Kale root maggot (appearing end of June in southern Alberta)

Kale    South/Central Alberta

Noticed my kale plants starting to wilt. Variety is blue curled and all were healthy up til yesterday (about 2-3 weeks after setting out) Lifting a plant out of the earth shows several small white grubs (one third to one half size of a rice kernel) burrowing into the main root stem. No visible sign of activity above ground level. How can I get rid of or at least control these things. BT probably won't touch them as they seem to be only below grade and are attracted to the roots.
Many thanks in advance for any assistance - Robert in Southern Alberta

Posted by: robert stockwell (1 point) robert stockwell
Posted: July 3, 2017

Dr. Ravishankar Narayana commented,
It will be helpful if you upload images of damaged plants and grubs. Thanks
7 months ago.


Hi Robert, it looks like your plants are infested with cruciferous root maggots (Delia radicum). Generally the adult flies lay eggs on the stem near the soil. After hatching the white, legless maggots feeds on root resulting in wilting of above ground parts.
Did you have the same problem last year? If yes, it is advisable to follow crop rotation and also need a good soil preparation like deep digging to expose maggots and pupae to sun and natural predators. You can also use yellow sticky traps to monitor and control the adult flies. To control maggots drenching the soil with suitable insecticide is recommended. If you are buying transplants from nursery make sure they are free from eggs.


Posted by: Dr. Ravishankar Narayana (134 points) Dr. Ravishankar Narayana
Posted: July 7, 2017


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