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Leaf Miners

Leaf Miners

Liriomyza and Pegomya spp.

Insectalso: Leafminers, Spinach leafminer, Beet leafminer

Tiny fly larvae that live and feed between the upper and lower skin of a leaf, scribbling pale, winding tunnels or blistered blotches as they go. On leafy greens like spinach, beet, and chard the mined leaves are unappetizing, but on most plants the damage is more cosmetic than serious.

🔎 How to spot it

The damage is unmistakable: pale, meandering, whitish tunnels (mines) that snake across the leaf, or papery blotches, with the tiny legless maggot visible if you peel the leaf apart. The adults are small gray flies a few millimeters long. Look for neat rows of small white eggs laid on the undersides of leaves, which is where to stop the next generation.

🥀 Damage it causes

The larvae tunnel through the inner leaf tissue, leaving winding white trails or blotches that reduce the leaf surface and make leafy greens unmarketable. On vigorous plants grown for their roots or fruit the damage is mostly cosmetic, but on spinach, chard, and beet greens the mined leaves are the part you eat.

🛡️ Prevent it

Cover susceptible greens with fine insect netting or row cover from the start to keep the egg-laying flies off, sealing the edges. Inspect leaf undersides and rub out the rows of white eggs, and pick off and destroy mined leaves before the larvae mature. Clear out weed hosts such as lambsquarters and chickweed that harbor leafminers nearby.

🧯 If it is already here

Remove and destroy mined and egg-laden leaves as soon as you spot them, which on a few plants keeps numbers down. Sprays are largely ineffective because the larvae are protected inside the leaf, and broad-spectrum insecticides do more harm by killing the parasitic wasps that usually control leafminers. Lean on those natural enemies and tolerate light, cosmetic mining.

💡 Good to know

Leafminers are usually held in check by tiny parasitic wasps, so they rarely need treatment except on leafy greens you eat. Several different flies, and a few moths, produce similar mines on different crops, but the look of the damage and the control, exclusion and removal, are much the same across them.

🌱 Plants it attacks

714 plants in the library can be attacked by this pest

Acorn SquashAdirondack Blue PotatoAdzuki BeanAfrican Blue BasilAfrican MarigoldAgapanthusAgeratumAgrimonyAji Amarillo Pepper🍓Albion StrawberryAlice du Pont Mandevilla🥔All Blue PotatoAlmondAloe VeraAmbrosia CornAmerican BasswoodAmerican Beauty Dragon FruitAmerican BeechAmerican PersimmonAmethyst Falls WisteriaAmish Paste TomatoAnaheim PepperAnemoneAngelique TulipAngeloniaAniseAnise HyssopAnjou PearAnnabelle Smooth HydrangeaAnnual VincaApeldoorn TulipApple MintApril Tryst CamelliaArbequina OliveArizona Sun Blanket FlowerArkin CarambolaArmenian CucumberAroniaArp RosemaryArugulaAshwagandhaAsian PearAsian PersimmonAtemoyaAtlantic Giant Pumpkin🥕Atomic Red CarrotAucubaAugust Beauty GardeniaAunt Molly's Ground CherryAutumn Joy SedumAvocadoBachelor's ButtonBalsam FirBalsam PoplarBanana PepperBarbara Karst BougainvilleaBartlett PearBay LaurelBayberryBeach PlumBeauregard Sweet PotatoBecky Shasta DaisyBee Balm🍅Beefmaster TomatoBenarys Giant ZinniaBengal Tiger CannaBetter Boy Tomato🥬Bibb Lettuce🍅Big Beef TomatoBig Boy TomatoBilberryBing CherryBitter MelonBlack BeanBlack Beauty EggplantBlack Beauty ZucchiniBlack Beluga LentilBlack Cherry TomatoBlack CrowberryBlack Currant🍉Black Diamond WatermelonBlack Kabouli ChickpeaBlack Krim TomatoBlack RaspberryBlack Sapote🥬Black Seeded Simpson Lettuce🥕Black Spanish RadishBlack Tartarian CherryBlack WalnutBlack-Eyed PeaBlack-eyed Susan VineBlood OrangeBloomsdale SpinachBlue Bird DelphiniumBlue Bird Rose of SharonBlue FescueBlue Lake Green BeanBluecrop BlueberryBocking 14 ComfreyBok Choy

For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.