Coconut Research Institute Repository

Everard, J.M.D.T.

Use of molecular markers for breeding of the coconut palm Cocos nucifera

Vidhana Arachchi, L.P.

Liyanage, M.de.S.

Role of Gliricidia sepium on physical improvement of soil

Liyanage, M. De S.

U S E S A N D M A N A G E M E N T O F N I T R O G E N 
F I X I N G T R E E S I N 
C O C O N U T P L A N T A T I O N S 
Low productivity and poor returns 
from a unit of coconut land coupled with price 
instability of the coconut crop have threatened 
the sustainability of coconut plantations in Sri 
Lanka. Over the past three decades, coconut-
based farming systems 
have been introduced by 
the CRI, for the purpose 
of increasing land produc­
tivity and generating ad­
ditional income to the co­
conut farmer. 
M de S Liyanage 
Coconut Research Institute of Sri Lanka 
erate rainfall to increase productivity and ac­
crue several benefits to the farmer. 
On fertile soils 
with favourable climate, 
farmers are encouraged to 
grow high value cash 
crops with a ready market 
such as Pineapple, Ba­
nana, Pepper, Ginger, Be­
tel, Cinnamon etc. Nitro­
gen Fixing Tree (NFT) 
species have been intro­
duced to areas where 
these cash crops will not 
perform well especially on degraded marginal 
land with less favourable climate such as those 
in the intermediate and dry zone.(mainly land 
suitability classes 4 and 5) 
Since 1987, CRI has attempt^ to grow 
several nitrogen fixing trees (NFT s) such as 
Gliricidia sepium, Calliandra callothyrsus, 
Leucaena leucocephala and Acacia 
auriculiformis, with the main objective of uti­
lizing such marginal coconut land with mod-
Figure 1.Gliricidia cultivated in between coconut rows 
Factors to be considered in selecting NFT s 
* Compatibility with coconut 
* Tolerance to partial shade 
* Ability to grow on degraded soils 
* Optimum biomass production under cocon­
ut shade 
* Ability to withstand repeated pruning 
* Good coppicing ability 
* Use minimum external inputs 
(eg. fertilizer, pesticides) 
4 
* Compatibility with coconut 
The effect of fast growing tree species 
on coconut yield is an important aspect to be 
considered in promoting their adoption in co­
conut plantations. Data collected over five 
years have revealed that despite non applica­
tion of fertilizer and water to NFT s, there was 
no detrimental effect on the palm, compared 
to control blocks. Among species, all except 
Leucaena showed an improvement in the yield 
of coconut in the range of 15-20%. 
* Tolerance to partial shade 
mass productivity in NFT s could be achieved 
by pruning trees 1.0 m above ground at 3-4 
monthly intervals. For instance.gliricidia is 
capable of producing 10-15 mt of fresh 
loppings per year from one hectare of coco­
nut land. 
* Ability to grow on degraded land 
NFT species have established well and 
continue to produce satisfactory biomass with­
out fertilizer on Andigama soil series which is 
considered marginal for coconut due to poor 
physical characteristics of the soil. 
It has been 
shown that among 
NFT s the least reduc­
tion of biomass yield 
under reduced light 
occurred in Gliricidia 
(23%) followed by 
Calliandra whereas 
biomass of Leucaena 
was reduced most 
(56%) by low light, 
suggesting that it is 
less shade tolerant. Of 
all NFT species, 
Gliricidia has shown 
to be the most compat­
ible species that could 
be grown in associa­
tion with coconut. Figure 2.Use of Gliricidia leaves as green manure 
* Optimum biomass production under co­
conut shade 
Optimum biomass production can be 
achieved by tree management. Frequency and 
height of pruning are important aspects in tree 
management. 
Experience has shown that highest bio-
* Use of minimum external inputs 
This is a clear advantage of NFT s as 
other crops will not perform well without the 
application of fertilizer and pesticides. These 
trees have the ability to meet their own nutri­
