A. assectella is a moth present throughout Europe. It is also found in some Asian countries and has been introduced in parts of Canada. The larvae of A. assectella feed on cultivated species of Allium, mainly leek (A. porrum) and onion (A. cepa), but also garlic (A. sativum) and chive (A. fistulosum and A. schoenoprasum).
The vegetative and flowering stages are the most affected, but the seedling stage is sometimes affected in nurseries. The stored onions and garlic are also damaged.