Integrated Control in Citrus Fruit Crops IOBC/wprs Bulletin Vol. 6, 21 pp.213-217 Mass Trapping for the Control of the Mediterranean Fruit Fly Ceratitis capitata in Citrus Orchards in Tunisia Mediouni-Ben Jemâa Jouda, Bachrouch Olfa, Skillman Stephan, Kerber Elmar Institut National de la Recherche Agronomique de Tunisie, Laboratoire de Protection des Végétaux, Rue Hedi Karray, 249 Tunis, Tunisia; Unité de recherche de physico-chimie moléculaire (URPCM). IPEST BP : 51 27 La Marsa, Tunisia; Syngenta Agro Serves AG, PO Box 233, CH-8157, Düsseldorf, Switzerland Abstract: This work aims to evaluate the mass trapping technique based on the use of female foodattractant lure Tri-pack and the insect growth regulators lufenuron for the control of medfly in citrus field. These methods were used as alternative to chemical control with spraying in Washington navel orange orchards in 26 and 27. The assessment of the mass trapping technique efficacy was based on adult Medfly population reduction expressed by weekly recording of male captures together with the assessment of fruit damage at harvest. Trials were conducted using a density of 2 trap/ha. Results indicated significant differences in male captures and fruit damage percentages between the two tested methods and the control ( spraying). Concerning adult males Medfly captures, reductions of 62.86% and 47.29% were achieved respectively for the mass trapping based on lufenuron and Tri-pack respectively in 27. For fruit damage assessment, results showed reduction of 9.68% for the mass trapping based on lufenuron and 31.99% for the mass trapping based on Tripack compared to the control. Key words: Medfly, IPM, insecticide, Tri-pack, lufenuron Introduction The Mediterranean fruit fly (Medfly), Ceratitis capitata, is one of the most devastating pests of fruits and vegetables worldwide (Chueca, et al., 27). In Tunisia, Medfly is one of the key pests on citrus crops. Current control program is mainly based on applications of organophosphate insecticides, especially mixed with protein baits. Among the interesting alternatives, the mass trapping technique has proven to be a powerful weapon in the control of C. capitata, and its application in Mediterranean countries has currently increased notably as a control method (Navarro-Llopis et al., 28). is based on the use of insect growth regulators as chemosterilants agents (ex. Lufenuron) and the use of female food-attractant lure (Tri-pack ). Lufenuron is the most used and field tested chitin synthesis inhibitor against Ceratitis capitata. This compound showed good potential in the control of the Medfly populations. Lufenuron can interrupt Medfly reproduction and prevent the hatching of eggs (Licudine et al., 21). On the other hand, field trials using Tephri-traps baited with the three food lures Tri-pack (ammonium acetate, putrescine and trimethylamine) at the density of 2 trap ha-1 outperformed the bait spraying in reduction of insect population and decrease of fruit damage (Mediouni et al., 21). This work aims to evaluate the mass trapping technique based on the use of female foodattractant lure Tri-pack and the insect growth regulators lufenuron for the control of medfly in citrus field. 213
214 Materials and Methods Experimental fields Trials were conducted in two experimental fields planted with Washington navel orange variety (Citrus sinensis). The first field had 6 ha area with a tree-spacing of 6 m x 6 m leading to a density of 3 trees/ha. This field was used for the mass trapping experiment based on lufenuron. The second experimental field used for mass trapping trial with Tri-pack had 5 ha area with tree spacing of 5 m x 5 m leading to a density of 4 trees/ha. These two fields were equally divided between mass trapping and conventional chemical treatments (three elementary plots for each treatment). The trials were conducted during 26 and 27. Traps, lures and insect monitoring The mass trapping experiments were performed using Tephri-traps baited with synthetic female-targeted food attractant lure marketed as Tripack (5 mg a.i. ammonium acetate, 5 mg a.i. putrescine, and 2.5 mg a.i. trimethylamine; Kenogard SA, Barcelona, Spain) together with a tablet of dichlorvos (.5 mg a.i. dimethyl 2,2-dichloroethenyl phosphate DDVP) (Biagro, SLL, Valencia, Spain) as insecticide. Yellow plastic bait stations (Syngenta Crop Protection AG) containing a bait-gel based on lufenuron (A-14619 A RB 3, bait with 3% lufenuron) were used for the mass trapping lufenuron trial. In both experiments, a density of 2 traps/ha was tested. Males C. capitata were monitored by McPhail traps baited with the parapheromone Trimedlure. Traps were hung in the trees at a height of 1.5 m and were checked and the caught insects were counted weekly. Insecticide For the chemical treatment, (dimethoxy-thiophosphorylthio-2, succinate d éthyle C1H19O6PS2) was used at the dose of 5 cc/ha each 1 days. Fruit damage assessment In order to determine the percentage of fruit damage due to the Medfly, ten trees were randomly selected per mass trapping and treated orchards. On each tree every fruit was weekly checked for Medfly punctures and the infested ones were marketed to be recognized in the subsequent examination. Statistical analyses The reduction of Medfly population was calculated by the method of Abbott expressed by the formula C T, where C = rate of Medfly captures in the control field, T = rate of Medfly TR = x 1 C captures in the treated field and TR = rate of population reduction. Results were expressed as percentage of fruit damage. Data was compared using the Student T-Test at a risk level of 5% (Dagnelie, 1986). Results and discussion Lufenuron and Tri-pack effects on Medfly population Results showed reductions of 66.52% and 62.86% in adult males Medfly captures respectively for the years 26 and 27 concerning the mass trapping trials based on lufenuron (Figure 1). For mass trapping trials based on the food-attractant Tri-pack, results showed reductions in adult males Medfly captures of 36.48 and 47.29% respectively for 26 and 27 (Figure 2).
