Original articl e Efficacy of coloured sticky traps for citrus thrips Scirtothrips aurantii Faure (Thysanoptera, Thripidae ) in mango ecosystems of South Afric a Tertia Gravéa * Efficacy of coloured sticky traps for citrus thrips Scirtothrips aurantii Faure Johannes Human Giliomee b (Thysanoptera,Thripidae) in mango ecosystems of South Africa . Kenneth Llewellyn Pringle b Abstract — Introduction . The South African citrus thrips, Scirtothrips aurantii Faure a ARC-ITSC , (Thysanoptera : Thripidae), is a pest of mango (Mangifera indica L.), in southern Africa . Private Bag X11208 , Scirtothrips aurantii cause lesions to young fruit and damage to young mango growth results Nelspruit 1200 , in leaf malformation and stunted growth . Materials and methods . The sticky traps of vari- South Africa ous colours were tested in mango orchards in South Africa for their attraction of adult S . auran- tii . Results. Yellow colour was superior to green, red, white and blue ones to catch S b University of Stellenbosch . auran- , Green, red, white and blue traps attracted similar numbers of thrips Private Bag X1 , although S. aurantii Matieland 7602 , tended to respond more to green than red, white and blue in this sequence . Conclusion . South Africa Yellow traps can be used effectively for assessing activity levels of S. aurantii in mang o orchards . © Éditions scientifiques et médicales Elsevier SA S South Africa / Mangifera indica / Scirtothrips aurantii / traps / attractants Efficacité des pièges collants colorés pour la capture du thrips des agrumes , Scirtothrips aurantii Faure (Thysanoptera, Thripidae) , dans des écosystèmes de manguiers en Afrique du Sud . Résumé — Introduction . Le thrips sud-africain des agrumes, Scirtothrips aurantii Faure (Thysanoptera, Thripidae), est un parasite du manguier (Mangifera indica L .) en Afrique méri- Correspondence and reprints dionale . Il cause des lésions au jeune fruit et endommage la croissance de jeunes arbres e n provoquant une malformation des feuilles et un retard de croissance . Matériel et méthodes . Des pièges collants de différentes couleurs ont été testés en vergers de manguiers en Afriqu e Received 25 October 1999 du Sud vis-à-vis de leur pouvoir attractif dadultes de S . aurantii. Résultats. La couleur jaune Accepted 9 March 200 0 sest révélée meilleure que le vert, rouge, blanc ou bleu pour capturer les individus de S . auran- tii. Les pièges verts, rouges, blancs ou bleus ont attiré des nombres semblables de thrips bie n que S . aurantii ait tendu à répondre davantage au vert quau rouge, au blanc et ou bleu, res- Fruits, 2000, vol . 55, p . 253–25 8 pectivement. Conclusion . Des pièges jaunes peuvent être employés efficacement pour évalue r © 2000 Editions scientifique s des niveaux dactivité du thrips S. aurantii en vergers de manguiers t et médicales Elsevier SA S . © Éditions scientifiques e All rights reserved médicales Elsevier SA S RESUMEN ESPAOL, p. 257 Afrique du Sud / Mangifera indica / Scirtothrips aurantii / piège / attractif Fruits, vol . 55 (4) 253 T. Grové et al. 1 . introductio n 2. materials and method s The South African citrus thrips, Scir- To determine the colour preferences of tothrips aurantii Faure (Thysanoptera : S. aurantii, five different colours were used : Thripidae), is an important and well docu- blue, yellow, green, red and white . Blu e mented pest of citrus in southern Afric a was included because certain thrips specie s [1-4] . S. aurantii also causes lesions to are attracted to blue, for example the west - young fruit of the mango (Alangifera indica ern flower thrips Frankliniclta occidentalis L .) and its status as a pest of this crop ha s (Pergande) [I1, 13] . Blue sticky traps ar e increased over the past number of years [5] . used for monitoring thrips• in nectarin e Fruits with large lesions are not suitable fo r orchards in South Africa [19] . Yellow traps were included because yellow is the pre- the export market although the damage i s ferred trap colour for monitoring S. auran- merely cosmetic . The damage to youn g tii in citrus orchards in South Africa [18] . mango growth results in leaf malformatio n Red and green were used because the y and stunted growth . resemble the young mango leaves whil e Before integrated pest managemen t white traps were included because white i s can successfully be implemented agains t highly attractive to some thrips species [10] . S. aurantii in mango orchards, an effectiv e The yellow traps consisted of non-fluo- technique for monitoring population num- rescent yellow polyvinyl chloride (140 mm bers must be available in order to deter - x 76 mm x 0 .2 mm) obtained from Capes - mine whether the application of contro l pan . The white, blue, red and green trap s measures is required, to determine the cor - were