Collaboration for Agriculture and Rural Development
(CARD)
Program
176
I
NTEGRATED
P
EST
M
ANAGEMENT
USING WEAVER ANTS
AS A
MAJOR COMPONENT FOR CASHEW
Project title:
Implementation of the IPM program using weaver ants as a m
ajor component for
cashew growers in Vietnam
Project c
ode
:
CARD
029/05/VIE
Author(s):
Prof.
Keith Christian
1
,
Dr.
Renkang Peng
1
,

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.
D
emonstration 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
-
ho
lders 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.
Keith Christian, Renkang Peng, La Pham Lan & Nguyen Thanh Binh
177
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 ferti

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
t
o conduct FFSs in their local region, (2) to

Phuoc province, and the other at the Hung Loc
Agricultural Research Center belonging to IAS
located i
n 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
oth
er 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 or
chard 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)

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 proporti
on of farmers using
insecticides before the FFS training, 24%
fewer farmers used insecticides after the FFS

square statistics
χ
2
= 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
Yes
152
147
299
No
44
49
93
Total
196
196
392
Pearson Chi
-

enemies, and 100% of the farmers knew
weaver ants very w
ell.
With regard to the reduction of insecticide use,
91% of the farmers used insecticides before the
FFS training, but after the FFS training, only
CARD 029/05 VIE
–
IPM for cashew using weaver ants
179
67% of the farmers used insecticides, resulting
in a 24% reduction (Peng et al., 2009). This
was because i
nsect 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
mo
re 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

), shoot borers
(
Alcidodes
sp.), leaf miners (
Acrocercops
syngramma
), aphids, the apple
-
nut borer
(
Nephopteryx
sp), leaf rollers and branc
h
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 fa
rmer’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).

Tea mosquito
bugs
Farmer
6.5
+
3.8
14.0
X
r
2
= 0.400; df = 1; P
= 0.527
IPM
6.7
+
3.2
16.0
Shoot borers
Farmer
8.3
+
7.0
14.0
X
r
2
= 0.400; df =
1; P
= 0.527
IPM

= 0.739
IPM
12.4
+
11.8
15.5
The fruit
-
nut
borer*
Farmer
0.11
+
0.69
5
7608.0
U = 29405.0; df = 1;
P = 0.018
IPM
0.01
+
0.15
56395.0
Leaf rollers*
Farmer
0.4
+
1.2
56575.5
U = 28372.5; df = 1;

way ANOVA
Rank sum
Statistic
Tea mosquito
bugs
Farmer
6.5
+
11.2
16.0
X
r
2
= 8.000; df = 1; P
= 0.005
IPM
2.4
+
4.3
8.0
Shoot borers
Farmer
5.0
+
2.0
16.0
X
r
2
= 8.000; df = 1; P

r
2
= 8.000; df = 1; P
= 0.005
IPM
13.3
+
9.6
16.0
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).
CARD 029/05 VIE
–
IPM for cashew using weaver ants
181
Brown aph
ids
Damage on
shoots
Mealy bug
damage on nuts

2.49
+
3.40
9
The shoot borer*
Farmer
0.64
+
1.79
5273.5
U = 27
88.5; df =
1; P = 0.135
IPM
0.26
+
1.06
5166.5
Leaf rollers
Farmer
3.13
+
3.85
7
X
r
2
= 0.333; df =
1; P = 0.564
IPM

1.96
+
5.49
5659.5
Aphids
Farmer
0.75
+
2.47
6.5
X
r
2
= 1.000; df =
1; P = 0.317
IPM
1.96
+
4.33
8.5
*, 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

demonstration orchard at Hung Loc Centre, Dong Nai, Viet
nam. 2008.
Plot (Treatment)
Number of nuts per tree
(No.
+
SD)
Rank sum
Farmer (use insecticides)
179.2
+
104.7
17
IPM (use weaver ants only)
177.9
+
143.9
13
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 i
nsect 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.

