Grow Q&A: Bugs Inside Pot Leaves (Leaf Miners)

Dear Dan, I’ve been growing indoors for twenty years and I finally found a problem I can’t solve. There are tiny green maggots inside my plants’ leaves! I’ve tried spraying with insecticides and dunking the plants whole into neem oil baths but these little suckers still persist. They dig pale yellow tunnels through the leaves and I can feel them in there just munching, pooping and screwing away. Please help me get rid of these annoying pests! – Horti-Cultured

Dear Horti,
Sounds like you have an infestation of leaf miner worms. Their huge appetites and short life cycle mean that their damage piles up fast. They bore into the leaf and “mine” the inside, leaving patches of infected areas between the ribs and they do look a lot like small maggots.

Spraying with insecticides isn’t likely to get to them as they’re well protected by the outer layer of plant material. Several applications of fungicide such as Organicide, will help curtail them a bit but sadly, one of the best ways to truly rid yourself of them is to physically crush them within the leaf. They’re easy to spot, like tiny caterpillars and you can pinch them pretty easily.

Remove and discard any leaves that show signs of leaf miner worm damage, as their tiny eggs and larvae are difficult to see. This will prevent future outbreaks. Another great option is to use predator nematodes, available online. They will hunt and kill your leaf miners even within the leaves and are a perfectly organic solution to your problem.

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