incidence and impact of maize lethal necrosis disease in tanzania
TRANSCRIPT
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Incidence and Impact of Maize Lethal
Necrosis Disease in Tanzania
Presented to Regional Workshop on MLN Diagnostic and Management in Africa Held at Intercontinental Hotel
Nairobi - Kenya
12th - 14th May 2015
By
Kitenge, Yangole, Makoye,
Mbwana & Inviolata
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Outline
Introduction
Disease identification survey
Survey report
Measures taken
Immediate
Long term
Way forward
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1. Introduction
In 2012, farmers reported of unknown disease affecting maize in some areas of
Lake zone (Mwanza, Musoma and Shinyanga)
Central zone (Singida)
Northern zone - (Manyara- Babati, Mbulu and Simanjiro)
(Arusha- Karatu, longijave, Mlangarini and Arusha)
(Kilimanjaro – Moshi Mwanga
Therefore there was a need of conducting a disease identification survey
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Maize lethal necrosis infestation in northern part of
Tanzania
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Maize lethal necrosis infestation in lake zone part of Tanzania
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2. Disease identification survey
Following reports of an unknown disease in Tanzania,CIMMYT was invited to become part of a task force toconfirm reports of a new maize disease that has beenspreading and causing major loses among farmers
The Task force was comprised of Drs. George Mahuku(Pathologist),and Dan Makumbi (Maize Breeder) ofCIMMYT, and Dr AnneWangai from Kenya AgriculturalResearch Institute.
The team was hosted by Mr. Ignath Rwiza from theLake Zone
Agricultural Research Institute (LZARI) in Mwanza, and
late Dr. Richard Ndondi from Suba-Agro Trading
Company (SATEC) in Arusha.
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In about 4-day period, the team managed to visited 8 farmsin the Mwanza region and 4 farms in the Arusha region.
A total of 60 samples (30 from Arusha region and 30 from Mwanza region) were collected and these were analyzed for thepresence of the potyvirus- sugarcan mosaic virus (SCMV)
Out the 30 samples from Mwanza region, so far 9have beenanalyzed and 4 samples tested positive for MCMV
Some of the samples were analyzed using reverse
ranscriptase polymerase chain reaction Rt-PCRtechnique with potyvirus-specific primers
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…Survey report
All samples from the Arusha region have been tested, and
2 samples were positive for MCMV, 8 samples for SCMV and
14 samples were positive for both MCMV and SCMV.
No virus was detected in samples collected from a very
young crop labeled field 13 in Arumeru district. Maize lethal
necrosis disease (MLND) or Corn lethal necrosis (CLN) is a
result of infection of maize plants by SCMV and MCMV.
The detection of both viruses, either alone or in combination
in the samples collected confirmed the presence of MLND in
Tanzania
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…Survey report
Affected plants Affected plants
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Karatu April, 2013 Nshara – Hai, April 2013
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Disease Symptoms
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Disease Symptoms in cont’d
Mlangalini - Arusha Mlangalini - Arusha
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Measures taken
Immediate actions
Sensitization activities
Information sharing with stakeholders (emails, reports)
Training extension, politicians and other decision makers at
district , region and national levels though their respective
meetings
Interviews to researchers made by journalists and Press releases
Present papers to policy makers within & outside the zone -
Parliament
Through conducted field visits to districts in the zone
Production & distribution of extension materials (brochure,
posters)
Video documentation
Still pictures collections
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Participants from Rombo, March 12, 2013
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Participants from Same and Siha DCs,
March 15, 2013
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Participants from Arusha and Mbulu DCs, April 23, 2013
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Participants from Babati TC, May 3, 2013
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Effort to combat the disease
Writing a proposal involving multidisciplinary
activities to contain the disease
Breeders
Agronomists
Pathologists
Extensionists
Social economists
Police makers
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National efforts
Tested available material for resistant
Testing for new developed materials (for SARI, Uyole
and from local seed companies)
Collection of new gerplasm from various places for
screening
Use of chemicals
Seed treatment
Routine plant spraying with systemic insecticide
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Disease transmission
MCMV SCMVThripsAphids and
leafhoppers
Interaction between the two Diseases
MLND
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Several insects implicated as vectors in literature:
Thrips
Aphids
Leaf hoppers
Corn root earworm
Most commonly thrips (Frankliniellawilliamsi) associated with MCMV and aphids with SCMV.
Transmission is non-persistent for both MCMV and SCMV
Spread
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Regional efforts
KARLO –CIMMYT – developed a regional MLN
screening facilities at KARLO Naivasha where we
send our new material for screening
CIMMYT develop, screen, multiply and distribute
elite material among partners for testing
This season we have more than 3000 entries
(inbredlines and testcrosses) for evaluation under
MLN hot spot areas
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Regional efforts con’t…..
ASARECA has significantly contributed to
MLN struggle
Funded a regional (Seven countries) two
year project combating the disease
We assemble new materials to CIMMYT
for screening multiply and distribute
among participating countries for testing
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Solutions (What farmers should do)
Use treated improved seed
Proper field management
Fertilizer application
Field sanitation
Early planting
Rouging if few plants are affected
Distraction of the whole field
Crop rotation
Reporting to their leaders
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2m apart
Maize affected by MLNDAmigo at 1.2mg rate + Thunder
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MLN- INFECTION AT 5-6 WEEK
Seed dressed treatment + Foliar
applied
Untreated treatment
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0
10
20
30
40
50
60
Me
an m
aize
he
alth
pla
nts
an
d c
ob
s
Treatments
Health Plants
Health cobs
The mean maize health plants and cobs harvested per plots at Ngaramtoni
Results
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1. Poncho FS600 at 0.5mg/kernel and Amigo
FS275 at1.0mg /kernel seed treatment
equally adequately protected the crop from
MLND infection via control of the aphids and
Thrips vector ,
but for only about 2 weeks after germination.
This was confirmed from less vector counts and
disease incidence in that period.
Conclusion
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2. Thunder OD 145 foliar spray treatment alone
commencing from the 2nd week after germination was
not very effective in the disease reduction,
although the vector control from that period was
significantly reduced.
This means that the vector had already infected the
plants meaning that this intervention was already too
late for the disease control.
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3. Generally, seed dressing combined with foliar
sprays tested in this study are effective in reducing
MLN incidence at early stages of plant growth.
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Long term &The way forward
Continue collecting new germplasm and screen for
the resistance
Development of new varieties using resistantparental materials
Release of resistant varieties
Maintain restriction of seed movement
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KOBE Mode of Action
Two Distinct Procedures
Inducing Plant Resistance
Mechanisms
Affecting the
Pathogen itself
SAR ISR
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Kobe 1.2SL vs MLND
Traditional MLND management Only by trying to
manage the vectors (Aphids, Thrips ….)
KOBE Faces not the vector but the cause itself
Actually forces the plant to resist the disease
Promotes the plant’s own resistance capacity
Leads to more vigorous & stronger plants
Reduces the yield loss due to the disease
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Kobe 1.2 SL
Rheum officinale Bail
Originating from Asia
Family: Polygonaceae
Common Name:
Rhubarb
In chinese: yào yòng dà
huáng (Chinese: 药用大黄
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Apreciations
Thanks to
Organizers
Donors
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The End