Acta agriculturae Slovenica, 120/4, 1–6, Ljubljana 2024 doi:10.14720/aas.2024.120.4.18925 Original research article / izvirni znanstveni članek Codling moth management by low doses of sugars on ‘Royal Gala’ apple trees Abd-el-Kader TIFFRENT 1,2 , Nadia LOMBARKIA 1 Received June 10, 2024; accepted September 08, 2024 Delo je prispelo 10 junij 2024, sprejeto 08. september 2024 1 Laboratory of Improvement of the Phytosanitary Protection Techniques in Mountanious Agrosystems, Agronomy Department, ISVSA, University Batna 1, Algeria 2 corresponding author Codling moth management by low doses of sugars on 'Royal Gala' apple trees Abstract: Codling moth (CM) is a key pest in apple or- chards in Algeria. Its control is difficult because of its ability to develop resistance to pesticides. Besides, concern about the safety of these pesticides for human health and the environment has led to regulatory actions that have reduced the availability of these products to growers. Thus, the use of eco-friendly al- ternative methods is encouraged. In this context, foliar spraying using fructose (100 ppm) and glucose (100 ppm) against CM larval stages on 'Royal Gala' apple, compared to the control and insecticide (Deltamethrin), was assessed in an orchard located in Beni Fedhala province (Batna-Algeria). The obtained results confirmed that the spraying of glucose and fructose increased the percentage of healthy fruits at harvest, the percentages of healthy fallen fruits and the total healthy fruits. Further, the number of diapausing larvae in corrugated cardboard banding was reduced. In addition, our study shows that the number of chrysalis was significantly lower and different from the number of male and female larvae, which are identical. Key words: Codling moth, glucose, fructose, Deltame- thrin, 'Royal Gala'. Uravnavanje jabolčnega zavijača z majnimi odmerki slad- korjev na jablanah 'Royal Gala' Izvleček: Jabolčni zavijač (CM) je ključni škodljivec v sadovnjakih jablan v Alžiriji. Njegovo uravnavanje je težavno zaradi njegove sposobnosti razvoja rezistence na pesticide. Po- leg tega je skrb zaradi škodljivosti pesticidov ljudem in okolju privedla k načinom uravnavanja, ki zmanjšujejo dostopnost pesticidov sadjarjem. Vzpodbujane so okolju prijazne metode uravnavanja škodljivca. V tem kontekstu je bilo opravljeno foliarno škroplenje s fruktozo (100 ppm) in glukozo (100 ppm) za zatiranje jabolčnega zavijača v larvalnem štadiju v nasadu jablan 'Royal Gala', v primerjavi s kontrolo in upor- abo insekticida (Deltamethrin), v sadovnajaku province Beni Fedhala (Batna-Algeria). Dobljeni rezultati so potrdili, da je škropljenje z glukozo in fruktozo povečalo odstotek zdravih plodov ob obiranju, kot tudi odstotek odpadlih zdravih plodov in celokupni delež zdravih plodov. Zmanjšalo se je tudi število mirujočih gosenic v pasteh iz valovite lepenke. Dodatno je ra- ziskava pokazala, da se je število bub zmanjšalo in da je bilo različno od sicer identičnih moških in ženskih gosenic. Ključne besede: jabolčni zavijač, glukoza, fruktoza, Del- tamethrin, 'Royal Gala'. Acta agriculturae Slovenica, 120/4 – 20242 A. K. TIFFRENT et al. 1 INTRODUCTION Cydia pomonella (Linnaeus, 1758) causes large economic losses for the fruit yield in Algeria. Codling moth resistance to many insecticides has been observed in several areas (Bouvier et al., 2001; Sauphanor et al., 2006; Charmillot and al., 2007; Whalon et al., 2008; Rodríguez et al., 2011 et 2012; Pajac et al., 2019). Currently, it is essential to design eco-friendly control systems. The concept of exogenous application of sugars on apple trees to reduce the damage of C. pomonella in commercial orchards has shown increased interest in several countries (France, Italy, Greece, and Algeria) with an efficacy percentage of 40–59  % (Derridj et al., 2011). The studies of Lombarkia (2002) and Lombarkia et al. (2008) and (2013) testing the link between six metabolites (glucose, fructose, sucrose, sorbitol, quebrachitol, and myo-inositol) and C. pomonella egg-laying behavior to re- duce the damage, in addition, Tiffrent and Lombarkia (2022a) showed that the glucose and fructose treatments significantly reduced the number of eggs led to similar results as for the ref- erence chemical treatment during the first and third generation flights on ‘Golden Delicious’ and during the fourth flight on ‘Royal Gala’. Furthermore, according to Tarkowski et al. (2019), the concept of “sweet immunity” postulates that sugar metabo- lism and signaling influence plant immune networks. The objective of this study was to determine the effect of the fo- liar application of sugars specifically, fructose alone and glucose alone, and insecticide compared with a control in apple fruit orchard and to design alternative eco-friendly control systems to substitute conventional chemical programs. 