Farmer
1.51
+
3.84
18.5
X
r
2
= 1.000; df =
1; P = 0.317
IPM
1.95
+
4.72
20.5
Leaf rollers
Farmer
3.25
+
7.19
19.0
X
r
2
= 0.333; df =
1; P = 0.5
64
IPM
4.08
+

0.34
+
2.37
21.5
Aphids
Farmer
0.18
+
1.17
17.5
X
r
2
= 13.00
0; df =
1; P < 0.001
IPM
1.75
+
4.36
30.5
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 aver
age 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.

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
t
he 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
po
pulations 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 fl
ushing 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 or

+
SD
Friedman two
–
way ANOVA
Rank sum
Statistic
Tea mosquito
bugs
Farmer
3.70
+
6.09
18.0
X
r
2
= 3.000; df =
1; P = 0.083
IPM
2.42
+
3.97
15.0
The shoot borer
Farmer
1.37
+
4.07
16.5

4.33
16.5
X
r
2
= 1.000; df =
1; P = 0.999
IPM
1.46
+
3.39
16.5
Mealy
bugs
Farmer
0.01
+
0.15
15.5
X
r
2
= 2.000; df =
1; P = 0.157
IPM
0.09
+
0.55
17.5
Aphids

t =
-
2.068; df = 75;
P =
0.042
IPM (use weaver ants only)
14.3
+
2.0
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 prov
inces
(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

s
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 whe
n 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.

sma
ragdina
) on citrus fruit quality.
In
: Van
Mele Paul and Nguyen Van Huynh (Eds)
Proceedings of the 2
nd
symposium on Fruit
production in the Mekong Delta focusing on
integrated pest management
. Vietnamese
–
Belgium IPM in Fruit Production Project.
CanTho, Vi
etnam, 1999.
3.
Davis, Kristin. 1999.
Cashew
. ECHO
Technical Note. http://
www.echonet.org/
.
4.
Lan, L.P., H.X. Quang, V.T.T. Hoan, N.V.
Quoc, N.M. Hung and N.P.D. Huyen. 2002.
Insect pests and diseases of cashew trees,
po
pulations dynamics, and some methods to
contro

Guinea, August 1999, pp46.
7.
Peng, R.K., 2001.
The contro
l of cashew
insect pests in cashew plantations and small
holder plantings using red ants,
Oecophylla
smaragdina
.
–
The second stage of
implementation (Final). A report to the
Livestock Development Corporation, Port
Moresby, Papua New Guinea, March, 2001,
p
p33.
8.
Peng, R.K., 2002. Use of weaver ants, to
control the major cashew insect pests,
Helopeltis
and
Pseudotheraptus
, in the central
Nursery and smallholder orchards in Maganja
Da Costa, Zambezia Province, Mozambique.
A consultant report to ADRA Cashew
Ref
orestation Project, Mozambique,
September, 2002.

Development Corporation, Canberra,
Australia.
11.
Peng, R.K., Christian, K. and Gibb, K. 2004
.
Implementing ant technology in commercial
cashew plantations. RIRDC Publication No.
W04/088, May 2004, ISSN 1440
-
6845.
12.
Peng, R.K
., Christian, K., Bien, P.V. and Lan,
L.P. 2006
a
.
Baseline survey report to CARD.
Charles Darwin University, Australia and
Institute of Agricultural Science for South
Vietnam, Vietnam, 28 August 2006, pp12.
13.
Peng, R.K., Christian, K. and Lan, L.P. 2006
b
.
Fi
rst 6
-
monthly report to CARD. Charles
Darwin University, Australia and Institute of
Agricultural Science for South Vietnam,

using weaver ants as a major component
-
Manual for ICI program trainers and
extension
officers in Vietnam”. Charles Darwin
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. 2008
b
.
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., Chris
tian, K. and Lan, L.P.
2008
c
.
Competency evaluation report to CARD.

Fifth 6
-
monthly report to CARD. Charles
Darwin University, Australia and Institute of
Agricultural Sc
ience for South Vietnam,
Vietnam, 7 November 2008, pp28.
22.
Peng, R.K., Ch
ristian, K. and Lan, L.P. 2009.
Project validation report to CARD. Charles
Darwin University, Australia and Institute of
Agricultural Science for South Vietnam,
Vietnam, April 2009, pp1
6.