Posted by Nathan Houser on August 28, 2005

Q: I have a compost container where I compost fruit and vegitable scraps. For several years there has been a large family of red worms living in and no doubt under the composter (it sits on the ground). A few days ago I noticed great masses of larvae of some kind (either maggots or grubs I suppose—they are about half an inch long, possibly just a bit longer) swarming in the composter. I have no Idea what is going to hatch and wonder if I should try to eradicate them (but I'd hate to kill the worms). Any thoughts on this? Thanks.

Habitat: suburban/yard

State: Indiana

Habitat: suburban/yard

A: I'd leave the larvae (maggots?)alone. For one thing, they're helping to breakdown the foods you've placed there so they're really "helping" you. My guess is that you placed some food product in your compost that simply coincided with an insect's time to lay its eggs. This might explain why you haven't seen them before. Of course, insect populations do wax and wane so this may simply be a good year for this particular insect.

I do have an idea that you might want to try. Keep an eye on the larvae and when they advance into their pupal stage, put a few into a container(jar with a screen on top works well). Then when they emerge, you'll get to see exactly what they are. Incidently, if they're grubs (beetle larvae) you should be able to see a definite head and tiny legs. If they're maggots (fly larvae), they have no legs nor an obvious head.

Hope you're able to ID the larvae so you'll know if it ever happens again. Thanks for a good question.

John Wiessinger ( August 29, 2005)