larvae such as:

• adult moths (Lepidoptera) or (phyllocnistis citrella stainton)
• sawflies (Symphyta, the mother clade of wasps)
• flies (Diptera)
• Some beetles can also exhibit this behavior.

Types Of Leaf Miners

• Serpentine mites
• Citrus peelminer they can be found in southern California
• Maggots of true flies
• Soft Fly Larvae
• Beetle Grubs
• Weevil Grubs

Leaf Miner Damage

Leaf miners can feed on a wide variety of crops including plants in the spinach family such as Swiss chard and beets. They can also feed on cucumber, celery, eggplant, lettuce, peas, potatoes, lime tree, lemon tree, and tomatoes.

In some severe cases they may also chew their way through shrubs and trees including citrus fruit as I mentioned above.

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As leaf miners bore through the leaves of plants, they leave a “mine” that appears as yellow squiggly lines. Sometimes, they won’t zigzag their way through a plant, however. Instead, they will leave behind brown blotches.

Most of the time, the damage caused by leaf miners is purely cosmetic. The unsightly trails they leave behind make plants look unattractive. However, in repeated or severe infestations, the stress they cause to the plant can weaken them and cause them to die. 

Controlling Leaf Miners

Leaf miners can be tricky to control and manage since they live inside the leaves of your plants. Most insecticides aren’t effective since the pests are protected by the outer layer of the leaves.

Meanwhile, systemic insecticides that can kill leaf miners tend to be absorbed by plants and are not ideal for edible crops.

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There are, however, certain things you can do if you see signs of leaf miners in your garden. This includes:

• Squeezing leaves to kill larvae. As soon as you see wavy lines on the leaves of your plants, give the leaves a squeeze to get rid of the larvae.

• Remove infected leaves and discard them. Doing this will prevent any further damage that can be inflicted on the rest of the plant.

• Use trap crops to keep leaf miners away from your valuable plants. Use plants like columbine, lambs quarter, and velvet leaf to attract leaf miners.

• Use beneficial insects such as parasitic wasps to help in controlling leaf miner populations in your home gardens. Adult wasps can get into the tunnels created by leaf miners and kill them. Meanwhile, their pupae can feed on dead leaf miner larvae.
• Use neem oil this organic insecticide 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.

• Use pheromone traps such as yellow or blue sticky traps to attract leaf miners. These are a great tool since adult leaf miners can get stuck in the adhesive leaving them unable to mate or lay eggs.

What is the insect that is causing you the most aggravation in your garden?