Mission 4: Watermelon at Takwa

Kastom Gaden Association
Planting Materials Network, Department of Agriculture and Livestock, and PestNet

Linking Farmers to Plant Protection Network
(Solomon Islands)

Project #1222 infoDev The World Bank

19 to 21 May 2004

Sydney
May 2004


Introduction

This is the report of the third workshop under the PestNet/KGA/DAL collaboration to test how rural email can assist farmers in remote areas of Solomon Islands. Following PRAs in the project area in October 2003, Takwa was selected by the Baetolau Farmers’ Network as the site of a watermelon workshop. Takwa and surrounding villages of Gwounasu, Nanadi and Hatodea are on the north coast of Malaita.

The aim of the workshop was for farmers to identify and prioritise watermelon pest problems and, together with KGA, DAL and PestNet, discuss options for control. Monitoring of the trials is to be carried out by the KGA/PestNet Community Field Officer and the DAL Field Officer stationed at Malu’u, with regular updates sent to PestNet moderators by email and to others in the network.

The workshop was held in a building belonging to the Chair of the BFN. Twenty-seven from 30 participants who applied to attend the workshop were present, and 11 additional participants also came. The SPC Extension Specialist Plant Protection Service, also attended.

The workshop
Opening remarks

After opening remarks of welcome by the Manager of the Kastom Gaden Association, and the Chair of the BFN, Mariano Lauga, Principle Agriculture Officer, DAL, provided a history of watermelon production in the area. It started in 1987 with a few families, and now there are more than 200. The aim was to increase family incomes, Up till 1993, workshops were held on agronomy, the use of pesticides, and, in collaboration with other Departments, book-keeping. At these workshops, both husbands and wives were encouraged to attend. More recently, newcomers are given the opportunity to work with more experienced growers for one or two cropping season to learn production techniques.

The technology is complex, and details were given on the use of mulch, manures, nursery composts, commercial fertilisers, pesticides, etc. There are two crops a year: the first is planted in February, the second in August. The latter is the main crop. The fields are about 50 m x 30 m.

A number of varieties have been tried over the years, with Empire 2 and Flower Mountain the most popular. Marketing is through outlets in Auki and Honiara and through a company called Didao, which previously sent ships to north Malaita to collect the crop. Now the ships come less often, due to problems associated with the ethnic tension.

Following the introduction to watermelon cultivation in the Takwa area, the PestNet Chair, Grahame Jackson, explained about email and the way that PestNet operates. This was followed by a discussion on the Network, which covered topics, such as costs (it is a free service), who in DAL are members of PestNet, how to send a message, what kind of advise will be received, and why the email station is at Silolo (and not at Takwa!), and the way that DAL/KGA representatives at Silolo and Malu’u can assist.

The farmers were asked to introduce themselves and to give their expectations of the workshop. A list of participants is given in Annex 1, and workshop agenda in Annex 2.
Defining the pest problems

Working in groups, the participants noted the problems that exist on watermelon in the area, providing as much detail as they knew on damage, cause and seasonality. Samples were collected from gardens to illustrate the pests and diseases. The problems were then ranked in order of importance.

The main problems identified were tiny ‘butterflies’ (actually moths), green caterpillars (probably larvae of the moths ), red ants, a yellow bug (Aulacophora pumpkin beetle) and fungus attacking vines and leaves. There was general agreement about the pests: that they were generally worse in the wet season, the fungus comes from the ground and rotten sticks, mulching increased fungal problems, and the red ants caused a leaf curl (actually caused by aphids). Control measures were handpicking and pesticides. Overall, the women were less knowledgeable about the pests and diseases of watermelon than the men.

Participants were then asked to rank the problems on a scale of 1 (least serious) to 5 (most serious).

