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Collaboration for Agriculture and Rural Development CARD Program176 INTEGRATED PEST MANAGEMENT USING WEAVER ANTS AS A MAJOR COMPONENT FOR CASHEW Project title: Implementation of the IPM

Collaboration for Agriculture and Rural Development (CARD) Program

176

INTEGRATED PEST MANAGEMENT USING WEAVER ANTS AS A

MAJOR COMPONENT FOR CASHEW

Project title: Implementation of the IPM program using weaver ants as a major component for

cashew growers in Vietnam

Project code: CARD 029/05/VIE

Author(s): Prof Keith Christian1, Dr Renkang Peng1, La Pham Lan2and Nguyen Thanh Binh2

Project Implementing organisations:

1

Charles Darwin University, Australia 2

Institute of Agricultural Science of South Vietnam

SUMMARY

Cashew is a very important crop in Vietnam, and the government has designated cashew development as a national priority Productivity of cashew has increased since 2002, but the extensive use of pesticides has caused health problems to farmers, their animals and the environment The cashew IPM programs using weaver ants as a key element developed at Charles Darwin University (CDU) do not involve high toxic insecticides, but result in high yield and nut quality This project is to use the CDU cashew IPMs to develop and implement

an integrated cashew improvement (ICI) program that will work under Vietnamese conditions.

An ICI manual and an ICI photo book that work in Vietnam have been developed at 500 and

3000 copies, respectively, and used in the TOT and FFS training, and the positive comments

on the materials are received The project has produced 113 competitive TOT trainers, who have successfully conducted 98 FFSs, resulting in 2,448 knowledgeable farmers Demonstration orchards produced 13% more net profit in the ICI plot than in the farmers’ plot Over 95% of farmers were pleased with the FFS training contents, methods and the results of demonstration orchards The project has produced benefits for small-holders and aspects of capacity building, and improved farm environment, farm health and crop sustainability There is a high demand of FFS training by local cashew growers.

1 Introduction

Cashew (Anacardium occidentale) is an

important crop in Vietnam, and the

government has designated cashew

development as a national priority The area

growing cashew is about 430000 ha located in

Central Highlands, South Central Coast and

South East region Cashew is planted mainly in

inverse soils that are low in fertility and with

low precipitation For years, cashew plants

were considered as a forestry plant so that the

growers did not consider any intensive

techniques such as fertilization or plant

protection (David, 1999) When the decree of

Prime Minister signed in 7 May 1999 on the

development of cashew production was

released, the growing area of this plant for

exports expanded rapidly in Southern Vietnam

However, the productivity of cashew is low

because of serious damage from insect pests

and inadequate farm management Insect pests

of cashew plants has identified that

lepidopterans and hemipterans are

predominant (An, 2003; Lan et al., 2002)

Generally the use of insecticides is a common

practice by farmers to control insect pests In

some cases the efficacy of insecticides was not

proven due to misuse and farmer use of

insecticides as a preventive tool To achieve

high yields most growers rely heavily on

insecticides, resulting in increased costs, pest

resistance, environmental pollution and the

reduction of natural enemies and pollinators

The suggestion of using a biological agent as

weaver ant (Oecophylla smaragdina) instead

of insecticides is not new but has potential as a

control measure In the Mekong Delta the

application of weaver ants can control insect

pests in citrus orchards and also give fruit with

few blemishes The use of weaver ants as a

biological control agent of insect pests is

common in the Mekong Delta (Barzman et al.,

1999) Scientists from Charles Darwin

University found that an IPM program that

used weaver ants as a key element had been

successfully used by cashew growers in

Australia, Papua New Guinea and

Mozambique (Peng and Duncan, 1999; Peng,

2000, 2001, 2002; Peng et al., 1999, 2004)

Based on the successful examples on citrus

orchards in the Mekong Delta (Vietnam) and

on cashew orchards in Australia and Africa, this project was proposed with the aim of increasing cashew yield and improving nut quality Specific objectives are (1) to conduct TOT training in cashew IPM for TOT trainers

to conduct FFSs in their local region, (2) to develop an IPM cashew curriculum and a series of illustrative posters based on the cashew IPM programs developed in Australia that will work in Vietnamese conditions and (3) to assess the effectiveness of the FFS model in increasing farmer knowledge and reducing pesticide use in cashew production

