Maize Lethal Necrosis Disease (MLND) in

Kenya

Incidence and Impacts

WOR KS H OP ON “M LN D I AGN OSTI CS A N D M A N AGEM ENT I N A F R I CA”

Intercontinental Hotel, Nairobi - May 12-14, 2015

DR. ANNE WANGAI

CONTENTS

Introduction

Some preliminary observations

Way forward

Introduction: Disease Outbreak

Farmers in Bomet called it, ‘Koroito’

Vernacular name for ‘ a plague’ A sudden phenomenon that could not be

explained, unknown causes, Resulting in a devastating effect to the community.

…..Introduction - Genesis of the Disease

September 2011, disease first reported in the lower parts of Longisa division of Bomet District.

February 2012, noted in Bomet Central division, spreading into neighbouring Chepalungu District, Narok North & South Districts, Naivasha

July 2012, Disease confirmed in most areas in South Rift, Central, Eastern and North Rift regions

All commercial maize varieties including farmers’ local varieties in these regions were susceptible

Yield loss ranged between 30-100%

MLN Predicted Hot spots in Africa (ASARECA, 2014)

Country Year Reference

Peru 1973 Castillo and Hebertt (1974)

USA 1976 Niblett and Cafflin (1976)

Argentina 1982 Teyssandier et al. (1982)

Mexico 1987 Delgadillo and Gaytan (1987)

Brazil 1983 Cited in Uyemoto (1983)

Thailand 1983 Cited in Uyemoto (1983)

China 2011 Xie et al. (2011)

Kenya 2012 Wangai et al. (2012

Tanzania 2012 CIMMYT TF Rept to Ministry of Agriculture, Tanzania

Uganda 2012 G. Asea, Workshop (Nairobi; Feb 12-13, 2013)

Rwanda 2013 C. Ngabiyasonga, MLN Training Workshop (Nairobi; 2013)

DRC 2014 Kumar , FAO Regional Meeting, Nairobi, 2014

Ethiopia 2014 CIMMYT T-Force Rept to Ministry of Agriculture, Ethiopia

Where next ?

…..Introduction: Trend of global occurrence of MLND (CLND)

…..Introduction: Perceived impact of MLND Food Security

Farm income

Food shortage

Period to receive effective, affordable and sustainable control measures

Difficulty of shifting from their dietary preference of maize

=======================

Seed production

Trade implication

Regional/International threat

Some preliminary observations

POST HARVEST ISSUES:

Deterioration of grain Quality

(2014)

45%

1%0%

54%

MERU

67%

0%

4%

29%

MURANGA

72%0%

0%

28%

KIAMBU

MCMV

SCMV

BOTH

NONE

CENTRAL

38%

2%31%

29%

NAKURURIFT

40%

12%

43%

5%

BARINGO

46%

1%19%

34%

Bomet

MCMV

SCMV

BOTH

NONE

0

10

20

30

40

50

60

70

80

% YIELD LOSS DUE TO MLND -2014

% YIELD LOSS DUE TO

MLND

Next Generation sequencing ( Mwathi et al. 2015 )

Viruses identified so far:

Identified Virus Acronym

Sugarcane Mosaic virus SCMV

Maize Chlorotic Mottle virus MCMV

Maize Streak Virus MSV

Maize Dwarf mosaic virus MDMV

Barley yellow dwarf virus BYDV (Luteovirus)

What else ??????

MCMV transmission (Nyvall 1999)

•Mechanical• Insects

Corn thrips Corn flea beetleCereal leaf beetle Corn rootworm

• Seed transmission rates – very low

–MCMV = 17/42,000 plants (0.04%)

–MDMV(SCMV) = 21/72,897 plants (0.03%)

Effect of agronomic practices on disease spread and severity (Amata et al. 2015)

Data on MLND incidences, severities and yield collected in Naivasha, Bomet and Narok counties from trials on effect of

fertilizers,

spacing

rouging and

intercropping.

Treatments did not affect the incidences and severities of MLN.

Intercropping maize with either beans or pyrethrum did not affect incidences and severities of MLN

Role of plant debris and soil in survival and spread of viruses causing MLND (Odula et al. 2015)

Percentages of MLND infected plants noted:

0

10

20

30

40

50

60

70

80

Leaves Stem Roots Infected soil whole plant Sterie soil

%infection

%infection

Other pathogens & nematodes associated with MLND causing virus (Kinyua et al.2015)

Fungi commonly isolated were:

Fusarium sp.,

Phyllachora maydis,

Penicillium sp.,

Diplodia sp. &

Colletotrichum sp.

Nematodes commonly

extracted were:

Helicotylenchus,

Rotylenchulus,

Pratylenchus,

Meloidogyne,

Hoplolaimus &

Tylenchus

Susceptible Susceptible

/resistant

Resistant

Zea mays Triticum sppHordeum vulgare L.

Eleusine coracana

Sorghum bicolor

Oryza sativa

Pennisetum purpureum

Chloris gayana

Pennisetum cladestinum

Cynodon dactylon

Cyperus rotundus

Chloris rexburghiana

Enteropogon macrostachyus

Eragrostis superb

Cenchrus ciliaris

Host range (MCMV)

(Odula et al.2015)

Vectors of viruses causing MLND, their host range

and management options (Nyasani , Kasina et al. 2015)

Competences of 5 potential vectors for transmitting either

MCMV or SCMV have been determined

Three (3) potential vectors of MCMV have been identified.

One (1) potential vectors of SCMV has been identified.

Six (6) host plants of MCMV/SCMV have been identified.

Three (3) natural enemies of thrips have been identified.

Distriburion maps of potential vectors of viruses

causing MLND

Beetles Aphids

LeafhoppersStemborersThrips

Spatial distribution of

potential vectors of

Maize chlorotic mottle

virus and Sugarcane

mosaic virus in Kenya

(Nyasani et al. 2015)

Evaluation of pesticide control options for MLND (Kinyua , Kasina ,Ngaruiya et al. 2015).

Trial involving 8 foliar products:

Carbosulfan,

Acephate,

Thiocyclam,

Chloropyrifos,

Imidachloprid,

Acetamiprid,

dimethoate and

thiamethoxam

Seed treatment pesticide

technologies for the control of

MLND. 3 seed treatment products

carbosulfan,

thiamethoxam and

clothianidin).

Way forward:

SCMV and MCMV were prevalent: Variability and distribution need to be established

MCMV is THE major virus of concern: Other viruses/factors involved in MLN expression to be identified.

Seed transmission is playing an important role in spreading MCMV: Seed transmission and contamination to be eliminated

Soil and plant debris play a role in retaining virus: Farm practices to be identified to prevent re-introduction and sustaining of MCMV

Longterm solution: Resistant germplasm deployed

Acknowledgement

Acknowledgement

Director General, KALRO

KAPAP

MLND Collaboration Team

MoAL&F

CIMMYT

AGRA