Impaginato 123 Adv. Hort. Sci., 2020 34(2): 123­132 DOI: 10.13128/ahsc­7835 Growth, yield and fruit quality of tomato under different integrated management options against Tuta absoluta Meyrick A. Ndereyimana 1, 2 (*), S. Nyalala 1, P. Murerwa 1, S. Gaidashova 2 1 Department of Crops, Horticulture and Soils, Egerton University, PO Box 536, 20155 Egerton, Kenya. 2 Department of Agriculture Research and Technology Transfer, Rwanda Agriculture and Animal Resources Development Board, PO Box 5016, Kigali, Rwanda. Key words: azadirachtin, Beauveria bassiana, integrated pest management, Metarhizium anisopliae, Phytolacca dodecandra, Solanum lycoper‐ sicum L., Steinernema, Tephrosia vogelii. Abstract: This study evaluated the effect of entomopathogens and plant extracts, used against Tuta absoluta, on growth, yield, and fruit quality of tomato. Two field trials were carried out in a randomised compled block design, replicated thrice. The treatments were Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), Beauvitech®WP (Beauveria bassiana, Strain J25) as ento­ mopathogens, Tephrosia vogelii and Phytolacca dodecandra as plant extracts, and azadirachtin 0.03% EC. Imidacloprid and water also were included as posi­ tive and negative controls, respectively. The best growth and yield parameters were recorded with the entomopathogens and azadirachtin, which were insignificantly different in most cases. The increase in yied of healthy fruit per plant (average of two trials) compared to the negative control (water spray) was 11.4, 10.8,10.1, 9.6, 3.96, 2.2, 11.7 and 2.4 folds for Steinernema sp. RW14­ M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP, Beauvitech WP, T. vogelii, P. dodecandra, azadirachtin, and imidacloprid, respectively. There was no significant difference in number of leaves per plant and fruit quality parame­ ters. The entomopathogens and azadirachtin, which exhibited a capacity to enhance tomato growth and reduced yield losses due to T. absoluta, are rec­ ommended to be included in integrated pest management programme on tomato. 1. Introduction The increasing world population requires food security, which can be partly achieved by reducing the portion of food lost every year as a result of pests (Kumar and Omkar, 2018). However, yield losses inflicted by crop pests have been observed to increase constantly despite different strate­ gies being implemented globally (Dhaliwal et al., 2010). Tomato (Solanum lycopersicum L.) is one of the most popular vegeta­ (*) Corresponding author: assinapol@gmail.com Citation: NDEREYIMANA A., NYALALA S., MURERWA P., GAIDASHOVA S., 2020 ­ Growth, yield and fruit quality of tomato under different integrated management options against Tuta absoluta Meyrick. ­ Adv. Hort. Sci., 34(2): 123­132 Copyright: © 2020 Ndereyimana A., Nyalala S., Murerwa P., Gaidashova S. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 11 January 2020 Accepted for publication 18 February 2020 AHS Advances in Horticultural Science http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2020 34(2): 123­132 124 bles in the world and its fruits are a rich source of nutrients and health­promoting compounds (Luna­ Guevara et al., 2014; Asensio et al., 2019). One aver­ age­sized tomato fruit offers 40% and 20% of the rec­ ommended daily amount of vitamins C and A, respec­ tively. It also provides a significant amount of dietary fibres and minerals like calcium and potassium (Tigist et al., 2013). Furthermore, the antioxidant activity of ascorbic acid, carotenoids, and phenols protects humans against cancers and cardiovascular diseases (Tigist et al., 2013; Luna­Guevara et al., 2014). Therefore, any technology used on tomato crop has to be investigated not only for its effect on growth and yield but also on fruit quality parameters. Several pests have been reported to attack toma­ to throughout its production cycle (Kumar and Omkar, 2018). The tomato leaf miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), was recognised among the major pests since 1964 in Argentina from where it invaded the rest of South America (Desneux et al., 