The document summarizes the push-pull system, an integrated pest management approach developed to control stemborers and parasitic striga weed in cereal crops like maize. It works by intercropping a repellent plant and an attractive trap crop. Napier grass is used as the trap crop for stemborers, while silverleaf desmodium acts as the repellent plant that also suppresses striga. The system provides benefits like increased yields, fodder for livestock, soil health improvements, and adaptation to climate change. Recent research also found it effectively reduces ear rot and mycotoxin infections in grains. Over 122,500 smallholder farmers in sub-Saharan Africa have adopted push-pull, more than

1. Improving Food Safety by Reducing Aflatoxin
Infection in Cereal Crops grown under Push-Pull
System (www.push-pull.net)

2. What is Push-Pull System?
The ‘Push-Pull’ system is a
novel approach in pest
management, developed by
understanding the complex
mechanisms that govern the
ecology of plants and insects,
which uses a repellent
intercrop and an attractive
trap plant. Insect pests are
repelled from the food crop
and are simultaneously
attracted to a trap crop.

3. Crop loss by cereal stemborers
Total Maize Area in SSA 25,375,000 ha
Estimated loss due to stemborers 15%
Value of Maize in SSA US$ 10b
Maize lost due to stemborers US$ 1.5b

4. crop loss by parasitic striga weed
Total Maize Area in SSA 25,375,000 ha
Total Maize Area with Striga 6,122,000 ha
% SSA Area infested with Striga 25%
Value of Maize in SSA US$ 10 b
Value of Maize lost due to Striga US$ 2.5 b

5. Pull
Napier grass is a perennial
fodder grass of African origin and
of economic importance for
livestock farmers.
Many cultivars of Napier grass
were found to be highly preferred
for stemborer oviposition as
compared to maize. However,
Napier grass does not allow
development of stemborer larvae
to their adulthood and can be
used as a trap plant.
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
Days after egg hatch
%Larvalsurvival
Ex-Nyanza-1
Clone 13
Bana
Ex-Machakos
Ex-Nyanza-2
French Cameroon
Gold Coast
Mott
Pakistan Hybrid
Uganda Hairless
Maize

6. Push
During attempts to control
stemborer damage to maize by
intercropping with repellent
plants, fodder legume silverleaf,
Desmodium uncinatum, was
accidentally found to reduce
incidence of infestation by the
African witchweed, Striga
hermonthica. This reduction was
confirmed and shown to be
significantly greater than that
observed with other legumes.

7. How Desmodim Controls Striga
Retention time
Region of Striga post-germination inhibitors
Region of Striga germination stimulants
Analytical HPLC (C-4 reverse column) profile of the acetone extract of D.
uncinatum roots

8. Adaptation of push-pull system to Climate Change
The push-pull system is now fully adapted to the increasingly dry and
hot conditions associated with climate change in Africa to ensure its
long term sustainability. As the conventional push-pull system had not
been extended to drier areas of sub-Saharan Africa, the new research
has provided a relevant and effective agricultural innovation for
cereal-livestock smallholders living in those areas.

9. Stem borer and Striga Control and yield increase
After
Before After

10. Fodder Availability and Milk Production
Both trap and repellent plants used in
the ‘push-pull’ strategy are of economic
importance to farmers as livestock
fodder and help increase milk
production.

11. Push-pull improves soil health
Total soil carbon
Treatment
PP Mono PP-1998 Mono
TotalsoilC(%)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Monoculture
Push Pull
Total soil N and plant available P were
significantly greater in soils under push-pull
intercropping (dark green) than in maize
monoculture (light green)
Desmodium improves N, P and C in the
soil and has a trailing habit, helping
conserve soil moisture. It reduces
digging and adds to soil organic matter,
enhancing the capacity of the soil to
sequester carbon. It has a positive
effect on plant and insect biodiversity,
and has been shown to result in soil
that is rich in beneficial micro-organisms

12. Gender in push-pull technology uptake
Climate-smart push-pull adopters
More than 122,500 farmers (>60% female) have adopted push-pull, out of which > 54,000
adopted its climate-adapted version. The rate of adoption of the climate-smart push-pull by
female farmers is growing faster than that of male farmers (inset) because the technology’s
labor saving advantages. The Brachiaria grass used in the climate-smart push-pull is easier to
manage by women than Napier grass used in the conventional push-pull
The technology is gender
friendly and saves women
and disabled famers from
drudgery, and ensures
better food security,
nutrition and income

13. • Stemborer control
• Striga control
• Fodder & milk production
• Climate change adaptation
• Climate change mitigation
• Soil fertility improvement
• Aflatoxin control
Benefits of Push-Pull

14. Climate smart push-pull controls stemborers and
effectively reduces ear rot and mycotoxin infections
Our recent study
showed that push-pull
not only significantly
reduces stemborer
damage but also
mycotoxin and ear rot
infection of grains.

15. Way forward………..
Efforts to elucidate
mechanisms of suppression of
mycotoxins by push-pull
technology are on-going; and
will provide an opportunity to
manage ear rots and
mycotoxins in maize