2 Research contents and methods

2.1 Research Contents

A Start up workshop was held on 5 May 2006

at the Institute of Agricultural Science of Southern Vietnam (IAS) A total of 38 experts who are involved in Vietnam cashew production were invited, they came from plant protection departments, research institutions, universities, non-government organizations, agricultural services and rural departments, an insecticide company and media corporations Organization of Training of Trainees (TOT) classes: Two TOT courses were organized One TOT was held at the sub-PPD of Binh Phuoc province, and the other at the Hung Loc Agricultural Research Center belonging to IAS located in Dong Nai province Two TOT courses have resulted in 60 trainees (30 each), who are currently IPM trainers in rice and vegetables in provincial sub-PPD Because cashew trees are perennial, the period from flowering to harvesting is more important than other periods The TOT courses ran from flowering to harvest At each site, one demonstration cashew orchard was established

to enable trainees to practice Each demonstration orchard is 1.2 ha, divided into two treatments One treatment was managed

by the orchard owner with his current farming practices including insecticide sprays The other was managed by the IPM program The two TOTs of 1st year have been completed, the two TOT of the 2nd year are currently running

A total of 120 cashew IPM trainers will be available at the end of the project

Keith Christian, Renkang Peng, La Pham Lan & Nguyen Thanh Binh

178

Organization of Farmer Field School (FFS)

classes: After finishing the course 60 TOT

trainees will become cashew IPM trainers The

60 IPM trainers will be divided to 30 groups (2

for each group), and each group will run one

FFS Each FFS will take 25 farmers A total of

30 FFSs will be completed in the 1st year and

a total of 750 cashew smallholders will be

trained in cashew IPM In the 3rd year, each

group of “old trainees” (2 trainers) will run 2

FFSs, and each group of “new trainees” (2

each) will run one FFSs,

A Base line survey was conducted in the target

provinces of this project Binh Phuoc, Dong

Nai, Binh Duong, Binh Thuan, Ba Ria Vung

Tau, Dak Lak and Dak Nong provinces

3 Research results and discussions

3.1 Baseline survey - Effectiveness of the

FFS model in increasing farmer

knowledge and reducing pesticide use

in cashew production

The effectiveness of the FFS training on

farmers’ knowledge and farming skills has

been assessed against baseline data Of 197

questionnaires collected from the first year

FFS farmers, over 95% of farmers were happy

with the FFS training contents, with the

training methods, and with the results from

FFS demonstration orchards More that 80% of

the farmers were sure that weaver ants could

control the main cashew insect pests and

would improve cashew yield and nut quality

Over 80% of farmers knew how to use weaver

ants, would use weaver ants, and would tell

their friends and other farmers to use the ants

Farmers’ knowledge about insect pests,

diseases and their natural enemies as well as

general farming skills has been significantly

improved (Peng et al., 2009)

Farmers’ knowledge about the general farming

activities has been significantly improved

Compared to the proportion of farmers

conducting each of these farming activities

before the FFS training, 35%, 49%, 28%, 31%,

and 18% more farmers conducted weeding,

mulching, irrigation, pruning and fertilizer

application respectively after the FFS training

Compared to the proportion of farmers using

insecticides before the FFS training, 24% fewer farmers used insecticides after the FFS training (Table 1 and 2) In addition to this, over 92% of the farmers showed a full understanding of the principles and tactics of conducting each of the above farming activities

Table 1 Number of people who used

insecticides before and after the FFS training Insecticide

spray

Before FFS

After FFS

Total

Pearson Chi-square statistics χ2= 34.329; P < 0.001; df = 1

Table 2 Number of people who used

insecticides and herbicides before and after the FFS training

Herbicide use

Before FFS

After FFS

Total

Pearson Chi-square statistics χ2= 0.352; P = 0.553; df = 1

In the baseline survey, farmers, on average, could only recognise < 1 insect pest species, and 37% of them could not recognise any insect pests After the FFS training, on average, farmers could recognise 3.3 species More than 85% of the farmers could recognise tea mosquito bugs, branch borers and stem-root borers, and over 20% of farmers could recognise thrips, shoot borers, branch borers, red caterpillars and mealy bugs, which are the major insect pests in cashew orchards In our baseline survey, farmers could only recognise

< 1 disease, and 37% of them could not recognise any disease Besides, farmers, on average, could recognise 2 diseases After the FFS, 92% of the farmers could recognise the most important disease ‘anthracnose’ In the baseline survey, a majority of farmers had no knowledge of the natural enemies of the pest species After the FFS training, farmers could recognise an average of 2.2 species of natural enemies, and 100% of the farmers knew weaver ants very well

With regard to the reduction of insecticide use, 91% of the farmers used insecticides before the FFS training, but after the FFS training, only