215 5 4 3 male/trap/week 3 male/trap/week 25 26 27 2 15 2 1 1 5 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 Figure 1: Weekly captures of males C. capitata in lufenuron mass trapping and treatments in 26 and 27. 5 4 Male/trap/week mass trapping 1 male/trap/week 8 26 27 mass trapping 3 6 2 4 1 2 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 Figure 2: Weekly captures of males C. capitata in Tri-pack mass trapping and treatments in 26 and 27 Effects of Lufenuron and Tri-pack on fruit damage at harvest For fruit damage assessment, results showed no statistical differences between mass trapping technique based on lufenuron and treatment in 26. Furthermore, during the year 27, we observed 9.68% of fruit damage in the treated area against 13.14% in the plot (Figure 3a). Results demonstrated that the percentage of punctured fruit at harvest is significantly different between mass trapping based on Tri-pack and treatments in both fields. Mean percentages of punctured fruit were lower in the mass trapping plot than in (31.39% and 28.11%; 37.% and 27.1) for 26 and 27 respectively (Figure 3b). This work reported important reduction of the insect population and a visible decrease of the percentage of fruit damage in plots treated with mass trapping (either with Lufenuron or Tri-pack ) comparable to standard farmer treatments. In this context, Cunningham et al. (1978), Agunloye (1987) and Mc-Quate et al (25) reported that the mass trapping technique was efficient on the reduction of Mediterranean fruit fly populations in citrus orchards.
216 5 puncture (%) mass trapping 5 puncture (%) Malathion 4 4 3 a 3 b 2 2 1 1 26 27 Figure 3: Effects of lufenuron and Tri-pack mass trapping techniques on damage fruit percentage at harvest (a: lufenuron, b: Tri-pack ) 26 27 Similar works demonstrated that the lufenuron used as chemosterilizing agent at a dose of 1,-ppm against C. capitata leaded to an important sterilizing activity as hatching inhibitors (Castillo et al., 2). In Morocco, El Moubariki (25) indicated that the system Match Medfly RB3 in small plot trials showed an efficacy comparable to the conventional chemical control. In Tunisia, promising results were obtained using mass trapping based on lufenuron and suggested that this technique could be employed as an alternative control method in Tunisian citrus orchards (Bachrouch et al., 28). Moreover, Mediouni et al., (21) reported the important role of the mass trapping technique using Tri-pack on the reduction of Mediterranean fruit fly populations in citrus orchards in Tunisia. Field trials using Tri-pack at the density of 2 trap ha-1 outperformed the bait spraying in reduction of insect population and decrease of fruit damage. In this context, field trials conducted in several countries showed that traps baited with the 3 component attractants captured equal or greater numbers of females than the McPhail-type traps baited with an aqueous solution of protein hydrolysate NuLure and borax as preservative (Epsky et al., 1999, Katsoyannos et al., 1999a, b). This research report the importance of the mass trapping technique for the control of Medfly in citrus orchards in Tunisia compared to the chemical treatment with. Nevertheless, the economic costs of such technique must be evaluated and optimized to be used on larger scale. References Abbott, W.S. 1925. A method for computing the effectiveness of an insecticide. J. Econ. Entomol. 18: 265-267. Agunloye, O.J. 1987. Trapping and chemical control of Ceratitis capitata (Wied) (Diptera,Tephritidae) on sweet orange (Citrus sinensis) in Nigeria. J. Hortic. Sci. 62: 269-271. Bachrouch, O, Mediouni-Ben Jemâa, J., Alimi, E., Skillman, S, Kabadou, T. & Kerber, E. 2. Efficacy of the lufenuron bait station technique to control Mediterranean fruit fly Ceratitis capitata Wied in Citrus orchards in Northern Tunisia. TJPP. 3: 35-45. Castillo, M., Moya, P., Hernandez, E., & Primo-Yufera, E. 2. Susceptibity of Ceratitis capitata Wiedemann (Diptera: Tephritidae) to entomophatogenic fungi and their extracts. Biol. Cont. 19: 274-282.
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