Problems Grp 1 Grp 2 Grp 3 Grp 4 Total Rank
Fungus leaf spot 4 4 4.2 5 17.2 1
Tiny butterflies 3 5 2.1 5 17.1 2
Fungus vine 2.2 5 3.3 5 15.3 3
Small fruits and roots 5 3 3.1 4 15.1 4
Red ants 2 5 2.6 5 14.6 5
Large fruit rots 3 5 2.0 4 14.0 6
Green caterpillar 1 5 2.9 4 12.9 7
Yellow beetle 4 3 1.4 4 12.4 8
Grasshopper 2 4 1.5 3 10.5 9

The farmers produced seasonal calendars, and these showed a large variation between the groups in the number of sprays applied to the crops. Insecticide and fungicide was applied either once a week (one group) or once every two weeks (two groups) on a routine basis, except for one group, which said they applied the chemicals according to need.

The most frequently used insecticide is Orthene (acephate), although carbaryl is also used “in the event that Orthene fails to control a pest”. Both these chemicals are used shortly after transplanting, presumably against the pumpkin beetles, and then weekly, fortnightly or as required. A majority of farmers also used ICON, a synthetic pyrethroid-containing product for malaria control. Bravo (chlorothalonil) is the fungicide mostly commonly used, although copper oxychloride is known. Fungicides are applied in the nursery as well as in the field.
Control strategies

Insect and disease control

Wilco Liebregts talked to the farmers about the insect pests that they had mentioned in the group sessions and seen in the field during a practical session. The farmers were introduced to biological control concepts, and many examples were provided from the samples collected. It is likely that the insecticides, which are used frequently, are killing natural enemies as well as the pests . They are also killing the bees. Alternative products are needed, and BT (Bacillus thuringiensis) would be a suitable choice, if available. The insects collected in the area are given in Annex 3.

Grahame Jackson talked about the fungal disease that is destroying the leaves of watermelons. It was not certain if it was anthracnose, caused by Colletotrichum orbiculare, or gummy stem blight, caused by Didymella bryonae . However, for the sake of the discussion, the disease was called ‘anthracnose’ and ways of controlling it using cultural, varietal and chemical methods were outlined.

The importance of cultural control was emphasised, with due regard to seedling infections, crop rotation, drainage, site selection in relation to prevailing winds, weeds, the removal of trash after harvest.

Although there are watermelon varieties with resistance to strains of anthracnose, none have yet been developed that are resistant to gummy stem blight. However, this should not deter testing some of the varieties that are popular in other Pacific Island countries. Seeds will be obtained, probably from Fiji in the first instance.

It was suggested that chemical control should begin as soon as infected plants are seen, especially in times of wet weather. Even if no disease is seen, an application of fungicide three weeks after planting would seem appropriate. There was also a need to look at the spraying equipment of each farmer, the rate of the chemicals used as well as the method of application. This would be done at the next visit, possible in the second week of August.

Farmer trials

Farmers were keen to experiment, to consider cultural control measures, new varieties and improved pesticide application. It was decided to test four new varieties. Different groups would grow all the varieties in each of the four villages (Gwounasu, Hatodea, Nanadi and Takwa), with each group testing one variety. It was agreed that each farmer would grow a minimum of 20 plants along side the standard variety. Control measures against the fungus would be applied to the standard varieties and those under test, including the application of fungicide. Meetings would be held before planting to discuss the need for crop rotation (some farmers are growing watermelon on the same land each year), site selection, drainage, etc, and there would be training on pesticide application. A trial using BT is also a possibility, depending on the availability of the product in Honiara.

Monitoring by DAL/KGA/PestNet

The DAL/KGA and PestNet agreed the following monitoring plan after the workshop.