2 MATERIALS AND METHODS 2.1 STUDY SITE AND TREATMENTS ‘Royal Gala’, is a highly esteemed variety famed for its sweet, crisp apples. According to the Food and Agriculture Organiza- tion of the United Nations (FAO), the major apple cultivars can be roughly divided into either red-colored bearing fruit, such as ‘Red Delicious’, ‘Fuji’, and ‘Royal Gala’, among others, and yellow/green-colored bearing fruits, such as ‘Golden Delicious’, ‘Granny Smith’, and ‘Orin’ (Korbon, 2021). ‘Golden Delicious’ and ‘Royal Gala’ are the preferred apple varieties for juice pro- duction due to their good balance between sweetness, bitter- ness, and aroma compounds (Ramadan and Farag, 2022). The experiment was carried out in 2021 in a ‘Royal Gala’ ap- ple orchard (35°21'21,6" N, 006°01' 16,5" E) located in Batna province (eastern Algeria). The treatments were adjusted in a randomized Latin square with four repetitions against C. po- monella. All four modalities are then distributed within each of the four plots, and each plot has three trees. The studied orchard was managed under common practices of the region. It had a surface area of 2.5 ha (three apple varieties, apricot, peach, plum, and nectarine trees) with 450 ‘Royal Gala’ apple trees. The trees were 11 years old, and the plant spacing was 4 m × 4 m. The treatments were applied using an electrical pressure sprayer (12 V-12 Ah) with a capacity of 16 l. The tested modalities were fructose, glucose, and insecticide Decis (its active ingredient is Deltamethrin), in addition to the unsprayed control. The tested treatments, their doses, and periods of application are reported in Table 1. 2.2 DAMAGE ASSESSMENTS The following variables were measured; the percent- age of healthy fruit at harvest, the percentages of healthy fallen fruits and the percentage of total healthy fruits. All variables where based on the total number of fruits pro- duced per tree. 2.3 COUNTING DIAPAUSING LARVAE To collect diapausing larvae of the CM, all trees of the four plots were selected, a strip of corrugated card- board (20 cm wide) was placed around the trunk of each tree and at a height of 20 cm from the ground, installed between the mid-April and the end of September, and the captured diapausing larvae were counted, making it pos- sible to distinguish between male larvae, female larvae, and chrysalis. According to Kuyulu and Genc (2019), the fifth instar larvae were used to determine the sex of the Treatments Doses Periods of application Control (Untreated) Fructose (Fluka Biochemika) Glucose(Fluka Biochemika) Decis 25 EC 25 g l-1 Deltamethrin (Bayer) Control (Untreated) 10 g 100 l-1 (100 ppm) 10 g 100 l-1 (100 ppm) (0,5 l) 1000 l-1 The morning treatments (sugars and insecticide) were carried out every 20 days throughout the season from the flowering end until harvest (Derridj et al., 2012). Table 1: Tested treatments, their doses, and periods of application Acta agriculturae Slovenica, 120/4 – 2024 3 Codling moth management by low doses of sugars on 'Royal Gala' apple trees larvae. Male larvae had two unique dark spots near the end of the dorsal side. So the distinction is based on the presence or absence of these dark spots (the male genital system), clearly visible on the dorsal side. 2.4 STATISTICAL ANALYSIS The statistical procedure for the obtained data was performed with SPSS software. The means between each variable, percentage of healthy fruit at harvest, percent- age of healthy fallen fruits and the percentage of total healthy fruits, number and type of diapausing larvae were compared by ANOVA on a rank test, followed by post hoc analysis using Fisher’s and Tukey’s tests or the Kruskal-Wallis test. A P-value of 0.05 was used to estab- lish statistical differences in all tests. 