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Management of Rice Planthopper and Related Virus Diseasesin Mekong Delta, South Vietnam

Ho Van Chien, Le Quoc Cuong, Do Van Van (SRPPC)

AbstractBrown plant hopper outbreaks associated yellowing syndrome has been reported

and recognized as a serious threat to rice production in South Vietnam since 2006.

Rice grassy stunt virus (RGSV) and rice ragged stunt virus (RRSV) were detected by

ELISA test from both rice leaf and BPH samples either singly or dually. For BPH

associated viruses management using 3 Reduction - 3 Gains, Escape strategy,

Community mass-rearing and applying of Metarhizium anisopliae, the production

process of M.a. to control BPH at farmers household and Pest Management using

Ecological Engineering. These programmes were successful in controlling the

spread of BPH outbreak and the spread of the viral diseases, allowing Mekong delta torecover from production loss within a short span. Combination of formal and applied

research, the efficient system of generating field information involving farmers

themselves, the proactive link of farmers with extension agents and the effective

diffusion of information by media accounts for such success.

Keywords:Brown plant hopper, yellowing syndrome, virus, ecological engineering.

Introduction :

The Mekong River delta region is a major food bowl of Asia. Seventy-two percent of

the Vietnams rice production comes from Mekong Delta and supplies an average of 18million metric tons of rice annually. Rice production growth has been attributed to two

factors: 1. yield increases due to use of high-yielding varieties that were efficiently

responsive to fertilizer inputs, and 2. increase cropping intensity with two or three main

cropping seasons per year and even seven cropping seasons in 2 years.

Mekong Delta however, presents a highly vulnerable agroecosystem wherein pest

epidemics cause extensive damage. Among the pests, brownplant hopper (Nilaparvarta

lugens) is a major threat in extensive rice paddies of Mekong Delta Region. In 1975,

Mekong Delta experienced massive infestation of brown plant hopper (BPH). The

epidemic may have been exasperated by the drastic adoption of high-yielding modern

indica rice varieties that intensified rice production in the region. However, suchtransformation created susceptible environment for BPH population to increase.

Despite introduction of varieties such as TN73-2 and IR 26 that possess high level BPH

resistance, BPH was able to overcome varietal resistance by evolving into a second

biotype in shorter time (Huynh, 1977; Xuan and Huynh, 1979 as cited by Huynh 2008).

The problem of BPH-resistance was overcome with the successful selection of an IRRI-

developed variety IR 36 found to contain a recessive gene resistant to BPH biotype 2.

This enabled the Vietnamese government to effectively contain the BPH outbreak such

that rice production was able to recover in 1980 and rice farmers were able to expand

and intensify their rice production making Vietnam a major rice exporting country by

1989 (Huynh, 2008).

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From 1990 to 1997, Vietnam was able to effectively contain the areas damaged by BPH

attacks with combined strategy of using resistant varieties and implementation of

integrated pest management program. Along with system-wide implementation of

Farmer Field Schools on IPM, extensive education utilizing mass media effectively

informed farmers of the dangers of excessive use of pesticides. Farmers reportedly were

able to reduce the frequency of their pesticide use from 3.4 to 1.6 times per season afterthe media campaign in 1994 (Escalada etal, 1999 as cited by Heong etal, 2008).

Despite these efforts, socio-economic factors driven by the global increase in rice prices

over the last five years have enticed farmers to further intensify their production

systems by increasing the amount of fertilizers, and correspondingly increasing the

frequency of insecticide application in their farms. Promotional advertisements by

pesticide companies were dominating the airwaves of both television and broadcast

media.

In 2006, a resurgence of brown plant hopper attacks was reported and the extent of

damage was visually captured by manifestations of massive yellowing calledhopperburn in the field. Area affected by BPH in 2006 cropping season hiked to more

than 100,000 hectare levels (Fig. 1). Monthly migration of BPH adults were observed

and increase in BPH attacks have been closely linked to asynchronous cropping seasons

brought by increase in cropping intensity. Rice ragged stunt virus (RRSV) and rice

grassy stunt virus (RGSV), two known rice diseases vectored by BPH that cause

hopperburn were observed to be prevalent in more than 80 modern and local varieties

that are planted using direct-seeded method in South Vietnam.