2010). Following Spain invasion during the year 2006, the pest spread to many other European coun­ tries, the Middle East, more than 40 African coun­ tries, and almost all Southern West and Central Asian countries neighbouring China, the world’s largest tomato producer (Biondi et al., 2018; Mansour et al., 2018). In only one decade, T. absoluta spread drasti­ cally and the world tomato production area under its invasion increased from 3% to 60% (Biondi et al., 2018). In Rwanda, T. absoluta was first recorded in Bugesera District in 2015 (FAO, 2015), after which it quickly spread in all tomato production areas of the country. The damage inflicted by T. absoluta affects negatively its growth and development and can lead to total crop failure (Desneux et al., 2010; Biondi et al., 2018). This calls for concerted efforts from diffe­ rent stakeholders in developing effective manage­ ment strategies against this devastating pest. Synthetic pesticides have been observed to be less effective against T. absoluta (Roditakis et al., 2013) and are associated with various challenges and harmful effects (Brahman et al., 2012; Kumar and Omkar, 2018). The concept of integrated pest man­ agement (IPM) was developed to address the draw­ backs of solely relying on chemical control. In this perspective, alternatives to synthetic insecticides with reduced negative effects have been the object of research in several parts of the world (Biondi et al., 2018). A lot has been done on natural enemies, which are used in biological control of T. absoluta in some parts of the world (Desneux et al., 2010; El­ Ghany et al., 2016; Giorgini et al., 2019). Different biopesticides based on entomopathogens and botan­ ical insecticides have also been evaluated and shown to be effective against this pest. However, these studies have been limited to specific biocontrol strains/species and also have been carried out mainly in the pest’s area of origin (Jallow et al., 2019). Besides, many other studies have been limited to lab­ oratory conditions (Youssef, 2015; El­Ghany et al., 2016; Giorgini et al., 2019). There is also a scarce information on the effects on different T. absoluta management options on growth, yield and fruit quali­ ty of tomato. Entomopathogenic nematodes (EPNs), ento­ mopathogenic fungi (EPFs) and plant extracts (PEs) are among the claimed options for effective manage­ ment of T. absoluta (Mansour et al. , 2018). Laboratory studies in Rwanda recommended some EPNs, EPFs, and PEs which can be advanced to field evaluation stage (Ndereyimana et al., 2019 a, b, c). To this aim, the current study investigated the growth, yield and fruit quality of tomato as affected by entomopathogens and plant extracts against T. absoluta. 2. Materials and Methods Study site This study was carried out in Bugesera District of Rwanda, in a farmer’s field located at 02° 32’ 355” South latitude, 30° 26’ 963” East longitude and an elevation of 1338 m above sea level. The average annual rainfall and temperature are 854 mm and 21.4°C, respectively (Kabirigi et al., 2017). Experimental design, trial establishment, and treat‐ ments application The study evaluated nine treatments in a ran­ domised complete block design with three replica­ tions. The individual experimental plots were 3 m long and 2 m wide, with 1.5 m wide paths between them. Thirty days old, healthy and uniform tomato cv. Roma seedlings were transplanted into the plots applied with 20 t of organic manure per hectare and mulched with dry grass. Transplanting for trials one and two was carried out on 3rd April 2019 and 28th June 2019, respectively. The treatments included: two local EPN isolates (Steinernema sp. RW14­M­C2a­3 and Steinernema sp. RW14­M­C2b­1), two commercial formulations of EPFs [Metatech® WP: Metarhizium anisopliae (Metsch.) Sorok, Strain FCM Ar 23B3, 5 x 109 CFUs/g, Ndereyimana et al. ‐ Different management options against Tuta absoluta in tomato 125 and Beauvitech® WP: Beauveria bassiana (Bals.) Vuill., Strain J25, 1 x 1010 CFUs/g], two local plant extracts (Tephrosia vogelii and Phytolacca dodecan‐ dra), azadirachtin 0.03% EC (Nimbecidine), imidaclo­ prid (Confidor SL 200) and water. The two last treat­ ments were included as positive and negative con­ trols, respectively. The two EPN isolates used were obtained from Biological Control Laboratory ­ EPN Production Facility at Rwanda Agriculture and Animal Resources Development Board (RAB) (Yan et al., 2016). Mass production of the EPNs was done through in‐vivo method using Galleria mellonella lar­ vae (Kaya and Stock, 1997). For field applications, these EPNs were formulated into sponges and were used at a concentration of 5 x 109 IJs/ha (Gözel and Kasap, 2015). The EPF formulations were obtained from Dudutech Division, Flamingo Horticulture (K) Ltd, Naivasha, Kenya and were used at a concentration of 250 g/ha. The two local plant extracts were prepared from leaves of local plants (T. vogelii and P. dodecan‐ dra). The fine powder was obtained (using an electric grinder) from the leaves dried in a shaded area, mixed with boiled water and kept for 12 hours. The concentration used for field application was 15% weight/volume (w/v) and filtration was done using a muslin cloth. Azadirachtin 0.03% EC (Nimbecidine) and imidacloprid (Confidor SL 200) were used at the rates of 5 ml and 1 ml, respectively, per litre of water. All these treatments were applied weekly using a knapsack sprayer and the application volume was 1000 l/ha (Brusselman et al., 2012). Cultural operations Apart from the difference in applied treatments, all other cultural operations were uniformly done in all the experimental plots. Fungicide application was done every week by alternating Copper oxychloride 50% WP with fungicides containing Mancozeb 80% or Mancozeb (640 g/kg) + Metalaxyl (80 g/kg). Each tomato plant was fertilised with 10 g of NPK 17­17­17 as basal fertiliser, supplemented with 4 g of Urea 46% on 30th day after transplanting as per RAB rec­ ommendation. Other cultural practices like watering, weeding, and pruning were carried out conventional­ ly. Data collection and analysis Data were collected on growth, yield, and fruit quality parameters. Plant growth parameters: plant height, stem diameter and number of leaves per plant, were recorded every two weeks. Plant height (cm) was measured from the ground to the tip of each of five randomly selected plants using a metre tape. Stem diameter (mm) was measured from the collar using a digital vernier caliper. The number of leaves arising from the main stem was counted. For yield parameters, the numbers of flower trusses per plant and flowers per truss were recorded 40 days after transplanting, while the number of fruits per truss was recorded 60 days after transplanting. The number and yields of healthy and bored fruits were recorded during the harvesting period, which started 72 and 70 days after transplanting in trials one and two, respectively. All the above parameters were taken from five plants selected randomly in the mid­ dle of each plot. Fruit quality parameters, namely fruit firmness (Kg F/cm2), total soluble solids (TSS) (°Brix), beta­ carotene (mg/100 g of fruit), lycopene (mg/100 g of fruit), and ascorbic acid (mg/100 g of fruit), were recorded. To determine fruit firmness, tomatoes were harvested at the pink stage and stored at room temperature until the uniform red ripe stage. Then, five fruits were randomly selected from each treat­ ment lot and fruit firmness measured in the equatori­ al zone of each tomato using a penetrometer (Ritenour et al., 2002). Total soluble solids were determined on the same fruits used for the determi­ nation of fruit firmness using a refractometer (RHW Refractometer, Optoelectronic Technology Company Limited, UK) (Majidi et al., 2011). Beta­Carotene was obtained following the method described by Delia et al. (2004). Lycopene was extracted using acetone and analysed in a spectrophotometer at 503 nm. Lycopene content was then calculated using the for­ mula given by Ranganna (1997) as follows: Lycopene content = 3.1206 x A x V x D x 100 (W x 100) where A = Absorption, V = Volume made up, D = Dilution, W = Weight of Sample. Ascorbic acid was determined by titration