Bioversity International scientist Devra Jarvis presents work carried out in China, Ecuador, Morocco and Uganda on using crop varietal diversity to manage pests and diseases. The presentation highlights how when grown in crop varietal mixtures, pest and disease damage can be reduced. Find out more: https://www.bioversityinternational.org/research-portfolio/agricultural-ecosystems/pests-and-diseases/

1. Improving productivity and resilience for the
rural poor through enhanced use of crop varietal
diversity in integrated production and pest
management (IPPM)
Devra Jarvis, Analyzing Diversity, Damage, and Yield data from Crop
Varietal Mixtures, 20-24 April 2015 Italy

2. Vulnerability in agriculture: increased
probability of future crop loss
Large areas planted to monocultures of
leading cultivars (high genetic uniformity)
Productivity
Vulnerability

3. Remember the wide-scale famine caused by the 1840
Irish potato blight?
• Sugarcane rust attack in Cuba (losses up to 500 million USD)
• Rice blast epidemics in Korea - 30-40% yield losses.
• Black sigatoka in Central American countries loosing nearly 47% of their
banana yield

4. Earlier actions
Resistance Breeding
Modern varieties, are frequently overcome by new races
of pathogens and pests in only a few cropping seasons.
Pesticides
Harmful impact on human and environmental health
Very limited use of the opportunities offered by effective
management of intra-specific diversity (local crop varieties)
within the agricultural ecosystem in IPPM strategies.
Integrated Pest Management (IPM)
• Agronomic management techniques to modify the environment
around modern cultivars and reduce the need for pesticides.

5. Crops: food security of small farmers;
different breeding systems
• Coverage of different resistance gene system (where resistance is
controlled by both major and minor genes)
• Transmission systems: seed-borne, soil-borne, and air-borne
• Plant organ affected: leaf, stem, seeds and roots
Host - pest/disease systems (known variation in resistance)

6. Genetic Diversity
(Y)
Low
Productivity
(yield,quality,culturalgains)
(Z)
Site A
High X
Low Y
High Z
Site B
Low X
High Y
High Z
High Z
High X
High Y
AHD Brown, 2012
This is the axis we
can maneuver
Including crop varietal diversity in pest and
disease management strategiesProductivity
Vulnerability

7. Reduce crop loss from pest and disease damage
Varietal mixtures, improved resistance in local varieties, improved
productivity of resistant traditional varieties, improved genetic
diversity management
(2) Reduce vulnerability – reduce the probability of crop loss in the
future
Increased number of different landraces with different resistance available to
farmers
(3) Provide alternatives to pesticides
Monitoring the impact of adding in the element
of crop varietal diversity into IPPM strategies:

8. Component 1: Practices and Procedures to determine
and optimally use crop genetic diversity to reduce pest
and disease pressures
 Identify and compile farmer knowledge and practices
 Conduct experiments using intra-specific diversity

9. Determining when and where intra-specific diversity
is the answer (or not) – FGD, HH, Field Lab trials
Step 1. Are pests and diseases a problem?
Step 2. Does variation for resistance among and within traditional crop varieties exist for
the target disease
Step 3. Does this variation reduce disease and pest damage and vulnerability in the field
Step 4. Is there variation in the population structure of pests and pathogens over time and
space (are we are dealing with a variable pathogen or pest species, and the
nature of the variation)
Step 5. Is crop varietal diversity accessible to farmers?
Step 6. How are seed systems affecting pests and diseases movement?
Step 7. What “genetic choices” do farmers make to minimize crop loss?

10. Crop varietal diversity assessment on farm –
the problem of variety names and
distinctiveness
Diversity fairs
Focus group discussions
Individual interviews

11. Research protocol (involves farmers and scientists)
Identifying pest and disease and host resistance
Pest/disease description
Plant part affected and stage affected
Disaggregated data by gender,
age, social groups
Varieties
Pests and diseases
Scoring resistance of varieties to pests and diseases

12. Varietal diversity in field resistance to black sigatoka
Variety diversity to nematode damage
Lower number of functional leaves = more disease
Functional leaves
Agama, Vera, Vaca, Cabanilla, and Suarez, 2011

13. The concepts of richness and evenness
Richness = 9 (local varieties): A=B
Evenness (less dominance): A>B
Farm A Farm B
Areaplanted
Different varieties (v)
V1
V2
V3
V4

14. left right
Infront
SPOT 3
left right
Infront
left right
Infront
left right
Infront
left right
Infront
SPOT 5
SPOT 1
SPOT 6
SPOT 2
left right
Infront
SPOT 4
GPS
Reading
Local mixture of 3 barley
landraces (Shangrila)