Figure 1. Infected area by BPH from 1997 to 2010 in three rice cropping seasons in each year.

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Increase in BPH may have also stemmed from the use of nitrogenous fertilizers and

misuse of broad-spectrum insecticides (Lu and Heong, 2008; SRPPC, 2010). Escalada

etal (eds) (2008) noted that growing adoption of aromatic rice varieties such as

jasmine may have influenced farmers to increase the use of insecticides such asfipronil and imidacloprid, causing disruptions in the ecosystems balance and function

3

(%) Infected area byVirus

(%) Infected area pertoatal area cultivation

(%) BPH carried virusin Mekong Delta

(%) BPH carried virusin eastern part of MRD

Figure 2. Percentage of BPH carried viruses and (%) infected area by virus / total area ricecultivation from 2005 to 2011

(%) BPH carried Virus

Total Infected area by BPH Total Infected area by Viruses

Infected area by BPH Infected area by Viruses

Figure 3. Total area infected BPH and viruses during 3 seasons in the year from 2005-2011

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to regulate pests. BPH infestation were higher in winter-spring cropping season

followed by summer-autumn and lower in autumn season which follows also intensity

of rice production interms of area planted (see Fig. 1). It was observed that during the

outbreak BPH density per unit area were also at its highest level reaching 10,000-

20,000/m2.

In 2006, some 700,000 tons of rice was reportedly lost to BPH attacks, prompting the

government to impose export restrictions (Escalada, etal (eds), 2008). In the winter-

spring cropping season of 2007, more than 270,000 hectares of rice lands in the

Mekong delta were affected by brown plant hopper (SRPPC, 2010).

The magnitude of the problem created by the brown planthopper attacks prompted

Vietnams Prime Minister to issue instructions, official telegrams and decisions that

mobilize its bureaucracy from the national to local levels to implement urgent measures

to prevent and control BPH and the rice virus diseases and pass pertinent policies to

support such actions. The Ministry of Agriculture and Rural Development (MARD),

after closely monitoring the BPH situation, dispatched six instructions, six officialtelegrams, six decisions and 3 official reports submitted to the Prime Minister,

announcements to provinces and cities and concerned government agencies on how to

prevent and manage the BPH and virus diseases. MARD officially announced an

epidemic of RGSV and RRSV in the Mekong Delta and Southeastern regions on

October 19,2006 (SRPPC, 2010).

Among the measures employed to control the epidemic was for the Vietnamese

government to use pesticides to manage the outbreak. According to reports from 22

provinces and cities within the Mekong delta and Southeastern region, some 1,121.84

tons of pesticides in 2006 and winter spring crop 2006-2007 was subsidized, in which:

272 tons were reportedly released from the National reserve sources; 849.84 tons were

bought using the national budget (SRPPC, 2009).

Pesticide resistance build-up on pest population is a major concern especially in the

Mekong Delta. There was a two-hundred fold resistance of BPH populations to 2

commonly used insecticide active ingredients such as inidaclooprid and fipronil

(Escalada, etal (eds) 2008).

In search of measures that will effectively respond to the BPH epidemic and to address

the concern brought about by the excessive use of pesticides, a parallel BPH

management technique, dubbed as escape strategy was developed in Autumn-Wintercrop 2006.

Brown Plant Hopper Associated Virus Diseases Management in the south of

Vietnam

In order to analyse the experience of the 3 Reduction 3 Grains, BPH escape

strategy and other complementary practice such as the use of biological control in

mass-rearing parasitic pathogen Metarhizium anisopliae (Ma). Particularly, setting up

Ecological Engineering for pest management using natural biological control in light

of the concept of a sustainable crop production intensification.