67% of the farmers used insecticides, resulting

in a 24% reduction (Peng et al., 2009) This

was because insect pest damage was greatly

reduced after using weaver ants in their

orchards However, with the application of the

ICI program, it would expect that the current

level (67%) of farmers using insecticides will

decrease further when farmers get more and

more experience using weaver ants Besides

this, 92% of the farmers demonstrated a full

understanding of when and how to use

insecticides in their orchards (Peng et al.,

2009) In contrast, in baseline survey, 80% of

the farmers experienced various kinds of

poison symptoms during or after the

insecticide operations (Peng et al., 2006a)

3.2 TOT training in cashew IPM for TOT trainers to conduct FFSs in their local region

A total of 113 TOT trainers have graduated from our two-year TOT training (56 in the first year and 57 in the second year (Peng et al., 2008e), and they are very competent in FFS training (Peng et al., 2008c) These TOT trainers have successfully conducted 98 FFSs

in their local regions, resulting in 2,448 farmers having graduated with improved knowledge and farming skills in relation to the cashew ICI program (Peng et al., 2009)

demonstration orchards

3.3.1 Binh Phuoc orchard

Based on the monitoring data, the common

insect pests in this orchard were tea mosquito

bugs (Helopeltis antonii), shoot borers

(Alcidodes sp.), leaf miners (Acrocercops

(Nephopteryx sp), leaf rollers and branch

borer

During the period of pre-flowering flush to nut development (November to March), the damage level of cashew flushing shoots, flowers or young nuts by tea mosquito bugs, shoot borers, leaf miners, aphids and leaf rollers was similar between the farmer’s plot and the IPM plot (P > 0.05; Table 3) However, the average level of developmental nuts damaged by the fruit-nut borer was lower

in the IPM plot than in the farmer’s plot (P = 0.018; Table 3)

Red tea mosquito bug

(Helopeltis antonii)

Blue shoot borer

(Alcidodes sp.)

Leaf miner

(Acrocercops syngramma)

Leaf rollers

Keith Christian, Renkang Peng, La Pham Lan & Nguyen Thanh Binh

180

Table 3 The mean % shoots damaged by insect pests in the farmer’s plot and the IPM plot of the

demonstration orchard at Binh Phuoc province, Vietnam 2008

damaged /tree + SD

Friedman two–way ANOVA

Tea mosquito

bugs

2

= 0.400; df = 1; P

= 0.527

2

= 0.400; df = 1; P

= 0.527

2

= 0.111; df = 1; P

= 0.739

2

= 0.111; df = 1; P

= 0.739

The fruit-nut

borer*

P = 0.018

P = 0.933

*, Mann-Whitney U test is used

During the cashew dormant or leaf flush period

(April to July), the damage on flushing shoots

by tea mosquito bugs, shoot borers and leaf

miners was significantly lower in the IPM plot

than in the farmer’s plot However, the average level of shoots with aphids was more in the IPM plot than in the farmer’s plot (Table 4)

Table 4 The mean % shoots damaged by insect pests in the farmer’s plot and the IPM plot during the

tree dormancy or leaf flush period at Binh Phuoc province, Vietnam

damaged /tree + SD

Friedman two–way ANOVA

Tea mosquito

bugs

2

= 8.000; df = 1; P

= 0.005

2

= 8.000; df = 1; P

= 0.005

2

= 4.500; df = 1; P

= 0.034

2

= 8.000; df = 1; P

= 0.005

3.3.2 Hung Loc Centre orchard

Based on regular monitoring, the main insect

pests in this orchard are tea mosquito bugs,

leaf rollers, leaf miners, aphids and branch

borers The minor pests are shoot borers and mealy bugs The mean damage level on cashew flowers and young nuts by each of these pests was similar between the farmer’s plot and the IPM plot (Table 5)

shoots

Mealy bug damage on nuts

Weaver ants farm mealy bugs

Table 5 The mean % shoots damaged by insect pests in the farmer’s plot and the IPM plot of the

demonstration orchard at Hong Loc Centre, Dong Nai province, Vietnam 2008

damaged /tree + SD

Friedman two–way ANOVA Rank sum Statistic Tea mosquito

bugs

2

= 3.000; df = 1; P = 0.083

1; P = 0.135

2

= 0.333; df = 1; P = 0.564

2

= 2.000; df = 1; P = 0.157

1; P = 0.088

2

= 1.000; df = 1; P = 0.317

*, Mann-Whitney U test is used

The average number of nuts per tree were

similar between the farmer’s plot and the IPM

plot (P = 0.206; Table 6) The nuts were

cleaner and shinier in the IPM plot than in the

farmer’s plot

In the crop season 2008-2009, the

demonstration orchard at Hung Loc Centre of

the IAS has also been successfully completed

The weaver ant abundance was over 50% from

November 2008 to May 2009, the ant

populations were stable during the period of

cashew flowering and fruiting (January –

March) Regular monitoring showed that the

main insect pests are tea mosquito bugs, the

shoot borers, leaf rollers, leaf miners, mealy bugs and aphids The mean damage level on cashew flushing shoots, flowers or young nuts

