Joyce Mulila Mitti
Plant Production and Protection Officer
FAO Regional Office for Africa
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Background
◦ Thoughts on invasive plant pests
◦ Drivers of spread of invasive pests
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MNLD History and current knowledge
Disease manifestation
MLND interventions in Kenya
Management Options
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Recognition of the significant losses to
farmers and food security of plant pests and
diseases.
Many are endemic, with periodic upsurges or
outbreaks under favourable conditions.
Of significant economic, trade and/or food
security importance for a considerable
number of countries
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Environmental factors: weather, climate,
wind borne
Pest/disease threats- vector-borne
(pathogens)
Production Practices
Biological events
(Long distance) movement
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Locusts
Fungal diseases (wheat, potato...)
Climate - changes:
◦ cropping range => changing pest ranges
=> changing predator populations
◦ pest population dynamics
◦ susceptibility to disease (vector distribution,
plant susceptibility...)
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Overlapping planting seasons
Expanded areas under a single crop
Perennial culture (e.g. banana)
Presence of alternate wild hosts
Abiotic stresses
Inappropriate use of insecticide
Overuse of inputs such as herbicide
• MLND – Emerging New Disease of Maize in East Africa
• Leaf yellowing, scorching,
necrosis and eventual death
of the affected plant.
• Affected plants decline
rapidly (within days to
weeks).
• Reports suggested rapid
spread within and between
the fields.
Source: CIMMYT
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“Maize farmers in Kericho and Bomet suffer a
loss due to outbreak of a fungal disease”
“Despair as mysterious bug destroys maize
farms”
“Disease threatens Kenya’s maize crop”
“The maize disease that could change Kenya”
“Kenya: 300 Hectares of maize ruined by disease
in Nandi”
“Experts at war as maize growers harvest big
losses”
“Kenyan maize crop failing….and Ministry of
Agric failings”
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MLND is known officially in Kenya since 2011.
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In Tanzania it was reported in late 2012 in
Arusha, Mwanza and Manyara
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In Uganda MLND is reported in Busia and
Tororo districts
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Unconfirmed reports of occurrence in Rwanda
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First reported in Bomet district in South Rift Valley during
the Short rains of 2011
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Initial hotspots appeared in places where mono-crop
maize was grown continuously
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Current status of spread
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30 districts in Rift Valley,
5 districts in Eastern Kenya,
9 districts in Central Kenya,
5 districts in Western Kenya
6 districts in Nyanza
Over 77,000 ha of maize were affected in 2012, translating into an
estimated loss of 1.4 million bags each of 90 kgs worth about Ksh
4.4 billion (USD 52 Million).
Incidence of MLND*
District
90,000 hectares
MLND
affected
districts
Kisii
Narok
Bomet
Ngakinyua
Nakuru
Embu
Meru
Eldoret
Makueni
Machakos
Bungoma
Kakamega
Incidence (%)
90
90
80
80
70
60
60
5
– 100
– 100
– 100
– 100
– 100
– 100
– 100
– 20
Nil
Nil
Nil
Nil
•MLND spread in 90,000 ha
[4.3% of 2.13 million ha devoted
to maize in Kenya]
*Source: Report on MLND, Multidisciplinary
Team Report, Ministry of Agric, Kenya (July
2012)
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Causal agents: Maize chlorotic mottle(MCMV)
& sugarcane mosaic viruses (SCMV)
Cause of disease emergence: not known,
SCMV known to occur in Kenya and many
other countries in Africa; MCMV is new.
The extent of spread is evidence that the
disease has been present for sometime (such
infection unlikely in 1 to 2 seasons).
Vector control and resistant varieties
◦ No resistance to MLND
◦ But resistance to SCMV or MCMV prevents MNLD
Sugarcane mosaic virus
Potyvirus
Potyvirus (source: ICRISAT)
Aphids
Source:INERA
Source: CIMMYT
Maize chlorotic mottle virus
Tombusvirus
Tombusvirus (Source L. Kumar)
Thrips
RA Naidu
Source: University of Hawaii
Maize lethal necrosis disease (MLND)
Sum of all
RA Naidu
Potyvirus (source: ICRISAT)
©Edwin Cheserek
Source: CIMMYT
Source: University of Hawaii
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Leaf yellowing, scorching, necrosis and eventual
death of the affected plant.
Affected plants decline rapidly (within days to weeks)
Reports suggest rapid spread within and between
fields.
Symptoms appear at different stages of plant growth;
no uniform pattern of disease development
suggesting external factor in transmission; e.g. insect
vector transmission.
Debates on the causes: fungal disease, poor seeds,
varietal, agronomic practices etc; whether to burn
damaged crop and whether to feed to animals
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MLND Task Force formed- KARI, MOA, PPSD,
KEPHIS, ICIPE, FAO, KAPAP
Resource Mobilization: proposal developed for
comprehensive management of MLND submitted
to the World Bank
On-going research: extensive varietal screening
of germplasm of over 2000 materials in 4
locations including Niavasha and Bomet.
◦ Screening done both under natural and artificial
situations (use of inoculum)
◦ Few lines showing tolerance- need for further testing in
multi-locations
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Screening of different pesticides for control of
vectors; 19 pesticide formulations being
evaluated at Naivasha and Bomet on 1 variety by
PCPB
◦ Seed dressing with fungicide in addition to spraying, the
crop fairs better
◦ Spraying without seed dressing; crop performs poorly
◦ All pesticides effective at killing thrips, but new thrips
populations develop fast requiring several sprays
◦ Thrips hide in leaf funnels so difficult to completely kill
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Training of staff from KARI and KEPHIS on seed
testing; capacity to determine whether disease is
seed borne.
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Regional workshop convened by KARI/CIMMYT
◦ Confirmed Regional presence of disease;
◦ Concern at low level of resistance
◦ Recommended establishment of a centralized regional screening facility in
Kenya for Central, Eastern and Southern Africa
◦ Agreed on urgent need to address genetic architecture of MLND, seed
transmission, alternative hosts, host-vector interactions and management
◦ Need to initiative seed production and delivery mechanisms for the disease
tolerant lines
◦ Support for continuous MLND surveillance
◦ Socio-economic studies on impact of the disease
◦ Awareness creation to involve and target farmers proactively
◦ Agreement that disease control should be regional; KARI and CIMMYT to
develop a C/N.
Awareness creation: FAO has provided support to
the MOA to develop a manual for TOT on MLND.
◦ Brochures and posters, radio programmes on MLND also
developed.
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Phytosanitiation (elimination of infected plants) –
feasible if disease is detected early, however, large
scale implementation is difficult
Crop rotation – break in cropping cycle can reduce
the disease persistence and spread
Vector control – pesticides to control insects can be
effective both as mitigation and pre-emptive
option. However, expensive and not eco-friendly.
Host resistance – Some few MLND resistant sources
have been identified, can offer best protection
against the diseases
Thank you all for
your attention!