ent requirement by foraging through the soil 
profile, biological nitrogen fixation and they 
5 
are practically free of pests and diseases. 
* Ability to withstand repeated pruning 
Despite NFT species have been sub­
jected to pruning 3-4 times a year and this pro­
cess has been re­
peated for five 
c o n s e c u t i v e 
years,trees con­
tinue to perform 
well and remain 
productive over 
the years. 
requirement of the coconut palm, thus provid­
ing about 40% saving on the cost of fertilizer. 
It will also provide a regular supply of micro-
nutrients to the palm. 
* Coppicing 
ability 
The abil­
ity of NFT s to 
produce new 
shoots after each 
pruning is re­
ferred to as 
coppicing ability. 
All NFT s have 
shown their ability to produce coppice shoots 
after pruning. Among NFT species, Gliricidia, 
Calliandra and Acacia have shown better 
coppicing ability. 
ROLE OF NFT' S IN COCONUT PLAN­
TATIONS 
* Use of fresh biomass as green manure 
Figure 3.Gliricidia foliage as animal fodder 
* Use of fresh biomass as mulch 
Of the NFTs. prunings of Acacia fol­
lowed by Calliandra have shown a greater 
promise to serve as a surface mulch. With all 
species, mulching has shown a better effect 
against bare soil, in terms of moisture conser­
vation ability, soil temperature regulation, and 
weed suppression. 
Of the NFT species, Gliricidia and Leucaena 
foliage is particularly rich in nitrogen. It has 
been shown that application of 35 kg fresh 
Gliricidia loppings could satisfy the total re­
quirement of N and at least 20%' of P and K 
* Use of fresh biomass as animal fodder 
Mixing of poor quality grass or rice 
straw with Gliricidia and Leucaena foliage 
up to about 30% of the total feed will provide 
a balanced ratio for livestock, especially dur-
6 
ing the dry period. Feeding with high protein 
supplements has given rise to improved intake, 
better digestibility and weight gains of rumi­
nant livestock. Acacia leaf is commonly fed 
to goats. 
* Restore and improve soil fertility 
NFT species have a special ability to 
grow on marginal lands and improve soil 
physical, chemical and biological properties, 
there by improving the productivity of soil and 
facilitating better growth and yield of coco­
nut palms. 
* UseofNFT's as temporary shade 
In new plantations, species like Gliri­
cidia and Leucaena have been grown together 
with coconut seedlings to provide temporary 
shade.especially in dry areas to provide a 
favourable microclimate for initial establish­
ment and growth up to about 3 years from 
planting. 
* Use of NFT's as live support 
Of the NFT's Gliricidia is widely used 
as a live support for Pepper and Vanilla grown 
together with coconut. Application of Glricidia 
loppings arround Pepper could reduce the fer­
tilizer requirement of Pepper by about 50%. 
Considering the easy management and 
the potential use of NFT's, it is profitable to 
grow them, especially on marginal coconut 
lands. 
/ i 
Specialist Assistance to Develop your Plantation 
The Coconut Research Institute implements programme known as "Persuasive 
Extension Programme" to assist coconut growers to develop their plantations with the 
adoption of new technology. In this programme a group of scientists and extensionists 
of the Institute meet land owners in their plantations and draw up suitable develop­
ment plans in consultation with land owners. In this exercise land owners have an 
opportunity to discuss their problems and limitations and decide on future development 
activities. Officers from this institute continue to assist them in the implementation of 
the proposed development plan and monitor the progress. This is a valuable opportu­
nity for growers who wish to improve the productivity of their plantations. 
If you wish to register to obtain this service, please write to Director, Coconut 
Research Institute, Lunuwila, Sri Lanka. 
7 


