How to Control Leaf Miners in Your Garden

If you’re not careful or fail to plan ahead, you may unintentionally put your crops at risk. Leafminers aren’t typically threatening to plants.


However, the effects of their presence could cost you hundreds of dollars in crop value! So, what the heck are leafminers and how do they have so much control over the success of your crops?

What is A Leafminer?

First things first. What is a leafminer? Leafminers are the larvae of different insects that feed on the soft tissue of various plants.

This includes flies, beetles, moths, and basically any other bug that can be found in the base or upper portion of a plant. Sounds kind of gross, right? In reality, this is actually a pretty common occurrence amongst farmers or horticulturists.

Leafminers are actually pretty similar in appearance. They can be characterized by their size, shape, and color. The maggots of leafminers are usually about one-third of an inch long.

They can often be mistaken as a caterpillar or a small worm. As far as the color, they are masters of disguise! They will attempt to blend into the plant, with a pale yellow or green hue to them.

Identifying Leafminer Damage

If you’re researching leafminers, odds are, you’ve already noticed some damage to your crops, or garden. When several factors can wreak havoc on your plants, how do you know it’s leafminer damage? Some of the biggest warning signs of leafminer damage can be identified by:

  • Fungus or bacteria growth on plants
  • Yellow and drooping leaves
  • Distinct white zig-zag lines on top of the leaf
  • Brownish colors in the winter
  • Weak leaf tissue

It’s important to keep in mind, the effects of leafminers vary from plant-to-plant. On bigger, heavier-leaved plants, leafminer damage may be more difficult to detect. With these, leafminers are not considered ‘fatal’ to the plant. However, visible negative attributes may make the plant a bit more undesired.

When it comes to smaller plants, the effects of leaf-mining can be fatal. When leafminers burrow themselves in the leaf tissue or tunnel to extreme extents, smaller plants just don’t stand a chance.

Please note that a majority of the plants affected by these crawlers include spinach, beets, eggplant, cucumber, potatoes, lettuce, etc. Basically, anything that appears to be leafy and fresh, is a full-course meal for leafminers.

Fixing Damage from Leafminers

If you’re looking for a way to fix an already existing issue, you may be out of luck. Rescuing your crop depends solely on the amount of damage already done.

It is rare that damage has exceeded the point of no return. Considering you’re in the best-case scenario, here are a few ways to bring new life back to your crops.

1. Try Switching to An Organic Fertilizer

Typically, if the plant is healthy, there is less of a chance that leafminers will be able to take over. While acting as a natural leafminer deterrent, organic soils are usually better for your plants and crops.

As a bonus, they aren’t much more expensive than regular fertilizer either. It may also be helpful to implement compost and other soil minerals.

2. Invest in Overhead Protection

If you’ve been a farmer or horticulturist for a while, you’ve likely heard of floating row covers. Floating row covers are one of the most budget-friendly options when eliminating leafminers.

A floating row cover is essentially a sheet, or netting, draped over crops, deterring bugs from landing, and potentially laying eggs.

Additionally, if you’re new to gardening, it is wise to ask a local gardener for some tips. They usually have the best grip on planting in the area, and the best cover to use for certain plants.

3. Use Parasitic Wasps

Parasitic wasps are one of the most effective ways to keep smaller bugs out. This one may sound a little bit ‘iffy’ for those of us who aren’t comfortable with flying insects.

However, parasitic wasps are sold commercially, and do not pose a threat to humans. Although, if mishandled, or treated improperly, they do have the ability to sting. Handle with caution!

4. Insecticides (As a Last Resort)

This form of control method should only be used in severe circumstances. You risk chemical damage to your plants, just for the sake of leafminer removal. The use of pesticides, or insecticides, could possibly have an adverse effect on the photosynthesis process.

Additionally, pesticides can kill off bigger bugs, which help to remove the smaller ones. Ultimately, it is up to you to decide if this is the most suited for your situation.

In the cases of extreme damage (trust me, I hate saying this), you always have the option to start fresh. A ton of hard work goes into building a crop or working on a flourishing garden. However, if you find yourself feeling helpless, having tried every method to get it under control, it may be the only option.

Leafminer Control in the Future

Once you’ve gotten your insect issue under control, it is almost mandatory to have an effective follow-up routine. In fact, many horticulturists recommend it. After all, why waste time removing the situation, if you don’t plan to stay on top of it?

Three more popular forms of follow-up treatments are the use of neem oil, cypress planters and ‘squashing’ the problem...literally.

Neem Oil

You may have heard of neem oil to treating several different health issues, including acne. However, neem oil serves an even bigger purpose for gardeners and farmers. Neem oil, taken directly from the Neem tree, is a product applied to plants in spray-form.

Despite popular belief, neem oil is actually an organic, and completely natural, insecticide. Azadirachtin, the most active ingredient in the oil, is the main reason this works for insect repelling, and pest killing

Insect Killing

I know, I know. This sounds a bit intimidating. However, I can assure you, it is an easy process. Particularly favored among those who do prefer not to use any sort of chemical follow-up, you can kill the larvae.

When you notice larvae tunneling, you can squeeze the plant at the tunnel, as gently as possible, and squash any possibility of outbreaks. Please note, this method of treatment requires heavy monitoring.

Cypress Planters

Cypress planters are great because they’re naturally pest resistant. Started by Paul and Jody Baker in New Port Richey Fl, Dirt Don’t Hurt Graden Company makes custom cypress planters for any garden size.

At the end of the day, your main goal is producing and selling a good product. If you should choose to neglect the prevention of leaf-mining insects, your business may suffer. If you learn how to effectively control leafminers, your garden will begin to heal.

Author Bio: Lindsay Engle is the healthcare expert at MedicareFAQ, a learning resource center for senior healthcare. Lindsay loves working in the healthcare industry, especially with seniors. Aside from her job, she has a great passion for animals and loves boating. In her spare time, she enjoys snuggling on the couch with her pets as well as fishing with her boyfriend.

About the Author Laura Bennett

Hello, I’m Laura Bennett. I love nature especially when it comes to flowers and different kinds of plants. I started a very small garden behind my house and I named it Humid Garden. So, I created this blog to provide aspiring and inspiring thoughts about gardening for gardeners and anyone who has the intention of keeping a garden.

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