AVRDCThe World Vegetable Center

How to UseSex Pheromonefor ControllingEggplant Fruit

and Shoot Borer

F.C. Su, M.Y. Lin,and N.S. TalekarEntomology Unit

Sex pheromones are biological chemicals pro-duced by females of an insect species to attractmales of the same species for mating. The sexpheromone of an insect usually consists of amixture of two to four chemicals. The chemicalsand the proportion of the chemicals in a mixtureare very specific to insect species. Thus, a sexpheromone produced by a female of one insectspecies will attract males of that species only.Scientists have identified and even synthesizedthe sex pheromone chemicals of most moth andbeetle insects that feed on crop plants. Sex phero-mones of many of these pests are now commer-cialized and used by farmers in most countries.

One of the biggest advantages of using sexpheromones is that they are naturally occurringchemicals, produced all the time by insectsaround us, and are proven to be safe to humansand the environment. The chemicals evaporateand breakdown in the environment quickly. Thesynthetic chemicals are rather expensive, butsince they are needed in such tiny quantities,the use of these chemicals is economical.

Sex pheromone of eggplant fruit and shoot borer(EFSB), Leucinodes orbonalis (Guenée), hasbeen identified. It consists of two compounds,(E)-11-hexadecenyl acetate and (E)-11-hexadecen-1-ol. A 100:1 blend of the first andsecond chemical attracts maximum number ofEFSB male moths. This blend is now commer-cialized in India and Bangladesh.

In several field trials, pheromone-baited traps haveeffectively controlled EFSB and minimized theneed for toxic pesticides. The use of these trapswas found to be more cost effective than the useof pesticides. This brochure is designed to illus-trate how to use pheromone-baited traps for con-trolling EFSB in farmers’ fields.

Introduction

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Using sex pheromone

The use of sex pheromone for controlling insectpests require three items: a sex pheromone chemi-cal, a trap, and a support to hang the trap in thefield. Technically sex pheromones can be usedin three principal ways:

Monitoring: The presence of a pest insectemerging from within the same field or migratingfrom elsewhere into the newly planted field, canbe detected by installing a few pheromone-baitedtraps in the field. These traps will attract maraud-ing male moths. Once the occurrence of the pestis detected, a farmer can begin taking suitablecontrol measures.

Mass trapping: Sex pheromone can trap malemoths or beetles continuously, thus preventingmating and multiplication of the pest. For EFSB,this approach has proven to be particularly effi-cient and economical.

Mating disruption: Sex pheromone can be usedfor mating disruption, which is achieved by plac-ing high concentrations of pheromone, usuallywithout traps, at regular intervals throughout thefield. The high concentration of pheromone satu-rates the area resulting in males failing to findfemales, which produce very minute quantitiesof these chemicals, thus preventing mating andmultiplication of the pest.

Sex pheromone chemicals have to be purchasedin the market. These chemicals are dispensedon a suitable carrier such as a rubber or plasticsepta, inside a thin plastic tube or inside a plas-tic vial. Such formulation is usually called “sexpheromone lure” or simply “lure”. The lure isplaced in a suitable trap, which in turn, is hangedin the field.

Types of traps

Various types of traps are available commercially,while others can be made by farmers inexpen-sively at home. A pheromone-baited lure insidethe trap will bring male moths inside the trap.Proper trap design is critical to kill the pest onceit enters the trap. The type of trap to be used de-pends on the behavior of the male moth. Researchstudies show the traps most effective in control-ling EFSB adults are delta traps, winged traps,and funnel traps.

Delta traps

A delta trap consists of atriangular or delta-shapedcardboard tube. The lure ishung in the top angled por-tion and the bottom surfaceis coated with glue. MaleEFSB moths attracted tothe lure enter inside thedelta tube and while flyingaround the lure touch thelower sticky surface andbecome trapped in the gluefrom which they cannot es-cape.

