Publications for:

pest = Senecio vulgaris (weed)
crop = Onion/garlic/leek (Allium)

found 2 publications:

2002

Intercropping system optimization for yield, quality, and weed suppression combining mechanistic and descriptive models
Agronomy Journal (2002) 94 (4), 734-742
publishers website - pestinfo wiki

2000

Intercropping leeks to suppress weeds
Weed Research (2000) 40 (4), 359-374
pestinfo wiki