3 RESULTS AND DISCUSSION 3.1 PERCENTAGE OF HEALTHY FRUITS AT HAR- VEST Foliar sprays of glucose have induced a signifi- cant increase in the percentages of healthy fruit at har- vest compared to the untreated control. On the other hand, fructose generated a percentage of healthy fruits at harvest similar to that of the insecticide. The analy- sis of variance (Kruskal-Wallis test) (p < 0.05) identifies three groups: control (51.18 ± 2.57 %), glucose (78.18 ± 0,80 %), followed by the spraying of fructose and insec- ticide (82.91 ± 0.52 % and 83.76 ± 0.99 %, respectively) (Figure 1). 3.2 PERCENTAGE OF HEALTHY FALLEN FRUITS The spraying of glucose and fructose induced a significant increase in the percentages of healthy fallen fruits compared to the untreated control, and their per- centages are similar to those of the insecticide. The analy- sis of variance (ANOVA) followed by the Tukey test (p < 0.05) identified two groups: control (41.41 ± 0.79 %), followed by the spraying of glucose, fructose, and insec- ticide (64.89 ± 2.24 %), 64.87 ± 2.04 % and 62.21 ± 2,55 % respectively (Figure 2). 3.3 PERCENTAGE OF TOTAL HEALTHY FRUITS Foliar sprays of glucose have increase significantly the percentage of total healthy fruits and fructose gener- ated a percentage of total healthy fruits similar to that of the insecticide. The analysis of variance (ANOVA) fol- lowed by the Tukey test (p < 0.05) classified the tested treatments in three group: control (47.08 ± 1.48), glu- cose (75.27 ± 0.85 %), fructose and insecticide (78.73 ± 0.64 %, 80.93 ± 1.01 % respectively (Figure 3). 3.4 COUNTING THE NUMBER OF DIAPAUSING LARVAE The spraying of glucose and fructose led to a result similar to that of the insecticide. It caused a significant decrease in the number of diapausing larvae compared to the untreated control. The analysis of variance (Krus- kal-Wallis test)(p < 0.05) identified two groups: control (56.92 ± 2.73  %), followed by the spraying of glucose, Figure1: Percentage of healthy fruits at harvest in the apple orchard (n = 12) under different modalities (control, fructose, glucose, insecticide). Different letters indicate a significantly different percentage of healthy fruits at harvest (p < 0.05). Figure 2: Percentage healthy fallen fruits in the apple orchard (n = 12) under different modalities (control, fructose, glucose, insecticide). Different letters indicate a significantly different percentage of healthy fallen fruits (p < 0.05). Acta agriculturae Slovenica, 120/4 – 20244 A. K. TIFFRENT et al. fructose, and insecticide (6.17 ± 1.58 %), 10.08 ± 2.58 %, and 4.75 ± 0.82 %, respectively (Figure 4). 3.5 COUNTING THE NUMBER OF MALE AND FEMALE LARVAE AND CHRYSALIS The number of male and female larvae was not sig- nificantly different. Furthermore, the number of chrysa- lis was significantly lower and different in comparison to the number of male and female larvae. The analysis of variance (Kruskal-Wallis test) (p <0.05) revealed two groups: the number of male and female larvae (7.06 ± 1.15 % and 11.5 ± 2.02 %, respectively), followed by the number of chrysalis, 0.92 ± 0.27 % (Figure 5). It is apparent from our findings, that the spray of exogenous foliar application at doses of 100 ppm for glu- cose and fructose has increased the percentage of healthy fruits and reduced damage compared to the control. These results are partly similar to the results of some pre- vious experiments conducted on ‘Starkrimson’, ‘Golden Delicious’, and ‘Royal Gala’ varieties (Abdesslem, 2016; Arnault et al., 2015 and 2016; Meradi, 2015; Nasri, 2015; Tiffrent and Lombarkia, 2021). As discussed in details in the article of Tiffrent and Lombarkia, (2022b) and their finding that the ‘Royal Gala’ variety was better suited than the other varieties to the concept of exogenous foliar application at doses of 100 ppm for glucose and fructose, because they have increased the percentage of healthy fruits and reduced the percentage of damaged fruits at harvest (percentage of damaged fruits: 15.27  % and 16.45 %, respectively, compared to the control 76.99 %). The same authors mentioned that the percentage of fallen and damaged fruits at harvest was 31.93 % and 19.16 %, respectively, compared to the control (32.54  %); while, the percentage of healthy fallen fruits was 68,07 % and 80,84 % respectively, compared to the control 67,46 %, also, the spraying of glucose and fructose