Action Who is responsible? When?
Send samples for identification:
Disease
Insects
J Saelea/GJ
M Ho’ota
Permit required if sent to NZ

Varieties:
∑ Discuss with Honiara suppliers
∑ Check those grown by PICs and elsewhere
∑ Order
∑ Permit to enter Solomon Is
Mariano Lauga
SH/ G.J
SH

Lily Wame
ASAP
ASAP


When disease ID made
Message from SH
Recruit Helen Tsatsia to the project Lily to talk to JS/JH ASAP
Meeting at Takwa Farmers + KGA/DAL/PestNet When the seed arrives. The meeting will share info on pest and disease control, and pesticide application
Guidelines for trial Steve/GJ – All to agree ASAP
Outline proposal for IPM of major arthropod pests Wilco Liebregt/M Ho’ota Early May

Closing remarks

Mariano Lauga thanked the participants for their input. It was important that the resource people obtained as much information as possible on the cultivation techniques as well as the pests and diseases of the area. Their patience was appreciated. We now have a sound platform from which to go forward. There is a much better understanding of the pests and diseases, their relative importance and potential methods of control.
Acknowledgement

The organisers of the workshop, KGA/PestNet and DAL, are grateful to Takwa community and surrounding villages for their hospitality and active participation during the two days of the workshop. We also would like to thank Lawrence Aldo, Chair of the BFN for hosting the workshops and taking care of the resource persons. The infoDev World Bank and the South Pacific Commission are thanked for financial support.

Grahame Jackson, PestNet
Sydney, 31 May 2004
Annex 1
Workshop participants
Farmers

Alick Sade
Betty Koudi
Brhuno Qga
Chris Martin
Daisy Fakaia
Daniel Aneke
Edison Ratu
Elson Ragafi
Erestus Ige
Ethel Samani
Everlyn Robert
Felix Laukasi
Felix Wao Usuli
Frank Tabai
Fred Daoga
George Kaeni
Gladys Dora Aeti
Jack Wao
Jackson Sipi
Jerriel Aeta
Koina Oiga
Lawrence Aldo
Lawrence Dime
Lucy Oligao
Macheal Bore
Mark Elson Kii
Matilda Sade
Meli Rofeta
Peter Robu
Philip Danita
Philip Lone
Ratu John
Redly Wiki
Reeves Tagini
Relmay Tabai
Rex Maenu



Robert Dede
Samo Taebo
Samson sade
Selister Kabi
Sisia Kabi
Valex Lega
Wao Kabolo
Watson Samo


Resource persons

DAL
Mariano Lauga
Lily Warme
Michael Ho’ota

KGA
Roselyn Kabu
Roselyn Lulumae

PestNet
Grahame Jackson
Wilco Liebregts

SPC
Stephen Hazelman



















Annex 2
Workshop timetable

Time Monday Tuesday
8.30 – 10.00

Official Opening (Community Leader)

Introductions and expectations (on small cards)

History of Watermelon cultivation in the Takwa area

About email and PestNet In the field: looking at the insects and diseases


10.00 - 10.20 Break Break
10.30 Small groups:
watermelon pest and disease stories
∑ what is the problem?
∑ What does it do?
∑ Where does it come from?
∑ What season?
∑ What causes it?
∑ What do you do about it? Watermelon calendar

What pesticides are used against what pest?

What do we know about the insects pests

What do we know about the diseases?
12.00 LUNCH LUNCH
1.30 Collect samples of pest and disease from watermelon gardens (same small groups) Discussion on the mot promising trials
2.30 Small Group Presentation
3.00 - 3.20 Break Break
3.30 Continue group presentations Concluding session


4.00 Ranking of problems – voting by group members


Annex 3

Pests collected from during surveys in North Malaita

Date Location Index No. No. vials Description
21 May 2004 Takwa. N. Malaita SI-M-T-101 2 Parasitoids ex. ‘green caterpillar’ on watermelon
20 May 2004 SI-M-T-102 1 Fly (parasitoid) ex. Aulacophora (adult) on watermelon [1 maggot emerged 21 May 2004]
21 May 2004 SI-M-T-103 2 ‘Red ant’ (Wasmannia auropunctata? On watermelon tending aphids (Aphis gossypii?)
22 May 2004 Malu’u, N. Malaita SI-M-Malu-101 2 Black aphid on long bean
22 May 2004 SI-M-Malu-102 1 Bug feeding on long bean
22 May 2004 SI-M-Malu-103 2 Ladybird beetle feeding on long and wing bean
21 May 2004 Takwa, N. Malaita SI-M-T-104 1 Bug feeding on watermelon