Mustard is rarely infested. The turnip aphid typically infests mustard, radish, shepherdspurse, turnip, and watercress. It also injures other crucifers, particularly in their seedling stage. Damage - Aphids cluster on the underside of leaves and suck sap causing infested foliage to curl, wilt, or become distorted. In North Carolina, cabbage and turnip aphids continue to feed and breed at reduced rates throughout the winter.
Collards are an important overwintering host plant.
As warm weather returns, aphid activity increases. Periodically, winged females develop and fly to new host plants. Favored by moderate temperatures and dry weather, reproduction continues in this manner throughout summer. As many as 30 to 45 annual generations occur along the Gulf Coast though not quite so many are produced in North Carolina. Plant the crop in a well-prepared, fertile seedbed to promote vigorous growth.