Onion

Scientific name: Allium cepa
Family: Alliaceae

Growth stages	Pests  For weeds and diseases please see further down on this page. For rodents, snails and slugs please click here
Seed
Seedling Stage
Roots	Onion fly
Stem	Armyworm Cutworm
Leaves	Aphids Armyworm Cutworm Thrips
Vegetative Stage
Stems
Leaves	Aphids Armyworm Leaf miner Spider mites Thrips
Reproductive Stage
Bulbs	Onion fly
Maturation stage
Bulbs	Onion fly

Weeds

Grasses
Sedges
Broadleaf

Diseases

Fungal
Bacterial
Viral

Agro-ecology

Do not plant onions after the field has been planted with other Allium plants. Field previously planted with corn should also be avoided because the same soil borne pests of corn will also attack onions (Boyhan; Kelly; Granberry, 2001: p. 24).

Proper seed selection is recommended to minimize problems of splits and doubles. Over-fertilization, uneven watering, and temperature fluctuations also influence double formation (Boyhan; Kelly; Granberry, 2001: pp. 11-12).

Soak seeds before sowing and seedlings before transplanting for 15 minutes in compost tea. Compost tea helps control many fungal pathogens and prevents spread of disease on healthy plants. To prepare you own compost tea, mix 1 part of well-done compost with 6 parts of water. Leave filtrate for 1 week. After straining, it is ready for use.
If bone meal is available, dust bone meal to roots to give seedlings a good start (Ellis; Bradley, 1996: pp. 155-158; 426-427).

Mulching onions with composted leaves and straws is highly recommended to maintain soil organic content, prevent soil borne disease, and suppress weeds. Planting onions in raised beds improves drainage and prevents damping-off (Ellis; Bradley, 1996: pp. 155-156).

Further information

Tolerant cultivars against onion leaf blight, onion smudge, Fusarium bulb rot and resistant cultivars against onion maggots/flies, aphids, and wireworm are now available in the markets. Also available are varieties with longer storage life. Ask for assistance from your local agricultural office for more information on such onion cultivars (CABI, 2000; CABI, 2004).

External links

• AVRDC. Crop production guides. http://avrdc.org/?page_id=2315
• UC IPM. Onion and garlic. http://www.ipm.ucdavis.edu/PDF/PMG/pmgoniongarlic.pdf
• Purdue University. Onion and its relatives. http://www.hort.purdue.edu/rhodcv/hort410/onions/onions.htm
• University of Minnesota. Onion arthropod pest management. http://ipmworld.umn.edu/chapters/straub.htm
• AVRDC. Suggested cultural practices for onion. http://libnts.avrdc.org.tw/web_crops/allium/culti_practices.pdf

References

• Boyhan, G.; Granberry, D.; Kelly, T. (2001): Onion Production Guide. College of Agricultural and Environmental Sciences. Cooperative Extension Service, University of Georgia.
• CABI. (2000): Crop protection compendium. Global module, 2nd edition. CABI Publishing, Wallingford, UK.
• Ellis, B.; Bradley, F. (1996): The organic gardener's handbook of natural insect and disease control. Rodale Press. Emmaus, Pennsylvania.
• Shanmugasumdaran, S. (2001): Suggested cultural practices for onion. Edited by T. Kalb. AVRDC Training Guide, AVRDC.