K.L. Heong IRRI Rice Seminar Series Current position: Insect ecologist, Senior Scientist, IRRI Education and training: PhD and DSc Imperial College, UK. Fellow of Malaysian Academy of Science Fellow of the Third World Academy of Science Fellow of the World Academy of Art and Science Work experience: Malaysian Agricultural Research and Development Institute (MARDI) Research highlights: Arthropod community structure in rice ecosystems Impact of insecticides on arthropod food web structures Insect predator-prey relationship in rice ecosystems Biodiversity and ecosystem services in rice ecosystems Farmers’ pest management decision making Use of mass media and education entertainment approaches to reach millions of rice farmers Awards: Charles Black Award (US Council for Agricultural Science) Prize for Agriculture (Third World Academy of Science) Gold medals – Agricultural Development (Government of Vietnam) Excellence Prize (Malaysian Plant Protection Society)
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K.L. Heong
IRRI Rice Seminar Series
Current position:
Insect ecologist, Senior Scientist, IRRI
Education and training:
PhD and DSc Imperial College, UK.
Fellow of Malaysian Academy of Science
Fellow of the Third World Academy of Science
Fellow of the World Academy of Art and Science
Work experience:
Malaysian Agricultural Research and Development Institute (MARDI)
Research highlights:
Arthropod community structure in rice ecosystems
Impact of insecticides on arthropod food web structures
Insect predator-prey relationship in rice ecosystems
Biodiversity and ecosystem services in rice ecosystems
Farmers’ pest management decision making
Use of mass media and education entertainment approaches to reach millions of rice farmers
Awards:
Charles Black Award (US Council for Agricultural Science)
Prize for Agriculture (Third World Academy of Science)
Gold medals – Agricultural Development (Government of Vietnam)
Return of the Green Revolution Menace with New Vengeance
K.L. Heong
Summary of Seminar
• Current situations of problems with planthoppers and related virus diseases
• Broad look at the problems and why they occur.
– Ecological reasons for such situations
– Root causes beyond the rice ecosystems
• Ecological engineering initiatives to restore resilience
• Mitigation options to reform pesticide policies regulations and marketing
UNWELCOME HARVESTAfter Conway & Pretty 1991
• Green Revolution - undisputed successes
– HYVs enabled increase in rice production
– Contributed to poverty reduction, food security
• Limitations
– Environmental degradation
– Created new threats – the planthoppers
• Doubly GREEN Revolution Conway 1997
– Increase food at an even greater rate
– So it in a sustainable manner without damage to
environment and its services
– Ensure equity
Menace 1 –Brown Planthopper (BPH)
Short winged
form
Long winged
form
Cabauatan et al 2008
Virus diseases
New Menace 2 –White backed planthopper (WBPH)
Long winged form
Short winged form
New virus carried by WBPH
• Discovered in Guangdong in 2001.
• Transmitted by WBPH
• Southern Rice Black Streak Dwarf virus (SRBSDV) because of its similarity with the RBSDV carried by sBPH in temperate areas.
• Spreading in southern provinces of China, Northern Vietnam areas.
middle-season rice damaged
Spread of new virus disease
Found in maize inShandong province
First discovered in 2001
Zhou 2010
Found in Kyushu Japan in 2010
Planthoppers are r – strategists
Landscape biodiversity
High……………….Low
Low habitat stability
escape from natural
control
r strategists tend to develop exponentially when they “escape” from natural control
When the natural enemy ravine is in place
Populations low
When the natural enemy ravine is removed
Population develop exponentially
Summary from Synoptic Model
• In habitats with low stability, pest population growth rates tend to increase when “released” from biocontrol services resulting in outbreaks.
• Rice production systems that have low landscape biodiversity will need to conserve biocontrol services more to avoid “release of pests” or outbreaks.
• Pests that strive in habitats with low stability have typical life strategies
– r strategists with high adaptability.
r - pests
• Common characteristics:– High reproductive capacities
– Small size, short life cycles
– High migratory tendency - essential for movement
from the “dying habitat” to a new one.
– Exogenous invaders into a crop.
– Normally not pests in low densities but can
occasionally outbreak when released from natural
control.
– Because of the ephemeral nature of the crop
habitats it is necessary to consider managing their
population on a regional scale – Macro level
(Southwood 1977).