by shoot borers, leaf rollers and leaf miners was similar between the farmer’s plot and the IPM plot Although tea mosquito damage was higher in the IPM plot than in farmer’s plot, the damage caused by tea mosquito bugs was <

5 %, which is lower than the control threshold determined by Peng et al (1997) The damage caused by mealy bugs and aphids was higher

in the IPM plot than in the farmer’s plot, but the average damage was <1% and <2% for mealy bugs and aphids respectively (Table 7)

Table 6 The number of cashew nuts per half canopy in the farmer’s plot and the IPM plot of the

demonstration orchard at Hung Loc Centre, Dong Nai, Vietnam 2008

(No + SD)

Rank sum

Friedman two–way ANOVA Xr2 = 1.600; df = 1; P = 0.206

Keith Christian, Renkang Peng, La Pham Lan & Nguyen Thanh Binh

182

Table 7 The mean % shoots damaged by insect pests in the farmer’s plot and the IPM plot of the

demonstration orchard at Hong Loc Centre, February 2008 – May 2009, Dong Nai province, Vietnam

damaged /tree + SD

Friedman two–way ANOVA Rank sum Statistic Tea mosquito

bugs

2

= 4.500; df = 1; P = 0.034

2

= 1.000; df = 1; P = 0.317

2

= 0.333; df = 1; P = 0.564

2

= 1.000; df = 1; P = 0.317

2

= 4.000; df = 1; P = 0.046

2

= 13.000; df = 1; P < 0.001

The average yield of cashew nuts per tree were

similar between the IPM plot and the farmer’s

plot (Table 8), but the nuts were cleaner and

shinier in the IPM plot than in the farmer’s plot

Table 8 The average yield of cashew nuts per tree in the farmer’s plot and the IPM plot of the

demonstration orchard at Hong Loc Centre, 2009 Dong Nai, Vietnam

(kg /tree + SD)

Rank sum

2

= 0.111; df = 1; P = 0.739

3.3.3 Trang Bom orchard

In Dong Nai demonstration orchard, the third

year experiment (crop season 2008-2009) has

been successfully completed After the ghost

ant was identified as the major factor to be

responsible for the failure of the main insect

pest control by weaver ants in the first and the

second year (Peng et al 2008d), to avoid a

strong competition between ghost ants and

weaver ants, existing weaver ants colonies on

the orchard boundary were used, together with

the management of boundary trees This

method was successfully to keep weaver ant

populations high and stable on cashew trees

The weaver ant abundance was over 60% from

November 2008 to May 2009, and the ant

populations were stable during the period of

cashew flowering and fruiting

Regular field observations showed that, in

contrary to the results of the previous two

years (Peng et al., 2008d), weaver ants

behaved normally, and they were active to

forage on flushing shoots, flowers and developing nuts No competition for food between weaver ants and ghost ants was observed The average number of flushing shoots and flowers was similar between the IPM plot and the farmer’s plot

The main insect pests in this orchard are tea mosquito bugs, the shoot borer, leaf rollers, leaf miners, mealy bugs and aphids (Table 9) The mean damage level on cashew flowers or young nuts by each of these pests was similar between the farmer’s plot and the IPM plot, with the exception of aphids that the damage level was higher in the IPM plot than in the farmer’s plot However, the average aphid damage was < 2% (Table 9)

The average yield of cashew nuts per tree were higher in the IPM plot than in the farmer’s plot (Table 10) Also, the nuts were cleaner and shinier in the IPM plot than in the farmer’s plot