Uses and management of nitrogen fixing trees in coconut plantations

Vidana Arachchi, L.P.

M I N I M I Z I N G D R O U G H T D A M A G E O N 
C O C O N U T I N M A J O R S O I L T Y P E S 
Prolonged drought conditions bring 
about moisture stress to coconut palm caus­
ing button nut fall and immature nut fall re­
sulting in about 60% loss of potential coco­
nut production. The damage due to drought in 
coconut could be minimized with the applica­
tion of proper management practices. Effec­
tive and efficient moisture conservation prac­
tices or irrigation techniques could be devel­
oped only through scientifically sound basis. 
Therefore better knowledge of the soil physi­
cal characters, coconut root system, and mois­
ture in the root-soil interface are essential to 
formulate proper management practices. 
Water retention in different soils 
Table 1 shows the ability and the du­
ration of water retention in major coconut soils 
of the coconut triangle during dry periods. Re­
sults indicated that various soil types have dif­
ferent capacities to retain rain water during the 
hydrological cycle for example, the highest 
water retention was observed in the 
Melsiripura and Ambakele soil series. The re­
sult revealed that these soil types have the ca­
pability to retain more water for a longer pe­
riod in the root zone of coconut. High water 
retention was also indicated in soil series of 
Madampe, Pallama, Katunayake, Welipalassa, 
Borupan, Gambura, Mavillu and Wilpattu. 
Coconut palms in these soil series were not 
severely affected by the drought. However 
Boralu, Andigama, Sudu, Kalpitiya and 
Kuliyapitiya series have a low potential to 
retain rain water, for a short period (about 2 
weeks). Although water availability of 
Kalpitiya series is fairly low, the occurrence 
L P Vidana Arachchi 
Coconut Research Institute of Sri Lanka 
of a pure water lense at 1-2 m from the sur­
face in Kalpitiya area would compensate for 
less moisture retention in soil. In addition, 
sandy soils (eg. Sudu series, Kalpitiya) allow 
infiltration of water at a high rate leading to 
leaching of fertilizer beyond the coconut root 
zone. In contrast, compact soils tend to waste 
more rain water through surface runoff due to 
poor infiltration. Therefore, appropriate mois­
ture and fertilizer conservation measures have 
to be adopted to improve water holding ca­
pacity of both sandy and compacted clay loam 
soils. Such practices would minimize drought 
damage on coconut production to a greater 
extent. 
Coconut root system 
Effective root zone 
Root growth and proliferation of the 
coconut palm vary with the physical 
charateristies. Generally, coconut roots spread 
throughout the soil profile and experiments 
have shown that about 75% of the coconut root 
zone occurs within the depth of 20 to 80 cm 
vertically and about 5% of root mass is found 
beyond 100 cm depth. Nuetron probe studies 
have revealed that, on moderately deep sandy 
clay loam soils, only the moisture stored at 
the depth of 20-80 cm range is extractable by 
the palm. But in deep loamy soils, moisture 
stored up to 150 cm depth is extractable. The 
water extraction is at maximum about 1 m dis­
tance from the bole of the palm. 
In addition, absoption of water from 
13 
deeper layers by 5% of the root mass in deep 
loamy soils would be sufficient to a greater 
extent to meet the water requirements of 
the coconut palm, during dry periods. 
As immature roots are more active in 
absorption of water and nutrient than lignified 
mature roots, they need to be protected from 
drought damage. Therefore, proper moisture 
availability should be ensured in the root-zone 
