Ministry of Agriculture & Rural Development CARD Project Progress Report

029/05/VIE
Implementation of the IPM program using
weaver ants as a major component for
cashewgrowers in Vietnam

MS2: Baseline Survey

Professor Dr. Pham Van Bien
Institute of Agricultural Science of South Vietnam
Dr Keith Christian and Dr Renkang Peng
Charles Darwin University
28 August 2006

1
Summary


Insecticides and fungicides were used by 83% and 56% of farmers respectively. The
mean frequency was 2.5 times (ranging from 1 to 6 times) per year for insecticides,
and 2.2 times (ranging from 1 to 4 times) per year for fungicides. It was found that
most farmers did not use pesticides properly.

With regard to other farming practices, the majority of farmers controlled
weeds either by using herbicides or by physical cutting. Pruning was also practiced by
most farmers, but the way they did it was not appropriate in most orchards. Mulching
and irrigation were generally not practiced.

Pesticide spray has already caused health problems in farmers and their
animals, and problems with the environment. This project will focus on this issue to
improve farmers’ health and the environment.
Farmers’ knowledge about the insect pests and diseases and their natural
enemies in their own cashew orchards is poor.
Most orchards had weaver ants, but their populations were very low due to
insecticide application. Most farmers (92%) were familiar with weaver ants, and 50%

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of them regarded the ants as beneficial. Based on these data, extensive and intensive
training about the biology of the ant is crucial for this project.
All the data obtained in this survey will be used for a comparison between
‘before’ and ‘after’ the implementation of this cashew IPM project.

1. Farmers’ opinion towards the cashew IPM program using weaver ants as
a major component

The baseline survey was conducted by TOT trainees in their own provinces using a
standard questionnaire (Appendix 1), so that the TOT trainees were aware of the
major problems cashew smallholders have in cashew production and what problems

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140
160
180
200
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145 70 10.4 + 5.0
Women only 16 8 10.7 + 7.0
Total 206 100

3. Current cashew farming status

Based on this baseline survey, the majority of cashew growers were small holders,
having about 2 ha of orchards with the average tree age being 6 years (for grafted
materials) and 12 years (for trees produced from seeds) (Table 3). Cashew nut yield
was about 1400 kg/ha in 2005 and 1000 kg/ha in 2006 (Table 3). Cashew apples were
generally wasted: only 5% of farmers used apples either for sale or for their own
consumption.

Table 3. Orchard size, tree age and average yield in 2005 and 2006.

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Yield (kg/ha)
Tree origin
in orchards
Orchard
size (ha)
Tree age
(years)
2005 2006
No. of
orchards
Graft 1.6 + 1.6 6.1 + 2.9 1388 + 602 1062 + 516 46
Seed 2.1 + 1.6 12.1 + 4.4 1500 + 833 1056 + 707 124

Traditionally, cashew growers in Vietnam did not use fertilizers, insecticides or

Type No. of orchards No. of times /year Period of use
Insecticides 171 2.5 + 1.3 Pre-flowering,
flowering and nut
setting
Fungicides 116 2.2 + 1.0 Flowering + nut
setting

Table 6. Comparison of cashew nut yields between orchards with insecticide spray
and those without insecticide spray.
Mean yield + SD
(kg/ha)
No. of
orchards
Tree
age
(years)
Use of
fertilizers
Use of
fungicides
Use of
insecticides
2005 2006
10 8 - 11 No No No 955 + 422 710 + 690
6 8 - 12 No No Yes (once
a year)
927 + 629 583 + 343 5

poison symptoms to you or to your animals during or after the pesticide spray?’, only
28 (20%) farmers said no side effect occurred, and these farmers either used machine
sprayers or wore protected clothing. However, 109 (80%) farmers experienced
various kinds of poison symptoms during or after the insecticide operations, and these
included skin irritation, headache, vomiting, breathing difficulty, unconsciousness,
sneezing, loss of appetite, dizziness, chest pains and/or tiredness. Most of these
farmers used small back-pack sprayers without suitable protective clothing. Apart
from this, some farmers mentioned that their animals, such as chicken and ducks,
were also affected.

When farmers were asked whether pesticide sprays cause environmental problems, 17
(8%) out of 198 farmers who addressed this question said “no effect”, but 181 (92%)
farmers said that pesticide spray had already caused adverse effects on the
environment, and this included pollution to water, soil and air, reduction of beneficial
insects, more frequent pest outbreaks, effect on farm animals and on their own health.

When farmers were asked whether they would continue to use pesticides, 81 (40%)
out of 202 farmers who answered this question said they would stop using pesticides.
The remaining 121 (60%) farmers expressed a complicated feeling that they do not
want to use pesticides, but they feel they have to because of so many insect pest
problems. Our project will concentrate on this issue to improve farmers’ health and
environmental quality. 6
5. Farmers’ knowledge of cashew insect pests and diseases and their natural
enemies

There were 182 farmers who addressed this issue. For insect pests and diseases, there
were 135 (74%) farmers who could recognise only one insect pest or disease, 36

crucial, and that the demonstration orchards with established weaver ant colonies will
provide farmers with a full picture of how the ants can benefit them.

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