Population ModelContinuous model
Nt + 1 = Nt exp {r(1 – Nt /K)}
Finite rate of increase λ = exp rr is per capita rate of increase
r ≈ (ln Ro)/Tc
Nett reproduction rate and generation time
K is carrying capacity
r – K continuumbiological strategies
• Rice planthoppers are
– Monophagous – live only on rice
– r strategists
– Mobile and invasive
• Sustainable strategies need to focus on population management at the macro level and not just developing “killing” methods.
• Using insecticides to control such pests is like “throwing petrol into fire” – completely unsustainable
Pest storms
in
Thailand
China
Indonesia
Hopperburn occur in patches with Hopperburn occur in patches with
Effect of early season sprays on ecosystem services
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Weeks after transplanting
Ecossytem service
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Weeks after transplanting
Ecossytem services
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Weeks after transplanting
Hopper invasion
Early season
sprays increase
vulnerability to
invasions
Ecosyste
m s
erv
ices
Outbreak
More pesticide – more eggsResurgence
More pesticide – more BPH eggs
Resurgence – fipronil increase fecundity
2.3 X
Hopperburn in sprayed spots in Cantho province
Pictures by Pham van Quynh
No effect of insecticide sprays on plant hopper eggs in refuge
Small size and soft body make natural enemies more susceptible
BPH
Cyrtorhinus
Anagrus
Wolf spider
Sprayed rice fields are like mine fields to predators
and parasitoids in search of prey
Spider Biodiversity, Bund Biodiversity
and Pesticide Use
•High species richness
•High spider density
•Example Danzhou S=70
•Moderate species richness
•High spider density
•Example Lingshui S= 55
•Low species richness
•Low spider density
•Example Haikou S= 37
•Low species richness
•Low spider density
•Example Sanya S= 36
Bu
nd
Bio
div
ers
ity
Low
High
HighLow Insecticide Use
• After the sprays hopper eggs hatch into an enemy free environment and enjoy “exponential growth”.
Norowi
Insecticides cause BPH to produce
more long winged formsMore pesticide – more migration
The ecology of planthoppers well documented
• Impact of insecticides on herbivore-natural enemy communities in tropical rice ecosystems. Heong & Schoenly
• The role of biodiversity in the dynamics and management of insect pests of tropical irrigated rice – a review. Way and Heong
• Insect pest management in tropical Asian irrigated rice. Matteson
• Planthoppers – New threats to the sustainability of intensive rice production systems in Asia. Heong and Hardy
New reviews to follow
• New book on “Rice Planthoppers” from the ADB-IRRI Rice Planthopper Project.
• New paradigms in Rice hopper resistance
Horgan et al
• Asia’s planthopper problems: The re-emergence of an old enemy. Horgan and Heong
• Resurrecting the Ghost of the Green Revolutions Past: The Rice Brown Planthopper as a Recurring Threat to High Yielding Rice Production in Tropical Asia. Bottrell and Schoenly
Insecticide resistance
0
5
10
15
20
25
30
35
40
45
50
Philippines Thailand Vietnam China
0
2
4
6
8
10
12
14
Philippines Thailand Vietnam China
0
0.5
1
1.5
2
2.5
3
3.5
Philippines Thailand Vietnam China
X6
X32
X127
X2
X59
X33
X0.9
X19
X27
BPMC
Imidacloprid
Fipronil
Biodiversity, ecosystem functioning, and ecosystem services
NegativesPesticide promotion by private and Public sectorsGovt subsidies, free distributionsLow costs of pesticidesPesticide misuses
NegativesPesticide promotion by private and Public sectorsGovt subsidies, free distributionsLow costs of pesticidesPesticide misuses
Structures/Policies favoring NegativesInadequate pesticides regulatory systemEcosystem services not factored into policiesIncentives for short term profit gainsLack incentives for sustainable practicesAccess to emergency pesticide allocations
Structures/Policies favoring NegativesInadequate pesticides regulatory systemEcosystem services not factored into policiesIncentives for short term profit gainsLack incentives for sustainable practicesAccess to emergency pesticide allocations
China’s Pesticide Production (metric tons a.i.) 2000 – 2009.
[source: ICAMA]
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
2000000
1990199219
94199619982000200220
0420
062008
Mil
lio
n U
S$ Chn exp
Jpn exp
Kor exp
EU exp
Data from FAOSTAT updated June 2011
EU exports
China
exports
0
20
40
60
80
100
120
140
160
180
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008M
illi
on
US
$
Indonesia Thailand Viet Nam Philippines IndiaData from FAOSTAT updated June 2010