1. Abubakar L, Ado SG, Suberu HA, Magaji MD (2006) Screening of onion (Allium cepa L.) cultivars for resistance to purple blotch (Alternaria porri L.) disease. Biol Environ Sci J Tropics (BEST) 3(3):30–36
2. Arboleya J, Zandstra B, da Rocha A, Widders I, Hammerschmidt R (2003) Induced disease resistance and raised beds reduce purple blotch disease of onion. HortScience 38(5):763
3. AVRDC (2003) Asian Vegetable Research and Development Centre, Taiwan. Progess report for 2003, pp 1–10
4. Awad MA, El-Shenawy Z, Omran AF, Shatla MN (1978) Cultural practices in relation to purple blotch disease of onion. Sci Hortic 9:237–243
5. Bednarz F, Olarewaju JD (1986) Research notes on onion (Allium cepa L.) variety improvement in Nigeria. Paper presented at the 8th annual conference of the horticultural society of Nigeria, Ibadan, pp 10–14