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The contributions of the escape strategy and the use of ecological engineering as

sound pest management practices in controlling pest epidemic such as BPH, one of the

negative effects brought about by the pressure of an intensified rice production system;

identify what enabling factors and elements enabled the scalling up Eco-Eng program

to effectively control BPH in rice farming communities in the south of Vietnam; cite

possible constraints and factors that hinder wider adoption of such managementpractices and draw recommendations on how these can be best approached.

Brown Plant Hopper Escape Strategy programme

Escape strategy, simply put, is a practical technique that farming communities can

employ to prevent the spread of brown planthoppers and the spread of its vectored

diseases. The strategy involves synchronizing seeding to avoid disease transmissions

based on light trap data and 3 Reductions 3 Gains. On the other hand, BPH become

to pesticide resistance when applying pesticides to seed treatments to prevent the spread

of viral diseases. Such actions would require collective decision-making that banks on

understanding of the dynamic and behavior of the BPH population using monitoringtools such as light traps.

The development of escape strategy was based on the results of serious experiments,

first set up screenhouse testing studying the critical periods of disease transmission of

BPH. In their study involving controlled release of BPH and virus inoculation into

screened direct-seeded boxes at different rice growth stages, it was observed that

disease symptoms manifest in rice plants that were inoculated with disease 7 and 14

days after sowing (DAS). The results also suggest that the diseases tend to infect

younger (those planted before 20 DAS) than older plants. Outside of screenhouse

mesh, the reaction of the plants to yellow dwarf and rice grassy stunt virus were similar.

It was also observed that employing seed treatment in different doses where able to

reduce the density of BPH, but not the rate of infection by yellow dwarf and rice grassy

stunt virus manifested in yellowing of plants (Nguyen et al, 2008). These findings of

Southern Regional Plant Protection Center (SRPPC) were instrumental in the

determining the critical duration for virus transmission and the critical periods of

sowing to avoid virus infections that would be the guide posts in the development of the

escape strategy. When the Vietnamese Government declared calamity in 2007, a

Directory board of BPH control was formed. Among the activities that were set up

include: the establishment of light traps at all levels to monitor the incidence and

migration activity of BPH , the provision of technical advise on how to evade BPH

through synchronous planting and proper application of insecticides and cooperationwith FAO in setting up IPM field demonstration trials at the community levels.

With the technical support from FAO, field demonstrations were subsequently

established by SRPPC in 359.4 hectares involving 452 farming families in seven

provinces, namely: Can Tho, Tra Vinh, Soc Trang, Dong Thap, Tien Giang and Long

An during the summer-autumn cropping season. The field demonstration trials aimed at

validating the results of the screenhouse testing by testing different sowing time -

before and after the migration of BPH.

Two kinds of field demonstration trials were established: 1. involving 4 varieties and 2.

involving 12 varieties of certified seeds. The first experiment served as control whereinrice varieties where sown before BPH migration. The second experiment served as

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demonstration plots wherein rice varieties where sown into the field after the BPH

migration.

Light traps were established within 40-60 hectare radius to determine the peak of

arrivals of BPH migration. A group of 20-50 participating farmers count the number of

BPH catches in the light trap each morning.

The numbers are plotted with the sub-PPD technician or in some districts, submitted

directly to SRPPC for consolidation and interpretation.

The decision to escape the BPH follows the general rule to synchronize sowing

three days to one week after the peak of arrival (Figure 4). In some of the districts, the

sub-PPD technician decides when is the best time to do synchronize sowing and convey

the message back to the farmers within the day. For SRPPC, an advisory is broadcasted

via radio and television to reach wider scope of farmers in the specific district where

forecasts have been made.

The field demonstration plots comparing 12 varieties indicated the different responses

of the varieties to the two diseases - RRSV and RGSV. Results also shown that

varieties such as Jasmine 85, OM 4498, MTL 385, OM 1490, OM 2517, OM 3536 and

OM 4872 have good resistance to yellow dwarf syndrome.