for efficient nutrient and water uptake and their 
survival. 
Absoption zone of coconut roots 
Coconut roots in contrast to other crops 
do not produce root hairs that absorb water 
and nutrients. The absoption zone of the co­
conut roots is the cream coloured region lo­
cated just behind the root cap through which 
water and nutrients are taken up by the palm. 
During dry periods, immature 
absoption zone is badly damaged by heat, wa­
ter and soil physical stress. Cells of absorp­
tion zone of coconut roots in Andigama series 
(gravelly soil: suitability class 4) are severely 
damaged due to soil physical and water stress 
compared to Madampe series (sandy loamy 
soil; Class 1 ). Moreover, drought stress in­
duces coconut roots to re-produce more roots, 
but these roots become inactive very soon. 
Therefore, the drop in coconut yield 
due to drought could be (1) inefficient fertil­
izer absorption (2) thickening of coconut roots 
and (3) dehydration of immature roots. 
Precautions 
Studies on root characteristics under 
stress conditions have revealed the importance 
of soil moisture and conservation practices 
recommended by Coconut Research Institute. 
These practices are mulching, cover crop es­
tablishment, soil amelioration using organic 
manure, and husk/coir dust pits. Such prac­
tices help to conserve rain water in the soil. 
Irrigation techniques such as drip or basin ir­
rigation linked with moisture conservation 
practices can be successfully adopted in se­
vere dry periods to remedy the drought dam­
age of coconut. 
Studies carried out on soil moisture 
status have shown that soil series of Andigama, 
Sudu, Kuliyapitiya, Maho and Boralu need ir­
rigation along with moisture conservation 
practices to remedy drought damage of coco­
nut during severe dry periods. In contrust, soils 
with high water retention capacity, moisture 
conservation practices only would be sufficient 
to minimize drought damage. Moisture con­
servation practices could also improve physi­
cal properties of soil.Especially the usage of 
husk and coir dust pits improve coconut root 
penetration in hardy soils such as gravels. This 
would further improve the aeration and nutri­
tional status of such soils. 
THEY SAY 
"I believe that coconut oil would become the new health oil in the next 
millenium." Monolaurin is among the world's "most kept secrets." 
— Dr. Jon J. Kabara, Emeritus 
Professor, Michgan State University 
Source: PCRDFNews cope. Volume Number 1, First Quarter 1998 
14 
Table 1 Major soil series in the coconut triangle, their extent, moisture 
retention capacity and duration. 
Agro Duration 
ecological of dry 
regions periods 
(days) 
1st 
2nd 
DL3 
75 135 
(Dry Low 
country 
region) 
JL1 
(Semi-wet 
Intermediate 75 75 
Low 
country 
region) 
JL3 
(Semi-dry 
Intermediate 75 120 
Low 
country 
regions) 
Soil series Acerage in 
the 
coconut 
triangle 
(Ac) 
Borupan . 13,200 
Gambura 8,700 
Wilpattu 9,840 
Mavillu 10,260 
Weliketiya 8,160 
Kalpitiya 8,240 
Kurunegal 157,840 
Kuliyapitiy 58,480 
Rathupasa 3,800 
Madampe 12,960 
Sudu 1,400 
Maho 37,120 
Wariyapola 102,160 
Andigama 71,660 
Ambakele 5,320 
Welipelessa 12,960 
Water Duration 
retention of water 
capacity retention 
(mm) (days) 
285 53 
260 48 
256 47 
238 44 
103 19 
53 10 
92.8 19 
56 11 
211.3 43 
186.3 38 
42 9 
105.8 22 
110.7 23 
66 14 
299.6 61 
199.1 41 
IM3 
(Semi-dry 
Intermediate 
Mid 
country 
region) 
WL3 
(Moderatel-y 
Wet Low 
country 
region) 
WL4 
(Moderately 
Wet Low 
country 
region) 
60 135 
Melsiripur-a 117,600 
75 30 Boralu 59,600 
Pallama 49,120 
75 30 Katunayake 5,340 
307.5 
55 
193.4 
166.3 
63 
12 
40 
35 


