MLN Incidence and Impact in Uganda, presented at the International Conference on “MLN Diagnostics and Management in Africa,” organized by AGRA (Alliance for Green Revolution in Africa) and CIMMYT, 12-14 May, 2015

1. MLN Incidence and Impact in Uganda
Godfrey Asea
Maize Breeder/Programme Leader, Cereals
Presented at the workshop on MLN diagnostics and management in Africa

2. 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

3. 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 confirmation
3

4. Field with MLN symptoms
4

5. Location MCMV SCMV Protein
Sironko + _ +
Kabanyolo + _ +
Busukuma + _ +
Nakyesasa -
Napier
_ _ _
Namulonge-
Napier
_ _ _
DAS-ELISA kit from DSMZ
and protein-A Sandwich
ELISA analysis in Kawanda

6. Spread of MLN in Uganda 2012-2014

7. 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

8. • Several promising pre-
commercial hybrids
under validation
announced by CIMMYT.
• We made seed requests
and PIP for promising
inbred lines and hybrids
received 2013.

9. 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

10. 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

11. 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

12. 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. 13
Training of scientists and technicians