Figure 4. Light trap data in the field demo. site of Dong Thap province. Seed sowing time

from April 27 to May 3, 2007.

The field-demonstration trials also yielded other positive findings. Among these:

a. Rice fields were able to successfully escape the BPH damage despite

high counts recorded in light traps;

b. There was careful monitoring resulting to better management of the

fields and consequently reduction and at times absence of insecticide use;

c. Farmers showed positive response and enthusiasm with their own

results.

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d. Synchronous planting to escape BPH contamination will not work if a

third cropping (autumn-winter) is still applied. The light trap catches high BPH

densities during the first cropping season. This suggests that a collective,

community-level response is needed to address BPH (SRPPC, 2010).

In the succeeding planting seasons, the Plant Protection Department (PPD) promoted

the adoption of this escape strategy into other communes, districts and provinces in

the Mekong Delta region. The Sub-Plant Protection Department (SPPD), the main

extension agency implementing Farmer Field Schools (FFS) in the provinces integrated

the escape strategy in FFS on IPM in the communes. Such endeavors were likewise

supported by the Local Peoples committee, Farmers Union and the Farmers Group in

the hamlets and subdistricts. In the dry season of 2007, the escape strategy was

observed in about 1.2 million hectares and was further expanded to 1.4 million hectares

in the wet season of 2007.

The data collated from the light traps are also being used by the SRPPC to understand

and analyze the migration patterns of the BPH in the Mekong Delta and the South

region. Risk zones of BPH infestations within the region were determined (Figure 5).

In the dry season when BPH attacks areas of Binh Duong , Ho Chi Minh and some

areas of Long An, data have shown that BPH tend to travel southward to Tien Giang,

Dong Thap, An Giang, Kien Giang, Hau Giang and Soc Trang and then go back to

northern provinces in the wet season. From the Southern region, BPH then tend to

emigrate west to Cambodia from July to August in wet season yearly. The

determination of the risk zones are crucial for SRPPC in forecasting the potential path

of BPH migrations and would help prepare concerned local institutions for the

impending arrival of BPH in their respective jurisdictions once BPH have attacked aparticular risk zone.

Numbers of rice growing area using escape strategy during 2007-2011 have increased

from 800,000 ha to 1,300,000 ha per total 1,600,000 ha for each season. This reason

cause of lack labors for harvesting at the same time. Now, there are 10,000 harvesting

machiners (6,000 threshing and harvesting combination machines and 4,000 harvesting

machines within row-line arrangement), Harvesting by machinery to avoid post-harvest

loss!

The use of biological agent Metarhizium anisopliae against Brown plant hopper

One factor that has been attributed to the resurgence of BPH attacks in Mekong Deltaregion is the breakdown of ecosystem services consisting of both pest invasion

resistance and pest regulation (Heong, Chien and Huan, 2008). Frequent and extensive

application of chemical insecticides during the early crop stages also adversely affect

BPHs natural enemies population.

Community mass-rearing and applying of Metarhizium anisopliae, the production

process ofM.a. to control BPH at farmers household was developed and was initiated

in Soc Trang Province in October 2008 by the team of Dr. Tran Van Hai of Cantho

University (Chien, 2010. personal comm). It has become an integral component of the

current IPM FFS classes facilitated by Soc Trangs Sub-plant protection department

(SPPD), spores ofM.a. cultured from the laboratory of Cantho University are deliveredto farmer groups for mass propagation and eventual application in farmers fields.

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Risk zone 1Risk zone 1

Risk zone 2Risk zone 2

Figure 5. Risk Zones of BPH in South VietnamSource: SRPPC, 2010.

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During FFS, farmers are taught how to do mass propagation following a series of steps.

