Welcome, onion warriors, to the ultimate showdown against the villains of the onion world! At Onion Doctor Limited, we are your trusty sidekicks in the quest to grow onions so epic they would make a chef weep with pride. But lurking in the shadows of your Onion Farms in Kenya, is a deadly yet common Onion diseases that are ready to sabotage your bumper onion harvest. Fear not! In this action packed blog, we are unmasking notorious onion enemies, revealing their evil plans and sharing Onion Doctors
superhero strategies to save your bulbs. Packed with jaw-dropping Facts& Tips and a call to join forces with us, this guide will transform you into an onion-growing legend. Grab your trowels and let us dig into the battle for Kenya`s finest onions!
COMMON ONION DISEASES IN KENYA AND THEIR MANAGEMENT
1.DOWNEY MILDEW
- Cause: A fungal like oomycete that thrives in Kenya`s cool wet seasons
- Symptoms: Pale green to Yellow spots: Small, pale green or yellowish patches appear on the upper surface of the leaves and stalks
- Impact: Downey Mildew hijacks photosynthesis, slashing bulb size and threatening fields

2.PURPLE BLOTCH
- Cause: A fungus that loves Kenya`s warm, humid lowlands.
- Symptoms: Small, water-soaked spots evolve into purple or brown bullseyes,
- Impact: Purple blotch starves onions by trashing their leaves, cutting yield and inviting rot

3.ONION RUST
- Causes: A relentless fungus that thrives in cool, humid conditions and attacks the Onion family.
- Symptoms: Bright Orange or Dark Brown bumps along the leaf vein
- Impact: Severe infections stunt plants, shrink bulbs and slash yields, leaving onions too small for markets.

4.LEAF BLIGHT
- Cause: Botrytis squamosa pathogen for cool regions and Stemphylium vesicarium
pathogen for warm and humid regions - Symptoms: small, oval white or tan lesions on the leaves, often surrounded by greenish halos. As the disease progresses, these lesions enlarge, become sunken and straw-colored, leading to leaf dieback and eventual death.
- Impact: Can lead to significant yield losses—often ranging from 30% to 60%—by causing premature leaf death, reducing bulb size and quality, and compromising storage life.

5.FUSARIUM BASAL ROT
- Cause: Caused by the soil-borne fungus Fusarium oxysporum f. sp. cepae.
- Symptoms: Initially presents as yellowing and dieback of leaf tips, progressing downward. Below ground, roots may rot and be replaced by white moldy growth, while bulbs exhibit brown, watery decay starting at the basal plate and spreading upward.
- Impact: Field losses can reach up to 50%, while storage losses may range from 30% to 40%, depending on environmental conditions and management practices. In severe cases, infection rates as high as 90% have been reported, resulting in enormous economic losses.

MANAGEMENT OF ONION DISEASES
. Cultural Practices
- Crop Rotation: Rotate onions with non-Allium crops every 3–4 years to break disease cycles.
- Sanitation: Remove and bury infected plant debris to reduce pathogen sources.
- Proper Irrigation: Use drip irrigation systems from Onion Doctor Limited
- Weed Control: Regularly remove weeds that can harbor pests and disease
- Planting Practices:
- Use disease-free seeds and certified planting materials from Onion Doctor Limited
- Avoid planting onions in fields previously affected by diseases for at least 3–4 years
3. Chemical Control
Fungicide Application
- Apply fungicides judiciously, following recommended schedules and dosages.
- Rotate fungicides with different modes of action to prevent resistance
Week | Pesticide | Fungicides | Foliar | Fertilizer |
Land Preparation | Decomposed Manure | |||
1 | Active ingredient | Active ingredient | First Top dressing | |
2 | Mancozeb | |||
3 | Profenofos | |||
4 | Acephale | Carbendazim |
Pro-Tip: Watering with drip irrigations and check plants weekly-it`s like giving your onions a superhero shield! Call Onion Doctor Limited @+254703982228 to set up drip systems and scouting for a super harvest!
Team Up with Onion Doctor Limited!
Diseases bugging your onions or want to grow Kenya`s best Onions? Onion Doctor Limited is your hero! From Onion seedlings, Garlic seedlings, Farm planning services, Soil testing, Drip irrigation installation and maintenance, Agronomic support, Onion and Garlic value pack and Farm management. For free consultation, placing orders or booking a visit with an agronomist
- Call or WhatsApp: +254703982228
- Email:Info@oniondoctor.co.ke.
- Visit:www.oniondoctor.co.ke