In some cases, a 4-cm-wide slit is cut out alongthe lengths of the two sides. The slits provide ad-ditional openings for pheromone to seep out andmoths to fly inside the trap and get caught. Suchtrap is called an “open-delta” trap. Relatively moreEFSB moths are trapped in open delta comparedto delta traps. Delta/open delta traps are availablecommercially in most countries and can be as-sembled at home using locally available materi-als.

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Winged traps

A winged trap consists oftwo wing-shaped boardshooked together by a wire.The lure is hanged under-neath the top board. Thebottom is covered with asticky glue. The moth at-tracted to the lure flies in-side the trap around thelure until it accidentallytouches the lower surfacewhere it is trapped in theglue from which it cannotescape. Winged traps areavailable commercially insome countries and are difficult to construct us-ing homemade materials.

Funnel traps

A funnel trap consists of acover, a funnel with handle,an ‘O’ ring to fasten a plas-tic bag on the perimeter ofthe funnel, and a long plas-tic bag. The pheromonelure is attached to the un-derside of the cover and theopen end of a long plasticbag is wrapped aroundouter edges of the funnel.The two parts are attachedtogether by two or threepegs molded on the funnel.The male EFSB moth at-tracted to the lure flies around the lure, touchesthe smooth inner part of the funnel and slips downinside the plastic bag from which it cannot es-cape. Funnel traps are commercially available, es-pecially in South Asia, and cannot be constructedreadily using homemade materials.

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1. Start with a 56-cm-long and 28-cm-widesturdy paper or cardboard sheet.

Assembling Delta Traps

2. Cut the cardboard sheet and make five folds.

3. Cut slits of 15 mm × 3–4 mm each in the card-board at the six points shown, designated asA, B, C, D, E, and F. The width of the slits willdepend on the thickness of the cardboard—the thicker the cardboard, the wider the slits.

Assembling traps

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A C

DB

E

F

56 cm

28 cm

17 cm

Fold 2

Fold 4

Fold 5

Fold 1 Fold 3

17 cm 17 cm

5 cm

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4. Bend cardboard at Fold 1 and Fold 2 alongboth sides of the bottom. Bend flaps on ei-ther side of bottom inwards (Fold 4 + Fold 5)and insert the cutouts into slits A, B, C, D (leftphoto). Bend the cardboard at Fold 3 and in-sert the cutouts, which are already in slits Aand B into slits E and F (right).

5. Use a needle to make one hole in the center ofthe top. This is meant to hang the lure insidethe trap. then make two holes, 4 cm apart, inthe top center by piercing a sharp needlethrough both flaps as shown.

6. Hang the lure inside through the central holein the top (left) and insert two strings throughtwo holes as shown (right).

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7. Paste industrial strength glue uniformly on oneside of a 21 cm × 15 cm paper (left) and insertthe paper, with glued surface up, inside thetrap making sure it fits on the bottom tightly.

9. Fully assembled delta trap (left) and open deltatrap (right).

8. To prepare an open delta trap, at step 4, aftercutting six small slits in the board, cut out twoadditional 16-cm-long 4-cm-wide portions in thecenter of the two upright sides.

5 cm 5 cm

4 cm

16cm

A

B

C

D

E

F

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Assembling Winged Traps

1. A winged trap consists of (shown left to right):bottom and top, both sold as folded equal sizehard papers; two 4-mm-diameter 4-cm-longhollow straw tubes; and a 3-mm-diameter ironwire molded in the shape shown here.

2. Open the folded bottom forcefully which willexpose the inner sticky surface. Stretch thebottom completely to spread the glue overmost of the inner surface (left). Open the topwhich has plain inner surface (right).

3. Depending on type of lure, hook a wire throughthe loop of the plastic vial lure or pierce it throughthe narrow end of the rubber septum lure.

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4. With the help of a needle make a hole in thecenter of the top (left) and attach the lure tothe inner side of the top (right).