First, farmers sterilize steamed rice contained as propagation media in folded plastic

bags for 2 hours. In an improvised hooded flume, a farmer divides the culturedM.a in

petridishes into 6 parts and carefully transfers 1 part into the plastic containing the

propagation media. The folded plastics are then sealed using cotton knot, labeled

accordingly and are incubated under natural condition of farmers households.Successfully mass propagated media show grayish powdery growth in steamed rice and

after 10-14 days of natural incubation, farmers can make use of mass-producedM.a. in

their field trials or respective fields.

Farmers during the FFS also discuss the application ofM.a.in the field. Five bags of

mass-propagated media are diluted in 400-500 liters of water and are sprayed in the

fields when they observed that there are 1-2 brown plant hoppers. The application can

be done twice : first at 25-30 days after sowing and the second at 45-50 days after

sowing. After 5-7 days, farmers can visually observe the effect ofM.a by looking at the

scale of infections in brown plant hoppers in their fields.

Already, the use ofM.a is gaining attention not just in Soc Trang Province but also in

nearby provinces within Mekong Delta region, namely: Cantho, Long An, Dong Thap

and Tien Giang in more than 2,320 hectares since cropping season 2008- 2009. In

2009, the production process ofMetarhizium anisopliae to control BPH at farmers

household was evaluated and recognized by the MARD as an advanced technology in

agricultural production.

Figure 6. Farmer doing mass-culture propagation ofMetarhizium anisopliae.

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Figure 7.Ma. Incubation under natural conditions of farmers household(Application after 10-14 days)

Figure 8. Infection from 5-7 days after application ofMa. Product.

Ecological Engineering

Dr. KL. Heong (IRRI) introduced a new concept of ecological engineering and very

soon this idea is adopted by farmers. The flowers-on-bunds is not only bringing back

bees and predators to the environment, it is also making the rural landscape beautiful. In

early 2009 and SRPPC carried out two rice field demo. sites with 30 ha of each in Cai

Be and Cai Lay districts, Tien Giang province in the dry season 2009-2010. Today,

more than 2,000 ha as demonstration rice fields using Ecological Engineering for BPH

Associated Virus Diseases Management in seven provinces in the south of Vietnam.

Result and Discussion

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In a scoping study done on management of BPH/ virus problem in Vietnam (2007),

farmers perceived that escape strategy as the most effective among the virus control

strategies introduced by the SRPPC.

The development and adoption of the escape strategy and the use of natural biological

control i.e. M.a and Ecological Engineering can be considered as sound practicesthat can effectively address specific problem brought by intensification pressures on

extensive rice production systems. Most measures complements and uses the

underlying principles of action-threshold levels earlier advanced by the integrated pest

management.

Until 2011, the scale of adoption of the Ecological Engineering, itself is an indication

of its effectiveness. At close look, there are elements in the development and

implementation of the escape strategy and Eco-Eng that can be considered

contributory to such success. Among these:

Employment of systematic approach complementing formal with applied research

under farmers specific conditions hastened the deployment of a response to an urgentproblem.

With community level mobilised, the process of development of the escape strategy

and Eco-Eng in particular capacitated farmers to appreciate the importance of regular

field monitoring with light traps as tool, gain better understanding of the nature and

dynamics of the BPH and awareness of the implications of frequent use of insecticides

in the process, leading to better management of their fields.

Except for the establishments of the light and air traps, escape strategy and nectar

flower seeds did not involve procurement of costly agricultural inputs but more of

mobilising the local expertise of farmers and extension agencies.

The cooperation and collective action of different institutions (FAO-IPM, PPD andIRRI scientists through SRPPC, Peoples Committee, Farmers Association and the

farmer groups at the community levels) are crucial. Given that it is difficult to observe

synchronous planting particularly in the communities where access and availability of

irrigation is not a problem. The escape strategy and Bund nectar flower growing

showed that it can be possibly done.

The use of effective media (both broadcast and print) enabled the SPPD and SRPPC

to disseminate the information to more farmers making nectar flower growing and

synchronous planting to be more effective.

The following are the potentials and the benefits of the escape strategy and Eco-

Eng in advancing sustainable rice production in the Mekong Delta.