cut from coloured cardboard . Th e rect timing of control applications and fo r spectral reflectance characteristics of th e gauging their effect . Monitoring thrips using colours were determined at 10 nm interval s coloured sticky traps is well documented from 380 to 790 nm, using a Perkin Elma r [6-131, but it has not yet been used in mango Lambda spectrophotometer ; BaSO 4 (com- orchards. pressed powder supplied by Merck) stan- dard = 100 % (figure 1) . Traps were coate d When white, yellow, blue, red, gree n on both sides with a sticky adhesive , and black sticky traps were used to capture Fly-tac . S. citei (Moulton) on navel oranges in Cali- fornia, the white traps caught greater num - Field work was carried out in mang o bers [8] . Moreno [14] suggested the use of orchards at the Insitute for Tropical an d yellow to monitor S. citei. The fluorescent Subtropical Crops Nelspruit Experimenta l Saturn yellow trap was developed for mon- Farm (25° 26 S, 30° 58 E) in the Mpuma - itoring S . aurantii in citrus orchards i n South Africa [15, 16] . These traps are no t loo commonly used because they are expen- 8 0 sive and cumbersome [17] . Grout an d 2.- Richards [181 found that smaller non- =86 0 fluorescent yellow card traps on the sunny m 40 side of trees were more attractive t o t cc 20 S. aurantii than Saturn yellow traps used on the shady side . Yellow card traps wer e o 400 450 500 550 600 650 700 750 m m also less expensive and easier to use . Cit- — Yellow - -Green White — Blue -- Re d rus producers were therefore encourage d to use them . As sticky traps could also b e useful for monitoring population fluctua- Figure 1 . Percentage of reflectance of light from surface s tions of S. aurantii in mango orchards, th e of colour traps as measured with a Perkin Elme r attraction of traps of different colours fo r Lambda 9 spectrophotometer ; S. aurantii was evaluated in this study . BaSO4 standard = 100 % . 254 Fruits, vol . 55 (4) S . aurantii in mango ecosystems of South Africa Tanga Province of South Africa . One set of the five different colours was placed at fou r 50 different localities on the farm . A set con- 45 sisted of one trap of each colour . The first 40 set of traps was placed in a Sensation mango 35 tree orchard, the second in a mango orchar d 30 consisting of different selections, the thir d 25 in a Tommy Atkins orchard and the last se t 20 in mango trees grown from seed . All trees 15 ~ used were older than 10 years . In the first 10 two orchards, fungicides were sprayed 5 s against powdery mildew, anthracnose , and 0 A/\ !v_~ ~ y •Ì~`.c~ bacterial black spot. Bait sprays were use d against fruit flies (Tephritidae) 4/4 16/5 27/6 1/8 5/9 10/10 14/11 19/12 23/1 27/2 . At the last 1995 1996 two locations, no pesticides were applied . — Yellow •--- Green White — Blue --- Red Traps were hung on the outside of five randomly chosen trees and rotated every 3. results Figure 2 . week . They were placed on the sunny north- Weekly catches ern side of the trees, 1 .5 m from the ground . of Scirtothrips aurantii Scirtothrips aurantii adults were presen t on coloured sticky trap s Traps were changed weekly except on two in mango orchards throughout the year (fig- in mango orchards from Apri l occasions in April and May 1995 when traps ure 2) . During August, numbers started to 1995 to March 199 6 were changed fortnightly . After removal , increase and reached a peak from the en d (South Africa). each trap was wrapped in clear polyethyl- of August to September. High numbers als o ene plastic and brought to the laboratory . occurred at the beginning of November an d The number of S. aurantii present on both during January . This corresponded wit h sides of the traps was counted using a stere o flushing periods . During February to July microscope . The trapping period was fro m their numbers remained low. April 1995 until March 1996 . Adults of S. aurantii responded signifi- The cumulative number per locality was cantly more to yellow than any other colou r analysed using an analysis of variance . (table I) . No significant difference was pres - Tukeys multiple range test was used to ent between the numbers attracted b y separate differences . green, red, white and blue . There was a Table I . Mean cumulative numbers of Scirtothrips aurantii caught on traps of different colours . Averages not followed by the same letter differ at the level of p = 0 .05 . Tukeys multiple range test was used to separate differences . Trap colour Mean cumulative number Standard error of mea n Yellow 333.500 a 36 .762 Green 130 .250 b 34.577 Red 115 .000 b 36 .28 4 White 68 .500 b 20 .698 Blue 39.500 b 4 .500 Mean-squared error 2 491 .43 Error degree of freedom 1 2 Least significant difference 112 .507 Coefficient of variance 36 .341 Fruits, vol .