5. Iron wire is first pierced through the ready-madeholes in the center of both outer sides of thetop, as shown.

6. Both arms of iron wire are pierced completely,and the top is readied for assembling.

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8. Insert one hollow straw tube through the wireon either arm of the wire and push the tubesas close to the top as possible. Make surethe lure remains firmly attached.

9. Holding the top in one hand, push the openends of the wire through the ready-made holesin the center of the outer sides of the bottom,making sure the glued surface is facing thetop.

10.Both open ends of the wire pierced throughthe bottom are folded inwards to hold the bot-tom and top firmly together. The winged trap isready for use in the field.

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Assembling Funnel Traps

1. A funnel trap consists of a top, funnel withhandle, ‘O’ ring to fasten a plastic bag on theperimeter of the funnel, and long plastic bag.

2. The underside of the cover has round sockets.The central socket is used for attaching thelures (right). Outer sockets, two in this model,attach to the pegs of the funnel.

3. The lures, either rubber septa (left) or plasticvials (right), are attached in the central hole.The narrow end of a rubber septum fits tightlyin the socket, but a plastic vial should be fas-tened using a thin wire or strong thread.

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4. The plastic bag is then wrapped around outeredges of the funnel (left) and fastened tight byinserting an ‘O’ ring over the plastic bag until itreaches the upper edge of the funnel (right).

5. The top with either type of lure attached is thenfastened over the funnel by inserting the outersockets into the pegs on the periphery of thefunnel and the trap at this stage is ready foruse in the field.

6. This funnel trapis completelyassembled andready to go outto the field.

When to install traps

EFSB infestation starts when the eggplant cropbegins to flower. Pheromone-baited traps shouldbe erected at this stage and kept there throughthe rest of the season. The first EFSB moths enterfrom other eggplant fields or from dried plantsstored nearby. Starting about a month after flow-ering, most of the adults found in the field origi-nated within the same field. Traps must be main-tained until the last harvest to kill these insects.

How to install traps

The trap should be installed in a grid of 10 mthroughout the field starting 5 m from the border.This amounts to 10 traps per 0.1 hectare. Implanta sturdy stick firmly in the soil to support the trap.Then use a wire or sturdy thread to tie the trap tothe stick. The lure inside the trap should alwaysbe 10–15 cm above the crop canopy. This requiresmoving the trap higher as plants grow taller.

Replacing traps and lures

For delta and winged traps, their sticky surfacesget soiled due to dust and moth scales. If thesurface is not sticky enough, additional mothswill not be trapped. Check traps regularly andreplace their sticky bottoms when needed. In-tense sun, wind and rain can destroy entire traps.If this occurs, replace traps promptly. Funnel trapsare more durable in the field but their plastic bagscan be torn. Replace damaged bags to preventtrapped moths from escaping. Most commerciallures contains 2 mg of pheromone chemical. Suchlures usually remain effective for one month; there-fore, replace lures at least once a month.

Installation andcare of traps

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P.O. Box 42, Shanhua, Taiwan 741Tel: ++886-6-583-7801Fax: ++886-6-583-0009Web: www.avrdc.org

For more information on how to control EFSB, con-tact Dr. N.S. Talekar, Entomologist, AVRDC. E-mail: talekar@avrdc.org.

Related publications are listed below. Numerousother publications are available at the AVRDCweb site. Go to <www.avrdc.org>.

How to Control Eggplant Fruit and Shoot BorerDevelopment of an Integrated Pest ManagementStrategy for Eggplant Fruit and Shoot Borer inSouth AsiaA Farmer’s Guide to Harmful and HelpfulInsects in Eggplant FieldsHow to Use Sex Pheromone of Eggplant Fruitand Shoot BorerSocio-economic Parameters of Eggplant PestControl in Jessore District of Bangladesh

Department forInternational DevelopmentDFID

The production of this publication was funded bythe UK Department for International Development(DFID). However, the views expressed are notnecessarily those of DFID.

2004

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More information

Acknowledgements

AVRDCThe World Vegetable Center