1. Reduction in pesticide applications. Results of the demonstration plots (Figure 9)

revealed significant reduction in chemical insecticide applications. Remarkable

reduction is noted in the frequency of insectide use from an average of 4-5 times drop

down to zero or 1 time in rice cropping season. This translates to reduction of input

cost. Average computation from the seven provincial demonstration fields showed an

average of 25% reduction in input costs (Figure 11). After 5 years of extensive

implementation of the escape strategy, and 2 years with Eco-Eng scalling up,

SRPPC data revealed that frequency of insecticide spraying reduced from 5-6 times to 0

or 1 time. In some instances, farmers even do away with pesticide use.

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2. Improvement in Productivity . Average yield in demonstration plots suggest that

yields in escape strategy and Eco-Eng demonstration fields were slightly higher

than control fields (Figure 10). Although the difference is not significant, the

improvement can be attributed to the reduction in the damage of BPH and its associated

viral diseases.

Valuing the incremental increase in yield and the savings from reduction of insecticide

use, there was an average

of 1,650,000 VND (# 80

USD) increase in net

income (benefit-cost) in

demo. fields.

Ensuring food security. The extensive adoption of the escape strategy and Eco-Eng

was estimated to have contributed Food Safety in Household and National Food

Security as a result of reduction in area damaged by BPH and in area damaged by the

viral diseases.

Deployment and observance of the escape strategy or Eco-Eng alone is not enough.

Farmers may not be able to sustain the practice in the long-run. BPH infected area

correspondingly increased in 2007 and 2008 and declined in 2011 (Figure 12).

Emergence of new intensification challenges driven by a different kind of pressuremay lead farmers to abandon such practice. Subsidies for pesticides continue to prevail

and is still supported by the Government. BPH may also evolve into newer more

resilient strains and different kinds of insect pests may also emerge. This would require

strengthening agroecosystems function, particularly using Ecological Engineering

for enhancing natural enemies population so that it can effectively regulate the pest

population. At the farmers levels, benefits of the use of Eco-Eng as complementary

to escape strategy are described.

11

7.2

7.25

7.3

7.35

7.4

7.45

Ton/ha

Demo.

Contro

Fig. 10. Average of rice yield

Insecticide

Fungicide

Figure 9. Average frequency ofpesticide application in DemonstrationFields.

Figure 11. Average Input Cost (left) and Net-Income (right) Comparison in Field

Demonstrations.

0

5

10

15

2006 2007 2008 2009 2010 2011

% DT nhi?m r?y % DT nhi?m VL,LXL

2006 2007 2008 2009 2010 2011

,

% DT nhi ?mr?y %DT nhi ?mVL,LXL(%) Infected area of virus diaeases

Fig. 12. Percentage (%) of total infected area of BPH and virus diseasescompare with total area rice cultivation during the year (2006-2011)

6 2007 2008 2009 2010 2011

,

% DT nhi?m r?y % DT nhi?m VL,LXL(%) Infected area of BPH

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On top of the positive contributions identified by farmers, we observed that the

promotion of Eco-Eng as potential livelihood project that women-farmers can

actively venture, is an add-on offering additional income for farmers groups. In the

process, this may further strengthen working relationships within farmers groups.

For Ma., although there are limited literatures citing side-effects to non-target

organisms, Stolz (1999) reported high susceptibility of two kinds of parasitic wasps

(Bracon hebetor and Apoanagyrus lopezi) to Metarhizium anisopliae var. acridum.

Highlights of the ongoing Escape strategy and Eco-Eng, the women-members were

already doing the growing of nectar flower on bunds for one to five cropping seasons.

They noted the following positive gains:

Method controls other insect pests. They also observed that Eco-Eng

not only infected BPH population but also attacks other insect pests such as

leaffolders and stemborers. When asked about their observation on natural

enemies of bund flowers, the women farmers that they have not only yet

observed natural enemies on bund flowers but also found them in their

fields; Improvement of farmers health and environment. The women

complained that spraying chemical insecticides exude bad smell that makes

them sick. The use of chemical pesticides also were contaminating their

water. With the use of Enco-Eng, the women-farmers noted that many

small fishes living in canals.

