The best control method consists of preventing the flies from laying eggs. Physical barriers such as row covers or netting of fine screening can be used for this purpose. The research shows that these can be as effective as insecticide application as long as it is placed over the crop immediately after the seeding (rutabaga) or transplanting (cabbage, cauliflower and broccoli). In order to be effective, there must be no gaps or tears in the material, the material must be placed over the crop before or immediately upon crop emergence or transplanting, and no hosts of the pests should have been grown on that site the previous year. It is also important to bury the edges of the netting so that cabbage maggot flies cannot get under the edges, and to allow the cover to be a little loose so the plants have room to grow.
Large commercial planting will have to be treated with insecticide for cabbage maggot. For more information please visit: http://www.agrapoint.ca/Pest%20Management%20Guides/Vegetables/2012/Cole%20Crops%202012.pdf
Given that the first generation of cabbage maggot was strong in 2012 it is fair to expect that the second generation which is less severe might be significant.
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| Rutabaga grown under netting. |
