Maize is a crucial food crop in Kenyan households accounting for nearly half of the calories and proteins consumed. The occurrence of the Maize Lethal Necrosis Disease (MLND) is a major concern since the disease threatens food security for the majority of households in the country.
This disease was first reported in Kenya in 2011, specifically in Bomet County. Within no time, it had spread to other countries including Nakuru, Narok, and later other countries in East and Central Africa.
What Causes Maize Lethal Necrosis Disease?
MLND occurs when there is a simultaneous infection in maize, by Maize Chlorotic Mottle Virus (MCMV) together with another cereal-infecting virus. It could be Sugarcane Mosaic Virus, Wheat Streak Mosaic Virus, or Maize Dwarf Mosaic Virus. A co-infection of the MCMV with any of the three viruses induces the lethal disease which can cause yield loss of up to 100%.
Once a maize crop is affected, the disease can spread through pests such as maize thrips, leaf hoppers, leaf beetles, and rootworms. It can also spread through farming implements, animals, and planting materials.
How Can You Identify a Crop Infected by MLND?
Here are the symptoms you will observe when your maize has MLND in Kenya:
- Leaves dry from the margin towards the midrib
- Short internodes (leaves develop close to each other along the stem)
- A yellow-green mottled pattern on the leaves
- The entire plant withers in severe infections. Dead hearts (withered or dry leaf whorls/ central leaves) are visible inside the stems
- The plant produces cobs with little or no grains
Managing Maize Lethal Necrosis Disease in Kenya
MLND is a viral disease and thus has no treatment. You should take preventative measures to prevent the spread of the disease. These measures include:
Crop Rotation
Avoid planting maize in the same field continuously to break the disease cycle. Plant non-cereal crops such as onions, garlic, potatoes, and other vegetables for at least two seasons before you grow maize on the same land.
Use Certified Seeds
Do not use grains as seeds. Obtain seeds from certified sources to control vectors.
Ensure Good Nutrition
Nutrient-deficient plants succumb easily to disease infections. Use manure and other fertilizers to boost crop vigor and its defense against MLND.
Weed Control
Maintain weed-clean fields to eliminate plants that may serve as hosts for MLND vectors.
Inspect the Fields Regularly
Scout for either of the following:
Infected Plants
Check for symptoms of MLND. If you find severely infected plants, uproot and burn or bury them in an isolated part of the field. Further, avoid moving infected plants from the affected areas to the non-affected ones.
Disease Vectors
Sticky traps can help identify vectors in the field. Blue sticky traps are used to trap thrips while the yellow ones are used to capture grasshoppers and beetles. If you find vectors, you can use imidacloprid or lambda-cyhalothrin to control maize thrips and leaf hoppers.
There is no treatment for Maize Lethal Necrosis Disease. However, you can implement an integrated pest management approach and keep the disease at bay. A combination of preventative measures including using certified seeds and ensuring a weed-clean farm can help avoid introducing the disease into the farm. But if some plants are already infected, uproot them to avoid further spread.