induced a sig- nificant decrease in the number of diapausing larvae compared to the untreated control (glucose 10.08  %, fructose 06.67 %, and control 34.50  %, respectively). Thus, the present study has confirmed the promising re- sults recorded for this variety (Royal Gala). Meradi (2015) has demonstrated in her study on the ‘Starkrimson’ variety that that the number of males was more important than that of the female larvae, and that of the chrysalis was lower. Walters et al. (2013) explained that induced resistance is a host response; its expression under field conditions is likely to be influenced by a num- ber of factors, including the environment, genotype, crop Figure 3: Percentage of total healthy fruits in the apple orchard (n = 12) under different modalities (fructose, glucose, insecti- cide). . Figure 4: Number of diapausing larvae (n = 12) under different modalities (control, fructose, glucose, insecticide). Different letters indicate a significantly different number of diapausing larvae (p < 0.05). Figure 5: Number of male and female larvae and chrysalis (n = 12) under different modalities (control, fructose, glucose, insecticide). Different letters indicate a significantly different number of diapausing larvae (p < 0.05). Acta agriculturae Slovenica, 120/4 – 2024 5 Codling moth management by low doses of sugars on 'Royal Gala' apple trees nutrition, and the extent to which plants are already in- duced. 4 CONCLUSION In conclusion, our study has shown that codling moth can be effectively managed by using exogenous ap- plications of sugars to reduce damages. However, sugars can induce resistance to C. pomonella. These results open up new methods of integrated pest management. In the future, it may be desirable to investigate the effects of foli- ar application of single sugars on the ‘Royal Gala’ variety. 5 REFERENCES Abdesslem, Z. (2016). Utilisation des sucres et virus de la gran- ulose pour la lutte contre le carpocapse Cydia pomonella L. (Lepidoptera, Tortricidae) en verger de pommier situé dans la région d'Inoughissen (Wilaya de Batna), Magister dis- sertation, Institut d'Agronomie, Université de Batna, 79 p. Arnault, I., Bardin, M., Ondet, S., Furet, A., Chovelon, M., Kasprick, A. C., Marchand, P., Clerc, H., Davy, M., Roy, G., Romet, L., Auger, J., Mançois, A., and Derridj, S. (2015). Utilisation de micro-doses de sucres en protection des plantes. Innovations Agronomiques, 46, 1-10. Arnault, I., Ondet, S. J., Lombarkia, N., Warlop, F., and Derridj, S. (2016). Preliminary results of foliar applications of fruc- tose to reduce codling moth Cydia pomonella L. (Lepidop- tera, Tortricidae) damages on apple tree in organic farm- ing. In Ecofruit. 17th International Conference on Organic Fruit-Growing: Proceedings, 15-17 February, Hohenheim, Germany, pp. 196-199. Bouvier, J.C., Buès, R., Boivin, T., Boudinhon, L., Beslay, D., and Sauphanor, B. (2001). Deltamethrin resistance in the cod- ling moth (Lepidoptera: Tortricidae): inheritance andnum- ber of genes involved. Heredity, 87(4), 456-462. https://doi. org/10.1046/j.1365-2540.2001.00928.x Charmillot, P.J., Pasquier, D., Salamin, C., Briand, F., Ter-Ho- vannesyan, A., Azizian, A., and Velcheva, N. (2007). Dé- tection de la résistance du carpocapse Cydia pomonella: Tests d'insecticides sur des chenilles diapausantes de Suisse, d'Arménie et de Bulgarie. Revue Suisse de Viticulture, Ar- boriculture, Horticulture, 39(6), 385-389. Derridj, S., Arnault, I., Nicholas, A., Birch, E., Elad, Y., Lom- barkia, N., Couzi, P., and Pierre, P. Auge, J. (2011). Les su- cres solubles, une opportunité pour l'agriculture durable. Phytoma- la défense des plantes, 640, 10-14. Derridj, S., Lombarkia, N., Garrec, J. P., Galy, H., and Ferré, E. (2012). Sugars on leaf surfaces used as signals by the insect and the plant: implications in orchard protection against Cydia pomonella L. (Lepidoptera, Tortricidae), in Moths: Types, Ecological Significance and Control, ed. by Cauter- rucio L. Nova Science Publishers Inc., Hauppage, NY, pp. 1-38 Korbon, S.S., 2021. The Apple genome. Ed. Springer Nature Switzerland AG. 412 p. Kuyulu, A. and Genç, H., 2019. Biology and laboratory rearing of codling moth, Cydia pomonella (L.) (Lepidoptera: Tort- ricidae) on its natural host "green immature apple" Malus domestica (Borkh.) (Rosales: Rosaceae). Turkish Journal of Agricultural and Natural Sciences, 6(3), 546-556. Lombarkia, N. (2002). Influence de métabolites présents à la surface des organes du pommier sur la ponte du carpocapse: Cydia pomonella L. (Lepidoptera: Tortricidae). Application à l'étude de la résistance du pommier au ravageur. Doctoral dessertation. Université Rennes 1, France. Lombarkia, N. and Derridj, S. (2008). Resistance of apple trees to Cydia pomonella egg-laying due to leaf surface metabo- lites. Entomologia Experimentalis et Applicata, 128, 57-65. https://doi.org/10.1111/j.1570-7458.2008.00741.x Lombarkia, N., Derridj, S., Ioriatti, C., and Bourguet, E. (2013). Effect of a granulovirus larvicide, Madex®, on egg-laying of Cydia pomonella L. (Lepidoptera: Tortricidae) due to changes in chemical signalization on the apple leaf sur- face. African Entomology, 21(2), 196-208. https://doi. org/10.4001/003.021.0212 Meradi, R. (2015). Utilisation des sucres et de virus de la granu- lose dans la potection des pommiers contre le carpocapse Cydia pomonella L. (Lepidoptera, Tortricidae) dans la ré- gion de Limbiridi (Wilaya de Batna). Magister dissertation. Institut d'Agronomie, Université de Batna, 84 p. Nasri, A. (2015). Utilisation des sucres et virus de la granulose pour la lutte contre le carpocapse Cydia pomonella L. (Lepi- doptera, Tortricidae) en verger de pommier situé dans la ré- gion d'Ain-Touta (Wilaya de Batna). Magister dissertation, Institut d'Agronomie, Université de Batna, 79 p. Pajač, Živković, I., Benitez, H.A., Barić, B., Drmić, Z., Kadoić Balaško, M., Lemic, D., Dominiguez, Davila, J.H., Mikac, K.M. and Bažok, R. (2019). Codling moth wing morphol- ogy changes due to insecticide resistance. Insects, 10(10), 310. pp 1-13. https://doi.org/10.3390/insects10100310 Ramadan, M. F., and Farag, M. A. 2022. Mediterranean Fruits Bio-wastes. Chemistry, Functionality and Technological Applications. Ed. Springer Nature Switzerland AG. 855 p. https://doi.org/10.1007/978-3-030-84436-3 Rodríguez, M.A., Marques, T., Bosch, D., and Avilla, J. (2011). Assessment of insecticide resistance in eggs and neonate larvae of Cydia pomonella (Lepidoptera: Tortricidae). Pesti- cide Biochemistry and Physiology, 100(2), 151-159. https:// doi.org/10.1016/j.pestbp.2011.03.003 Rodríguez, M.A., Bosch, D., and Avilla, J. (2012). Azinphos- methyl and carbaryl resistance in adults of the codling moth (Cydia pomonella (L.), Lepidoptera: Tortricidae) from North eastern Spain. Pesticide Biochemistry and Physiolo- gy, 103, 43-48. https://doi.org/10.1016/j.pestbp.2012.03.002 Sauphanor, B., Berling, M., Toubon, J. F., Reyes, M., Delnatte, J., and Allemoz, P. (2006). Carpocapse des pommes cas de résistance au virus de la granulose en vergers biologiques: Fruits et légumes. Phytoma, la Défense desVégétaux, 590, 24-27. Tarkowski, L.P., Poel, B.V., Höfe, M., and Ende, W.V. (2019). Sweet immunity: Inulin boosts resistance of lettuce (Lactu- ca sativa) against grey mold (Botrytis cinerea) in an ethyl- Acta agriculturae Slovenica, 120/4 – 20246 A. K. TIFFRENT et al. ene dependent manner. International Journal of Molecular. Sciences, 20, 1-22. https://doi.org/10.3390/ijms20051052 Tiffrent, A. and Lombarkia, N. (2021). Assessement of con- trol strategy by spraying low doses of sugars on apple orchards against Cydia pomonella (L.), Acta Agricultu- rae Slovenica, 117(1), 15-20. https://doi.org/10.14720/ aas.2021.117.1.1740 Tiffrent, A. and Lombarkia, N. (2022a). Effect of the exogenous foliar sprays of micro-doses of fructose and glucose on egg- laying of Cydia pomonella L. and its oviposition site selec- tion in apple orchard. Journal of Bioresource Management, 9(4), 85-91. Tiffrent, A. and Lombarkia, N. (2022 b). Effect of foliar applica- tion of glucose and fructose to reduce codling moth (Cydia pomonella [L., 1758]) damages on apple orchard, Acta Ag- riculturae Slovenica, 11(4), 1-6. https://doi.org/10.14720/ aas.2022.118.4.2515 Whalon, M.E., Mota-Sanchez, D., and Hollingworth, R.M. (2008). Global pesticide resistance in ar- thropods. CAB International, 169 p. https://doi. org/10.1079/9781845933531.0000 Walters, D. R., Ratsep, J., and Havis, N. D. (2013). Controlling crop diseases using induced resistance: challenges for the future. Journal of experimental botany, 64(5), 1263-1280. https://doi.org/10.1093/jxb/ert026