Minimizing drought damage on coconut in major soil types

Appuhamy, P.A.H.N.

r 
S T R E N G T H E N I N G C O O P E R A T I O N A M O N G 
C O C O N U T S M A L L H O L D E R S 
F O R G R E A T E R B E N E F I T S 
In Sri Lanka, coconut is predominantly 
a small holder's crop. Lands less than 20 acres 
are considered as small holdings. Although co­
conut is not the major family income source 
in the small holder sector, its contribution to 
their livelihood is of much importance. In 
marketing coconut, small holders are directly 
dependent on the village coconut dealers who 
act as middlemen in the market chain. Unlike 
in the estate sector, small holders do not have 
bargaining power for higher prices. The price 
offered by the village dealer is far below the 
actual price of coconut. Small holders, often 
obtain cash advances and loans for their ur­
gent requirements from village dealers. As a 
result, these coconut growers have firm com­
mitments to supply their coconuts regularly 
to the village dealer even at a lesser price. This 
type of exploitation is very common in rural 
areas where coconut is grown as the main crop. 
Under these circumstances, small holders are 
deprived of reasonable prices and also cost 
limitations on savings for their future finan­
cial needs. However, in some areas, small 
holders have organized themselves and formed 
societies for their own financial benefits 
through co-operative effort. The main aim of 
this paper is to discuss the structure and the 
performance of these coconut grower's orga­
nizations, so as to create an awareness among 
other small holders. 
The initial formation of these organi­
zations is a result of dedication and enthusi­
asm of few progressive coconut growers. The 
P.A.H. N I M A L A P P U H A M Y 
Coconut Research Institute of Sri Lanka 
objectives of these organizations are to in­
crease the income of small holders by ensur­
ing higher prices for coconut and also to as­
sist members in their financial needs. 
Each organization has its own area of 
operation which includes few villages. Coco­
nut growers in such areas are eligible for 
membership of the organization, which is man­
aged by a working committee. This comprises 
a Chairman, Secretary, Treasurer and three or 
four committtee members selected among the 
, members on an honorary basis. A grower 
should be able to supply a reasonable number 
of coconuts every two months if he has to be a 
member. The number of coconuts to be sup­
plied depends upon the level of production in 
the respective growers land. 
The organization employs a person to 
collect and transport nuts from members, and 
they are expected to supply good quality nuts 
and obtain a receipt from the person who col­
lect nuts. Every two months members are ex­
pected to attend these meetings, in order to 
get their entries updated in the record books. 
The total collection of nuts during the respec­
tive periods are presented at the auction. Due 
to competition among coconut dealers at the 
auction, coconuts fetch fairly attractive prices. 
The real value of coconut supplied by each 
member is deposited in their account for 
which an attractive interest is paid. 
41 
The validity period of such organiza­
tion is generally five years. Members are not 
allowed to draw money from their accounts 
until the entire five- year period is over. How­
ever, they are entitled to obtain loans in dis­
tress or to develop their coconut lands on easy 
terms and conditions. Members are also privi­
leged to repay the loan and interest by way of 
nuts, in addition to their normal supply. At 
the end of each year, whatever, extra income 
to the organization will be distributed among 
the membership depending on the number of 
nuts contributed by each member. 
Each organization has its own consti­
tution which is approved by the members at 
the Annual General Meeting. Each member 
is provided with a record book on which the 
constitution is printed. At each coconut auc­
tion, members are expected to update their ac­
counts in the record book. 
The success of these organizations de­
pend on the mutual understanding, trust and 
dedication among the members. According to 
the terms and conditions of these organiza­
tions, the following features could be ob­
served. 
1. At the beginning, each member should in­
dicate the number of coconut shares that they 
intend to possess. One share refers to 10 
coconuts. 
2. Minimum number of shares that one could 
possess is five and the maximum is hundred. 
3. Each member is bound to supply the agreed 
number of coconuts every two months. If one 
fails to supply the agreed number of coco 
nuts, he is expected to settle the balance at 
the next supply, along with extra nuts as a 
fine. 
4. Coconuts should be sold to the highest bid­
der at the auction held in every two months. 
5. The real value of coconut shares is added to 
the member's account at every two monthly 
period. The member is not allowed to draw 
money from the account until the full period 
(five years) is over. 
6.During dire financial requirements members 
have the option to raise loans, at a reasonable 
interest. 
These organizations are very active as 
members benefit financially and by various 
other means. Members being.coconut grow­
ers could arrange to obtain their inputs (fertil­
izer, seedlings.machinery) at reasonable costs 
through the organization. Under these circum­
stances, the extension organizations too find 
it convenient to provide efficient services. 
Hence, these cooperation organizations which 
emerged through the existing social 
structure,deserve encouragement and 
upliftment, to establish similar societies in 
other coconut growing areas for the benefit of 
the coconut grower. 
42 


Strengthening cooperation among coconut small holders for greater benefits

Coconut Research Institute

De S.Liyanage, M.