Farm diversification is encouraged. Rice-fish culture was a common

practice in An Giang and Tien Giang provinces but was stopped because the

bad smell from pesticide use were killing the fish. The women said that they

can revive the culture and fish can be protected by the method.

Reduction in cost of pesticide control. Comparation between the escape

strategy and Eco-Eng and farmers practices on the average of insecticide

sprays from 5 times drop to 1, farmers experienced 85-90% reduction in

pesticide cost.

Improvement in their yield. The farmers mentioned that there was no

reduction in yield. In the three cropping seasons that they have been

observing both the escape strategy and using Eco-Eng, yield were

sometimes even higher. They attributed this to the improvement of water

and soil quality as a result of improved management practices.

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Figure. 13. Demonstration field of Eco-Eng in Chau Doc district, An Giangprovince (Dry season 2012)

Figure. 14. Demonstration field of Eco-Eng in Chau Phu district, An Giang province(Wet season 2011)

Figure. 15. Two species of BPH egg parasitoids in the rice field of Eco-Eng Demo.Source: Nguyen Van Huynh, Can Tho University

Conclusions and Recommendations:

The escape technique and the community-level production and using of Eco-Eng

as management strategy to manage and control BPH and viral disease epidemic present

a case of how an intensification-associated problem can be best addressed by

maximizing existing understanding of insect pest behavior and natural biodiversity tostrengthen agro-ecosystems service to regulate itself. Such self-regulating function

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means allowing natural pest population to increase by reducing times of pesticide

application.

The escape strategy was successful in controlling the spread of BPH outbreak and the

spread of the viral diseases, allowing Mekong delta to recover from production loss

within a short span. Combination of formal and applied research, the efficient systemof generating field information involving farmers themselves, the proactive link of

farmers with extension agents and the effective diffusion of information by media

accounts for such success.

Escape strategy and Eco-Eng should be complemented with other practices such as

the use of NPK balance, soil and water management...This would allow farmers to

further innovate in their own farms while they accumulate experience and gain

understanding of agroecosystem relationships.

Efforts towards biodiversity-oriented intensification will remain futile, however, if

policies and programs are not supportive or negate the very principle of escapestrategy or use of Eco-Eng natural biocontrol as pest management strategies.

References:

Chien, HV. Personal communication. April 29, 2010.

Escalada, MM., Huan,NH, Heong KL (editors). 2008. The Brown Planthoppers and Virus Problems inVietnam A scoping study. Proceedings of the Final Consultaion Workshop held in Ho Chi

Minh City, Vientam. 8 January 2008. Ministry of Agriculture and Rural Development,

Vietnam. CDHai, TV, Trinh TX, Bui XH, Dang, TC. 2010. Production Process of Entomapathogenic Fungi

(Metarhizium anisopliae) to Control Rice Brown Planthopper at Farmers Household in Soc

Trang Province. Cantho University and Soc Trang SPPD. Powerpoint presentation.Hai, Tran Van. Personal communication. April 30, 2010.Heong, KL, HV Chien and NH Huan, Contributing Factors to the brown planthopper virus outbreaks

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Nguyen, HH, HV Chien, PV Du, LH Hai, PV Quynh, MT Phung. Implementing the escape strategyagainst the outbreak of RGSV and RRSV diseases in rice in the Mekong Delta Vietnam . In

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Nguyen, Van Huynh. The BPH (Nilaparvata lugens) management for rice production in the MekongDelta. InProceedings of the Final Consultaion Workshop held in Ho Chi Minh City, Vientam.

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Reuters. Philippines ups rice import limit to over 3-M tons. February 2,2011. .

Southern Regional Plant Protection Center (SRPPC). 2010 The escape strategy in the Mekong Delta

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