15. Weevils
ALS Anthracnose
Richness Richness
Simpson (evenness) Simpson (evenness)

16. Richness VS Percentage Disease Panicle for Rice Blast
Wu Shuo, Yang Xue Hui, Peng Huaxian, Wang Yunyue, 2012

17. Measuring vulnerability reduction – or the
probability of future crop loss
F-test says that the
disease variance
decrease with the
increase of richness
Maize from Sichuan: Richness vs Damage

18. Any relationship between agro-morphological traits diversity
and disease incidence for traditional and modern varieties?
Peng et al in progress
On farm maize experiment,
planted in Zhaojue,
Sichuan Province, China
(2009)
Sichuan
traditional
varieties
Yunnan
traditional
varieties
Modern Varieties
Principal Component Analysis (PCA) on agro-morphological traits

19. Damage variance: modern vs traditional varieties
(Zhaojue 2009 experimental trials)
● 3 groups of variety
● 2 different groups of landraces
● Different level of disease
incidence among the three
groups
Peng et al in progress

20. Photo: Joyce Adokorach
Can increasing the level of diversity in a field, in a
controlled selected repeatable way, with well chosen
components, give a benefit over monocultures, or
over treatments with less diversity?

21. Musa spp. (banana, plantain) mixture trials -
Uganda
Population growth in this field was observed to be
very low compared to expected increase of 1000
adult weevils per year
Mulmba et al., unpublished data
Weevildensityperhectare

22. Component 2: Enhanced Pro-Poor Capacity and
Leadership of farmers and other stakeholders to use local
crop genetic diversity to manage pests and diseases

23. ECUADOR: Improving farmers knowledge
Farmer meetings: children (schools) and adult (promoters)
Training manuals: basic aspects of pest biology and diseases
management, basic aspects of crop diversity

24. China
Conserved total 38 local rice
varieties,73.68% is upland rice and 9 local
maize varieties from Menghai county in
Xiding community seedbank.
Posters also
were put on the
wall of the
government and
hospital

25. Morocco - Materials

26. UGANDA: Capacity building/ awareness raising activities
Participatory Research with farmers
including:
Trials establishment
Monitoring Data collection

27. Scaling up and benefit sharing
(i) Damage Abatement Framework
Daniela Horna et al.
Replicating and Adapting good practices

28. Achieving project outcomes
(2) Increased quality diverse
varieties to farmers
(1) Crop losses reduced
(3) Portfolio of diverse rich practices

29. Crop losses reduced by 10% from reduced pest
and disease damage for at least 20% of the farms
in project sites
1. FDG, HH survey with On-farm observations show increased diversity of crop
varieties distribution across farmers’ fields corresponded to a decrease in
average crop damage levels and reduced risk to future damage
2. Cross-site, on-farm experiments identified traditional varieties with more
effective resistance to pests and diseases when grown outside their home sites
3. Increased production (yield and/or less crop loss) from clean diverse sets of
seeds provided from community seed banks, seed fairs, and other project for
small holder farmers in the sites (% or amount yield increase; % or amount of
decrease in crop loss)
4. Intra-specific (variety) mixtures with non-uniform resistance tested in all
countries and specific cases where mixtures out-performed their component
monocultures in reducing crop damage and increasing yields identified for
further testing

30. Increased number of different landraces with
different resistance available to farmers (amount
of seed; number of varieties; number of farmers
reached)
Measured by:
• Change in the amount of diversity (number/richness; and
evenness) in farmers’ field; Change in type: agromorphological
types, molecular characteristics
• From community genebank (number of varieties accessed each
year, amount of seeds accesses. Characterization of the
materials.
• Change in local seed suppliers in supplying traditional varieties or
enhanced local varieties – number of seeds supplied (quantity of
seeds, number of varieties, number of people distributed too).

31. A portfolio of diversity-rich practices provide
alternatives to pesticide use to minimize crop
damage in project sites
1. Examples of linking good agronomic practices with intra-specific
crop diversity to management pest and diseases to improve
production
2. Examples of locally identified resistant materials integrated into
national resistance breeding procedures with farmer selection
criteria
3. Progress in developing or using a damage abatement
methodology and/or choice experiments developed to determine
economic trade-offs using crop genetic diversity versus other
IPM, resistant breed varieties or chemical input methods

32. Acknowledgements: Participating farmers, local, national and international institutes,
organisations and partners, IFAD, SDC, DGIS, FAO, UNEP/GEF, and Ford Foundation.
Global cooperation: National partners lead the way!!!
http://agrobiodiversityplatform.org/cropbiodiversity/

33. www.bioversityinternational.org
Thank you
Devra Jarvis, Principal Scientist
d.jarvis@cgiar.org