Jayasekera, C.

Report of the coconut research institute for 1996

Perera, B.S.V.J.

Tennakoon, N.A.

Changes in microbiological and chemical parameters in differenttypes of coconut soils after amended with cattle manure

Mapa, R.B.

Yapa, P.A.J.

Somapala, H.

Evaluation of land suitability for coconut production in relationto soil physical properties

Ranasinghe, C.S.

Taylor, G.

Mechanism for increased leaf growth in elevated CO2

Rajapakse, C.N.K.

P H E R O M O N E B A I T E D T R A P S : A P R O M I S I N G 
T O O L I N I N T E G R A T E D P E S T 
M A N A G E M E N T 
Many insects use chemicals called 
pheromones to communicate with other indi­
viduals of the same species. Various kinds of 
pheromones such as alarm pheromones, trail 
pheromones, sex pheromones and aggregation 
pheromones are produced by insects which 
function differently. Many members of co-
leoptera the largest insect order into which 
beetles and weevils belong produce aggrega­
tion pheromones. 
Aggregation pheromones which are 
produced by the male insect attract both sexes 
of that species to help aggregation. In red wee­
vils this pheromone signals the presence of an 
oviposition site and a food source. 
Insects are the dominant group of ani­
mals on earth. They have lived on the earth 
for about 350 million years, compared with 
less than 2 million years for human. Chemi­
cal communication in insects is highly devel­
oped. They can perceive and respond to re­
markably small quantities of chemicals. In­
sects generally perceive odours by means of 
specially adapted sensillae on the antennae. 
More often, insects use pheromones to com­
municate with other individuals of the same 
species. Most pheromones are produced by ec­
todermal glands secreting to the outside of the 
body. The members of Coleoptera produce 
male aggregation pheromones, which the male 
emits a scent to attract other members of both 
sexes resulting in forming aggregations. 
Scientists have studied the communi­
cation systems of insects and discovered the 
chemical structures of the pheromones. These 
pheromones could be synthesized in the labo-
C N K RAJAPAKSE 
Coconut Research Institute of Sri Lanka 
ratory and subsequently used in pest control 
programmes. 
It would be good news for coconut 
growers to be aware that red palm weevil and 
black beetle which are the most serious pests 
of coconut could be managed by trapping them 
using their aggregation pheromones. 44-me-
thyl-5 nonanol' commonly known as 
'ferrugineol' is an aggregation pheromone of 
the red palm weevil which is emitted by the 
male insect. Laboratory and field tests carried 
out at the Coconut Research Institute have 
proved that ferrugineol could be successfully 
used to trap both males and females of red 
palm weevil. Red palm weevil populations can 
be suppressed to a minimum level by instal­
lation of plastic bucket traps lured with 
ferrugineol in coconut plantations. 
Essentially, a pheromone trap consists of 4 
main components: 
1. plastic or a suitable container with a smooth 
surface. 
2. A dispenser to release the pheromone at 
a constant rate.Pheromone level should 
be clearly visible through the dispenser 
so that the growers could replace it 
when the pheromone is fully used. 
3. Mechanism to kill trapped weevils. 
4. Food component to simulate the natural 
sources of attraction such as fermenting 
sap of coconut palm. 
18 
Two types of traps lured with ferrugineol have 
been tested and found effective for red wee­
vil. 
1. Open bucket trap (Fig. 1) 
A 5 litre plastic bucket is suitable for 
this trap. Ferrugineol is in liquid form and is 
filled in either a sachet (50 x 50 x 0.12 mm) 
made out of 500 gauge polyethylene layflat 
tubing Or in a Polythene vial (20 x 15 x 2.0 
mm). Polythene sachet should be filled up to 
2 cm and sealed. These sachets release 0.96 
mg of the pheromone per hour under normal 
atmospheric conditions. The polythene vial 
can be fixed to the bucket as in Fig. 1. It has 
been proven the pheromone-food baited trap 
