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Cornell University

Swede Midge Information Center

Damage on Crops

Swede Midge Damage on Crops

Puckered and crinkled cabbage leaves
Puckered and crinkled leaves
Broccoli with puckered leaves showing drawstring effect
Leaf puckering can give a drawstring effect
Swollen broccoli petiole
Swollen tissue of leaf petioles/bases
Brown scarring on broccoli growing point
Brown scarring at the growing point
Distorted, twisted broccoli growing point
Distorted growing points including twisting
Bacterial rot on broccoli
Presence of secondary bacterial rots

Swede midge damage increases:

  • as the number of larvae feeding per plant increases
  • the earlier in development that the plant is infested (i.e. damage pre head formation is more damaging because it could result in blind heads)
  • later in the season as the population builds
  • in sheltered areas near hedgerows, buildings, treelines, etc. where populations tend to build