This archive report was first published on 14 December 2019.
Heavy rains in Kenya have left onion farmers in a state of despair as their crops succumb to downy mildew, a fungal disease that thrives in humid conditions.
According to experts, the disease is most common during the rainy season, and its spread can be accelerated by overcrowding and poor drainage.
Ngatia, an onion farmer in Nyandarua County, recently experienced the devastating effects of downy mildew firsthand. His crop was severely affected, with leaves drying up and bulbs remaining tiny.
Downy mildew is characterized by the growth of a white and later purplish mould on the leaves, which can lead to reduced yields and spongy bulbs.
Experts recommend observing proper spacing of 8cm inter-row and 10cm intercrop during planting, as well as ensuring good drainage by raising beds and creating drainage channels.
Additionally, farmers are advised to avoid overhead watering in humid conditions, practice timely weeding, and remove affected bulbs to prevent the fungus from spreading.
Other diseases that affect onions during rainy seasons include purple blotch, caused by the fungus Alternaria porri, which manifests as small, water-soaked lesions on the leaves.
By following best management practices, such as starting with disease-free seedlings and avoiding excess nitrogen application, farmers can minimize the occurrence of these diseases and ensure a healthy crop.
