Plantwise Factsheets for Farmers
Uproot maize plants with lethal necrosis disease
Maize lethal necrosis disease, ,
Recognize the problem
Maize lethal necrosis disease (MLND) is a
deadly disease of maize. It is caused by two types of viruses which together
kill the plant. At early stages, MLND causes many long yellow stripes on leaves.
This resembles maize streak virus disease but MLND stripes are wider. Later,
the plant leaf edges become entirely yellow, and dry out from the edges towards
the midrib. This is called necrosis. Another disease, Angular Leaf Spot
Disease, can cause drying but only in small patches across a leaf. MLND can
also cause dwarfing and premature aging of the plants. Finally,
the entire plant dries out and dies. Dead plants can then be seen scattered
across the field among healthy looking plants. Late infection of
plants can cause failed tassel development and poor grain filling of cobs.
disease is very severe during the dry season when there is little water in
the soil. Sufficient rain can reduce the problem slightly so it is important
to plant maize during the long rains and to avoid the short rain period by
planting other crops. Uprooting and burning of diseased plants is needed to
get rid of the source of the disease in the field. The viruses are not found in the soil. Aphids,
thrips and planthoppers carry the viruses from one plant to another. There
are no resistant varieties against this disease yet in East Africa.
Maize lethal necrosis disease (MLND) is a co-infection with Maize Chlorotic Mottle Virus and either Sugarcane Mosaic Virus, Wheat Streak Mosaic Virus or Maize Dwarf Mosaic Virus
Scout the maize field once
a week at all stages of maize growth to observe symptoms of the disease as
early as possible
- Uproot all of the plants
that show symptoms of the disease quickly so that the disease cannot be spread.
Do not hesitate to uproot, because the diseased plants will have no yield
- Collect all the uprooted
plants without soil and carefully move all of them to the edge of the farm
into the sun so that they quickly dry and the disease dies. Burning the uprooted plants is also
- Effectiveness of this
method increases when used together with sprays against aphids, thrips, and
planthoppers that spread the disease. WHO toxicity class I products and
Tanzania-red-label-products are not advised.
WHO class II and Tanzania-yellow-label-products are not advised in
Tanzanian IPM schemes. WHO class III or U and Tanzania-green-label or
blue-label-products are preferred. Always double-check with recent list of registered
pesticides (MAFC / TPRI).
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
The recommendations in this factsheet are relevant to:
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