Table 9 The mean % shoots damaged by insect pests in the farmer’s plot and the IPM plot of the

demonstration orchard at Mr Bi’s orchard, 10 November 2008 – 10 April 2009, Dong Nai province, Vietnam

damaged /tree + SD

Friedman two–way ANOVA Rank sum Statistic Tea mosquito

bugs

2

= 3.000; df = 1; P = 0.083

2

= 1.000; df = 1; P = 0.999

2

= 1.000; df = 1; P = 0.317

2

= 1.000; df = 1; P = 0.999

2

= 2.000; df = 1; P = 0.157

2

= 10.000; df = 1; P = 0.002

Table 10 The average yield of cashew nuts per tree in the farmer’s plot and the IPM plot of the

demonstration orchard at Mr Bi’s orchard, 2009 Dong Nai, Vietnam

P = 0.042

3.4 Development of an IPM cashew

curriculum and an IPM cashew photo book

The cashew curriculum has been developed

based on long-term field experiments and field

surveys in major cashew growing provinces

(Peng et al., 2008d) It is entitled “The

integrated cashew improvement (ICI) program

using weaver ants as a major component

-Manual for ICI program trainers and extension

officers in Vietnam” As planned, the manual

includes up-to-date information about cashew

botany, breeding, culture practice, diseases and

their control, insect pests and their damage,

natural enemies, integrated pest control, the

role of weaver ants, weaver ant keeping,

cashew harvest, a checklist of the ICI program

at different growing periods, and four appendices of guidelines for TOT and FFS training and for monitoring pest damages and

Keith Christian, Renkang Peng, La Pham Lan & Nguyen Thanh Binh

184

weaver ant abundance (Peng et al., 2008a)

This book was published in 500 copies

An ICI cashew photo book has also been

developed based on long-term field

experiments, field surveys and laboratory

rearing (Peng et al., 2008d) The ICI photo

book covers cashew variety selection,

advanced farming practice, major diseases,

major insect pests, the main natural enemies,

the integrated pest control methods, role of

weaver ants, weaver ant keeping techniques,

and the summary of the ICI programme (Peng

et al., 2008b) This book was published in

3000 copies

4 Conclusions and recommendations

Total of 113 TOT trainers have graduated from

our TOT training, and they are very competent

in FFS training These TOT trainers have

successfully conducted 98 FFSs in their local

regions, resulting in a total of 2,448 ICI

program farmers with improved knowledge

and farming skills

An ICI manual for TOT trainers and extension

officers in Vietnam and an ICI photo book for

cashew growers in Vietnam has been

developed and used by our TOT trainers in the

FFS training These manual were published in

500 and 3000 copies, respectively

After the FFS training, the percentage of

farmers who used insecticides, reduced to

24% The current level (67%) of farmers using

insecticides is expected to decrease further

when farmers get more and more experience

using weaver ants 92% of the farmers

demonstrated a full understanding of when and

how to properly use insecticides in their

orchards

Over 95% of farmers were happy with the FFS

training programs, with the training methods,

and with the results of demonstration orchards

There was high demand for the FFS training of

the ICI program by cashew smallholders who

have not been trained because of the positive

impact of the FFS farmers

Reference

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of study on the cashew pests in Binh Phuoc Province Paper presented at the Workshop on Plant protection serving to the policy of cultivation structure shifting in Central Highland and Southern Region Vung Tau, 24-25 June 2003.

Nguyen Thi Thu Cuc 1999 Research on the

smaragdina) on citrus fruit quality In: Van

Mele Paul and Nguyen Van Huynh (Eds)

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Belgium IPM in Fruit Production Project CanTho, Vietnam, 1999.

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Insect pests and diseases of cashew trees, populations dynamics, and some methods to control Final report of the project KN

06.04.NN.

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– Feasibility study of the utilization of red ants

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Guinea, August 1999, pp46.

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Second 6-monthly report to CARD Charles

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Agricultural Science for South Vietnam,

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15 Peng, R.K., Christian, K and Lan, L.P 2007b.

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Darwin University, Australia and Institute of

Agricultural Science for South Vietnam,

Vietnam, 7 September 2007, pp30.

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“Integrated cashew improvement program

using weaver ants as a major component -Manual for ICI program trainers and extension

University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam October 2008, pp89.

17 Peng, R.K., Christian, K., Lan, L.P and Binh,

N.T 2008b Cashew nut ICI curriculum II

“Integrated cashew improvement program using weaver ants as a major component – ICI Photo Book for cashew growers in Vietnam” Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam October 2008, pp69.

18 Peng, R.K., Christian, K and Lan, L.P 2008c.

Competency evaluation report to CARD Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam, December 2008, pp11.

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CARD Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam, 31 July 2008, pp28.

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Fourth 6-monthly report to CARD Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam, 28 February 2008, pp22.

21 Peng, R.K., Christian, K and Lan, L.P 2008f.

Fifth 6-monthly report to CARD Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam, Vietnam, 7 November 2008, pp28.

22 Peng, R.K., Christian, K and Lan, L.P 2009 Project validation report to CARD Charles Darwin University, Australia and Institute of Agricultural Science for South Vietnam,