How To Fight Leafminer Insects

Leafminers are the larvae of what will eventually become a moth, beetle or fly. Mature insects lay their eggs on the leaves of various plants because the leaves of the plant are a life source that provides both nutrients and shelter for their undeveloped offspring. The larvae then tunnel through the leaf itself, leaving a trail behind them that looks like a squiggly line. If you look closely, you can actually see the larvae, a dark spot at the end of the path they’ve been tunneling.

Leafminers are true to their name.They are mining nutrients from your crops. Those squiggly lines that they leave behind them as they eat their way through are actually empty spaces inside the leaves. When the leafminer is done with a leaf, there is nothing left but a skeleton.

If you have a leafminer problem, you need to act fast before it’s too late, because lots of leaves covered with those squiggly lines is a sign that your plant is not long for this world. Unless you can figure out a way to rid your garden of leafminers, you could lose crop after crop due to these persistent pests. Read on to learn about proven methods of fighting leafminers and taking your garden back for good.

Beneficial Bugs

While spraying chemically-based pesticides on your plants may seem like the easiest option for getting rid of pests, pesticides can also drive away beneficial insects that protect your plants from harmful insects and other calamities. Investing in some wasps at your local nursery is one all-natural way to get rid of leafminers.

The wasp species Diglyphus isaea consider the leafminer to be a delicacy and will make a meal of the pests until the problem is rectified. The wasps start by stinging the larvae, paralyzing them immediately, which stops the tunneling in its tracks.

As if that wasn’t enough bad news for the leafminer, the Diglyphus doesn’t stop there. The wasp then lay one to five eggs next to the paralyzed larvae. Both the adult wasp and the wasp’s offspring then feast on the leafminer larvae, eating it alive while it can’t move to defend itself, from the outer layers to the center, until nothing is left of it. Only the trail it created from eating through the leaf remains as evidence that there was ever a problem.

Neem Oil

Neem oil is another natural way to deal with a leafminer infestation and to protect your plants from future outbreaks. Though spraying neem oil doesn’t immediately kill all the adult leafminers,it does give them a rough time, keeping them from flying, mating and even eating. So, neem oil is not an instantaneous solution, but it does the trick in the long run, suffocating the insect and altering their life cycle so dramatically that they eventually die off from a lack of procreation.

White Oil

To make white oil, you will need a spray bottle for treating your plants with the all-natural concoction, preferably one that holds 500 mL, 1 teaspoon of vegetable oil, and one teaspoon of dish soap, and just under 500 mL of water. Mix the ingredients together and stir until the mixture is consistent. When spraying down the affected plants, be sure not to overdo it. A light coat of white oil is all you need to keep the leafminers at bay. Make sure that each leaf of the affected plant is coated evenly on both the top side and underside.

The white oil treatment works in the same way as the neem oil spray, it suffocates the leafminers and keeps them from mating, eating through the leaves of your garden’s plants, and flying from leaf to leaf in search of more foliage to decimate. White oil doesn’t kill leafminers swiftly, but it does stop them from doing any more damage than they already have. Use this video tutorial on how to make and apply white oil to fight off leafminers.

Row Covers

Select each leaf that has leafminer tunnels or visible eggs on them. Shield them with white floating row covers to stop the leafminers from spreading and doing further damage to other blades on the plant. Row covers can usually be found and purchased at garden centers or farm stores. This containment method should only be used if the infestation is still small. If the plant is covered in leafminer tunnels on nearly every leaf, it’s obviously too late to attempt a containment plan.

Because they are protected inside of the leaf by the outer layers of the leaf itself for most of the larvae stage of their lives, leafminers are quite hard to kill with pesticides. Pesticides also kill the predator insects that snack on leafminers before they can destroy your plants. Also, chemical sprays are only a legitimate option if you have leafminer problems on ornamental plants, as you don’t want to use pesticides on or near plants that you have no intentions of using culinarily.

Learn more about Leaf Miner Control

Better Homes and Gardens

Gardening Know How

Green Methods

Plant Care Today