Onion Maggots
Onion maggots are very small measuring around 9mm. The adult is a fly that is about 9mm long, greyish coloured with large wings.
Onion Maggot-Later’s, Maggots & Pupae-Jack Kelly Clark
Description
Onion maggots are very small measuring around 9mm. The adult is a fly that is about 9mm long, greyish coloured with large wings. They lay their eggs around the base of onions and garlic in the spring after they emerge for overwintering pupae. Eggs hatch and the larva feed on the onions. The maggots can feed for up to 3 weeks before they become a soft brown pupae.
Onion Maggot Flies-Manitoba Agriculture, Fly, Larva and Pupae-University of Maine
Habitat
They are found in cooler damper areas. Cool coastal climates are where they are prevalent. You can find these guys near dandelions and edge weeds around the garden.
Damage
Plants turn yellow and the maggots hollow out the whole onion if given a chance. Large bulbs will rot. Destroy all affected plants.
Maggot damage on onions-University of California
Control
1) Sticky Traps
Yellow sticky traps will capture the flies in the spring. Tanglefoot is a good organic substance that can be safely sprayed or spread on stems and catches anything that climbs up.
2) Plan Your Planting Times
When planting onions and garlic in cooler climates, like the Pacific Northwest, it would be best to either plant in february when the flies are not present or wait until after the spring hatch of the flies. (mid-May) If you live in the Pacific Northwest there are several types of green onions that will thrive in the winter.
3) Rotate Your Crops
Pupae overwinter in the ground where the affected plants are, so rotating will give you a head start on controlling these guys. Clean up all garden debris before you close your garden for the winter.
4) Wood Ashes
Sprinkle wood ashes and cayenne pepper around the plants to discourage egg laying. Be very careful what ashes you use. Ashes from your wood stove or fireplace are the best choice. Be sure that wood has not been treated with chemicalss and that nothing other than newspaper was also burned. Coated papers, cig butts, and other things tossed in the fire can contaminate your crops. Know where your ashes came from before you apply.
5) Build Raised Beds
These guys love poorly drained soil, so a good idea would be to plant your onions and or garlic in raised beds.
March 3rd, 2008 at 4:59 pm
When I lived in northern Utah I was told that the pests in my radishes were onion maggots, and they looked very much like those pictured above. Does this make sense? Since I moved to the hot deserts of Arizona I have not had any problem with them in either my onions or radishes. Do they not exist in this climate?
June 26th, 2007 at 7:49 pm
Not really. If you let your onions go to seed and flower then I suppose pollination would be beneficial.
Regards
Cahri
June 26th, 2007 at 7:04 pm
I would like to know if the pollinators are a concern when we are dealing with onions.?hankyou
June 25th, 2007 at 11:46 pm
This depends on your area. If you are still awaiting summer heat then you should leave them on for a few more weeks. These guys are finished when the heat turns on. Remember though that you need to remove the covers so that your pollinaters do thier jobs.
Regards
Cahri
June 25th, 2007 at 11:00 pm
I have covered my onions with a garden fabric and it has worked very well.I am hearing that the flies lay their eggs from spring until fall.Is this true??I would like to soon take the fabric off.thankyou.
June 4th, 2006 at 11:34 am
Could you tell me why the tops of my onions turn white?
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