MLN Incidence and Impact in Uganda

Godfrey Asea

Maize Breeder/Programme Leader, Cereals

Presented at the workshop on MLN diagnostics and management in Africa

MLN status in Uganda

● First reported in October 2012 in

farmers’ in Busia and Tororo

districts

● Isolated cases of typical

symptoms of MLN were observed

● Since spread to more than 18

districts within 2 years

● Severely infected crop – late

planted crops

MLN status in 2013 and 2014

• Season characterized by

prolonged drought in 2013 and

good rains in 2014 in maize

growing areas

• Disease incidences greater than

30% observed in infected fields

• Samples collected from plants

showing typical symptoms and

sent for confirmation3

Field with MLN symptoms

4

Location MCMV SCMV Protein

Sironko + _ +

Kabanyolo + _ +

Busukuma + _ +

Nakyesasa -

Napier_ _ _

Namulonge-

Napier

_ _ _

DAS-ELISA kit from DSMZ

and protein-A Sandwich

ELISA analysis in Kawanda

Spread of MLN in Uganda 2012-2014

New Sources of MLN resistant/tolerant inbred lines

16 MLN tolerant/resistant lines from CIMMYT in 2013

10 MLN resistant lines from OSU in 2013

28 MLN resistant lines from Hawaii

• Several promising pre-

commercial hybrids

under validation

announced by CIMMYT.

• We made seed requests

and PIP for promising

inbred lines and hybrids

received 2013.

Status of MLN tolerant hybrids in NPTs

Hybrid 2014 Naivasha

MLN score

Status Remarks

CKIR11010 3.2 NPT1

CKH10773 3.2 DUS, NPT3 submitted

CHMLND0086 2.3 DUS, NPT3 submitted

CKH12603 2.8 DUS, NPT3

CKH10769 2.8 DUS Released

CKH12602 3.2 NPT1

CKDHH0744 3.2 Experimental

CKDHH0207 3.2 Experimental

Com. Check 3.7

Breeding efforts for MLN resistance

● Making new testers with low MLN scores

● MLN resistant pedigree starts, advancement and formation

of resistant/tolerant products

● Introgression of MLN resistance to local adapted

germplasm

● Evaluation of and seed production of promising MLN

tolerant hybrids

● Established two MLN germplasm screening sites under

natural conditions for virus strain/tolerance validation

● Building diagnostic capacity to identify by PCR using

primers for MCMV and SCMV and ELISA

Seed Production Considerations

● Use wide rotations with non-host crops

● Intensive insect control measures for thrips and

aphids :–

● Possible options: seed treatments (Imidacloprid,

Fipronil, Thiamethoxam, Gaucha) and frequent

spray regimes (endosulfan, dimethoate,

Imidacloprid, Thiamethoxam, synthetic pyrethroids)

● Spray 20 m grass borders of seed fields

● Rogue & remove from field diseased plants early

● Extra isolation distance from other maize fields

Phytosanitary measures and regulation

● Continuous field surveys and surveillance through the

SOP being implemented

● Stronger interface among all relevant institutions,

including regulatory authorities, research, extension

system, seed industry, seed/grain importers and

exporters, and policy makers

● Local quarantine imposed

● Analysis of economic and social impact of MLN-

copping strategies, economic loss

● Identifying MLN knowledge and information needs

and opportunities

13

Training of scientists and technicians