Holes in carrot leaves

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on July 02, 2007 at 5:02 PM, updated July 02, 2007 at 5:04 PM

By George Weigel/The Patriot-News

Q: The leaves of my carrots have small holes right through the middle of the leaves. I researched the Web, but everything I found attacked the root, not the leaves. Is this an indication that something is also attacking my roots? I have sprayed with diluted neem oil for two weeks, but that hasn't seemed to help. Please suggest an organic friendly solution if you can identify what I am talking about.

A: I'd put my money on the flea beetle. These are dot-sized beetles that are best known for making tiny buck-shot-like holes in radish and beet leaves, but they also occasionally attack carrots.

You're right that most carrot pests are larvae that burrow into the roots themselves (especially the carrot fly). Carrot leaf injury is much less common, although a lot of it may go unnoticed since carrot leaves are small and lacy to start with.

To confirm my hunch, try waving your hand along the top of the row and see if any little round black dots jump off. If they're still active, rotenone is one of the best plant-based insecticides. I would've guessed neem oil would've at helped at least a little. Or maybe it did repel the beetles and what you're seeing is damage from a few weeks ago.

Some limited flea-beetle damage won't hurt. A bigger concern is that flea beetles sometimes spread diseases that can stunt carrot growth. Direct beetle damage isn't likely to do much harm - at least not like a rabbit or groundhog attack or an infestation of carrot-fly larvae.