is more efficient than the trap baited with 
pheromone alone. These food material should 
be replaced at least fortnightly while the phero­
mone filled dispensers remain intact. The trap 
should be filled with a soap solution up to a 8 
cm level to kill the trapped weevils. Few holes 
should be made just above the level of soap 
solution to drain excess rain water. 
2. Plastic bucket with a funnel (Fig. 2) 
A funnel fixed plastic bucket (5 litre) 
is used for this type. Galvanized funnel is fit-
Pheromone container 
Holes to drain 
Inverted Funnel 
- 0 
-Neck of the funnel 
Pieces of sugar cane or 
coconut petioles 
Figure 1 : Plastic bucket with a funnel ~ 
with 200 pi of ferrugineol releases 0.08 mg 
per hour at the field temperature. The reduc­
tion of the level of the ferrugineol could be 
clearly visible in these slow release pheromone 
dispensers as ferrugineol permeates through 
the wall with time. The dispenser containing 
ferrugineol is hung on the brim of the bucket 
and to protect the pheromone from rain wa­
ter, a Small galvanized hood is fixed to the 
bucket just above the dispenser. Pealed pieces 
of coconut petioles or sugar cane stem cut­
tings can be kept in a small container which 
ted to the bucket opening and the tappered 
end of the funnel mouth should be 2 cm in 
diameter. Pheromone filled dispenser is fixed 
inside the bucket close to the funnel 
mouth.Adult red weevils attracted to the 
pheromone, slip through the funnel mouth into 
the bucket. Trapped weevils cannot escape 
through the funnel mouth as the size of the 
mouth is smaller than the wingspan of the 
weevil. Attractiveness of this trap could be 
improved by placing stem cuttings of sugar­
cane or pealed coconut petioles inside the 
19 
Plastic bucket 
A 
a 
•Rain cover 
•Pheromone container 
-Holes to drain 
•Soap solution 
Figure 2: Open bucket trap 
bucket. These food material should be treated 
with carbofuran or diazinon to kill the trapped 
weevils. 
Both types of pheromone traps should 
be hung on trunks of coconut palms at a height 
of 1.5 m from the ground level with 40 m dis­
tance between two traps. Comparatively more 
weevils are attracted to the traps hung in open 
areas than in shady areas. Red palm weevils 
can fly around 900 m hence, 12 traps per hect­
are is desirable. 
Pheromone traps for Black beetle 
Another aggregation pheromone, 
chemically known as 'ethyl-4-methyl 
octonoate' secreted by the male black beetle 
has also been identified and synthesized in the 
laboratories. Traps lured with this pheromone 
are being tested by the CRI at the moment. 
So far, two trap designs have shown promis­
ing results with a higher number of adult 
beetles of both sexes. Deep plastic contain­
ers, probably 11 plastic buckets are suitable 
for trapping black beetle. Simple open plas­
tic bucket lured with the pheromone buried in 
the ground near young palms and a similar 
trap fitted with metal cross vanes and kept on 
the ground beside palms caught very high 
number of beetles within a short period of 
time. 
Pheromone traps could be used to : 
1. Reduce Red weevil or Black beetle 
population in neglected coconut plan 
tations. 
2. Identify areas where weevil or beetle 
populations are high. 
3. Trap Red weevils emerging from untre­
ated infested palms or unattended 
rotten trunks and black beetles emerg 
ing from their breeding places. 
In coconut plantations heavily infested 
with red palm weevil, continuous trapping 
over several months significantly lower the 
incidence of reinfestations. However it is im­
portant to keep in mind that pheromone traps 
are not the ultimate solution to control these 
major pests of coconut. Pheromone based 
mass trapping should essentially be consid­
ered as one of the tools in integrated manage­
ment programmes of these pests. 
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Pheromone baited traps. a promising tool in integrated pest management

National Science Foundation of Sri Lanka

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