with 2,6­dichlorophenolin­ dophenol dye (AOAC, 1990). The distribution of the collected data was assessed and the appropriate transformation was undertaken, where necessary, before subjecting them to analysis of variance. In both trials, the num­ bers of healthy and bored fruits per plant were square­root transformed, while the yield of healthy and bored fruits per plant were log­transformed. The number of fruits per truss was log­transformed in trial one, and arcsine­transformed in trial two; while the number of flowers per truss was arcsine­ transformed in trial two. All other parameters were Adv. Hort. Sci., 2020 34(2): 123­132 126 Fig. 2 ­ Stem diameter of tomato cv. Roma under different treat­ ments against Tuta absoluta in trials one (A) and two (B). T1: Steinernema sp. RW14­M­C2a­3, T2: Steinernema sp. RW14­M­C2b­1, T3: Metatech®WP (Metarhizium aniso‐ pliae , Strain FCM Ar 23B3), T4: Beauvitech® WP (Beauveria bassiana, Strain J25), T5: Tephrosia vogelii, T6: Phytolacca dodecandra, T7: azadirachtin 0.03% EC, T8: imidacloprid, T9: Water; DAT: Days after transplan­ ting; Different letters above the bars indicate significant difference according to Tukey’s test (p≤0.05). analysed without transformation. To determine the effect of the treatments on tomato fruits yield and quality, analysis of variance was carried out; and the means for significantly different treatments (at P≤0.05) were separated using Tukey’s honestly sig­ nificant difference test. The data analysis was car­ ried out using the Statistical Analysis System pack­ age, SAS software version 9.2 (SAS Institute, 2010). 3. Results Tomato growth parameters Plant height was significantly (P≤0.05) influenced by the studied treatments from 30 days after trans­ planting (DAP) (Fig. 1). In both trials, the plant height was not significantly different at 15 DAT; with an average of 14.9 and 15.3 cm for trials one and two, respectively. Plant height increased with time but became almost constant at 45 DAT. In trial one, there was no significant difference among the ento­ mopathogens (EPNs and EPFs) and azadirachtin on all days of observation. Tephrosia vogelii was not signifi­ cantly different from all the above at 30, 45, and 60 DAT, except Steinernema sp. RW14­M­C2a­3. Lower plant height was recorded with P. dodecandra and the controls, which were insignificantly different. In trial two, plant height did not significantly differ among the treatments, except P. dodecandra and the controls which had lower plant height than others. Stem diameter did not significantly differ among the treatments at 15 and 30 days after transplanting (DAT) in trial one and at 15 DAT in trial two (Fig. 2). In addition, only the stem diameter in the negative con­ trol was significantly lower as compared to the other treatments at 45 DAT in trial one. Phytolacca dode‐ candra and imidacloprid were similar to the negative control, with significantly lower stem diameter (P≤0.05) compared to the other treatments at 60 DAT. For trial two, P. dodecandra and negative con­ trol had significantly lower stem diameter as com­ pared to the other treatments at 30 DAT; but at 60 DAT it was only the negative control which had signif­ icantly lower stem diameter as compared to azadirachtin and all entomopathogens except Beauvitech® WP. The number of leaves per plant was not signifi­ cantly affected by the evaluated treatments in both Fig. 1 ­ Plant height of tomato cv. Roma under different treat­ ments against Tuta absoluta in trials one (A) and two (B). T1: Steinernema sp. RW14­M­C2a­3, T2: Steinernema sp. RW14­M­C2b­1, T3: Metatech®WP (Metarhizium aniso‐ pliae, Strain FCM Ar 23B3), T4: Beauvitech® WP (Beauveria bassiana, Strain J25), T5: Tephrosia vogelii, T6: Phytolacca dodecandra, T7: azadirachtin 0.03% EC, T8: imidacloprid, T9: Water; DAT: Days after transplan­ ting; Different letters above the bars indicate significant difference according to Tukey’s test (P≤0.05). Ndereyimana et al. ‐ Different management options against Tuta absoluta in tomato 127 trials. However, the general trend observed in both trials was that slightly higher (but not significantly dif­ ferent) number could be obtained in plots treated with Metatech® WP (M. anisopliae, Strain FCM Ar 23B3) and azadirachtin in trial one; and with Steinernema sp RW14­M­C2a­3 and Beauvitech® WP (B. bassiana, Strain J25) in trial two (Fig. 3). The aver­ age numbers of leaves per plant recorded at 60 DAT in trial one were 13.0, 12.8,14.0, 12.5, 12.8, 12.6, 13.3, 11.9, and 12.6; while in trial two they were 11.8, 11.6, 11.7, 11.9, 11.1, 11.1, 11.5, 11.2, and 11.3, in plots treated with Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2b­1, Metatech®WP (M. anisopliae, Strain FCM Ar 23B3), Beauvitech® WP (B. bassiana, Strain J25), T. vogelii, P. dodecandra, azadirachtin, imidacloprid, and water, respectively. Effect of entomopathogens and plant extracts on tomato yield The evaluated treatments significantly (P<0.001) influenced tomato yield parameters in both trials (Table 1). Generally, plots treated with the ento­ mopathogens or azadirachtin had higher perfor­ mance as compared to those with plant extracts or controls. A similar number of flower trusses per plant was recorded by Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP, Fig. 3 ­ Number of leaves per plant for tomato cv. Roma under different treatment against Tuta absoluta in trials one (A) and two (B). T1: Steinernema sp. RW14­M­C2a­3, T2: Steinernema sp. RW14­M­C2b­1, T3: Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), T4: Beauvitech® WP (Beauveria bassiana, Strain J25), T5: Tephrosia vogelii, T6: Phytolacca dodecandra, T7: azadi­ rachtin 0.03% EC, T8: imidacloprid, T9: Water; DAT: Days after transplanting; Similar letters above the bars indica­ te non­significant difference according to Tukey’s test (P≤0.05). Table 1 ­ Yield parameters (mean ± SD) of tomato under different entomopathogens and plant extracts treatments T1: Steinernema sp. RW14­M­C2a­3, T2: Steinernema sp. RW14­M­C2b­1, T3: Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), T4: Beauvitech® WP (Beauveria bassiana, Strain J25), T5: Tephrosia vogelii, T6: Phytolacca dodecandra, T7: azadirachtin 0.03% EC, T8: imidacloprid, T9: Water. Means followed by the same letter (s) are not significantly different (Tukey’s test, P≤0.05) Treatments Number of flower trusses/plant Number of flowers/truss Number of fruits/truss Number of healthy fruits/plant Number of bored fruits/plant Yield of healthy fruits (g/plant) Yield of bored fruits (g/plant) Trial one T1 11.9 ± 0.2 a 9.7 ± 0.4 a 4.1 ± 0.3 a 5.9 ± 0.2 a 5.8 ± 0.2 a 406.3 ± 10.9 a 333.3 ± 33.4 a T2 11.6 ± 0.4 abc 8.5 ± 0.1 bc 4.0 ± 0.1 a 5.6 ± 0.2 a 5.1 ± 0.4 a 381.0 ± 22.3 a 286.8 ± 8.8 a T3 11.7 ± 0.2 ab 7.7 ± 0.2 cd 4.1 ± 0.1 a 5.5 ± 0.3 a 6.1 ± 0.4 a 374.4 ± 23.5 a 328.8 ± 34.9 a T4 11.4 ± 0.1 abc 7.3 ± 0.3 de 3.8 ± 0.5 a 5.4 ± 0.2 a 5.6 ± 0.4 a 335.0 ± 34.5 a 313.9 ± 17.3 a T5 10.9 ± 0.2 bc 7.4 ± 0.1 de 3.0 ± 0.3 b 2.5 ± 0.3 b 3.2 ± 0.2 b 151.0 ± 12.3 b 161.7 ± 9.7 b T6 10.8 ± 0.3 c 6.4 ± 0.2 ef 2.9 ± 0.2 b 1.5 ± 0.1 c 2.6 ± 0.2 cb 81.5 ± 12.5 b 126.2 ± 10.1 b T7 12.7 ± 0.1 a 9.4 ± 0.6 ab 4.3 ± 0.2 a 6.5 ± 0.2 a 4.9 ± 0.6 a 402.9 ± 12.7 a 275.7 ± 29.5 a T8 10.8 ± 0.3 c 6.5 ± 0.3 ef 3.0 ± 0.4 b 1.7 ± 0.2 c 2.3 ± 0.5 cb 86.6 ± 9.0 b 109.9 ± 26.2 bc T9 10.8 ± 0.5 c 5.6 ± 0.7 f 2.5 ± 0.3 b 0.7 ± 0.4 d 1.9 ± 0.5 c 32.5 ± 8.2 c 83.7 ± 22.1 2 b CV 2.5 4.89 6.53 4.39 5.76 4.2 2.23 P <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 Trial two T1 9.0 ± 0.2 a 7.7 ± 0.3 a 3.8 ± 0.3 a 5.5 ± 0.2 a 4.6 ± 0.7 a 367.8 ± 5.2 a 249.5 ± 22.1 a T2 9.0 ± 0.2 a 7.4 ± 0.2 a 3.7 ± 0.2 a 5.4 ± 0.2 a 4.7 ± 1.0 a 350.9 ± 12.1 a 255.9 ± 38.1 a T3 8.8 ± 0.2 ab 5.6 ± 0.2 cb 3.8 ± 0.4 a 4.9 ± 0.4 a 5.6 ± 0.8 a 309.7 ± 26.3 a 302.4 ± 45.9 a T4 8.8 ± 0.5 ab 5.5 ± 0.2 cb 3.6 ± 0.2 a 4.9 ± 0.4 a 5.3 ± 1.0 a 319.4 ± 33.5 a 273.6 ± 64.8 a T5 8.8 ± 0.2 ab 5.9 ± 0.2 b 2.8 ± 0.1 b 2.0 ± 0.4 b 4.4 ± 0.4 a 113.1 ± 13.4 b 220.9 ± 18.2 a T6 8.1 ± 0.2 b 5.2 ± 0.3 cb 2.4 ± 0.4 b 1.4 ± 0.2 b 2.1 ± 0.1 b 67.0 ± 8.5 c 114.8 ± 17.0 b T7 9.3 ± 0.2 a 8.0 ± 0.3 a 4.0 ± 0.2 a 6.0 ± 0.4 a 4.7 ± 0.1 a 392.5 ± 38.1 a 266.6 ± 19.6 a T8 8.7 ± 0.1 ab 5.5 ± 0.3 cb 2.7 ± 0.2 b 1.6 ± 0.3 b 1.9 ± 0.5 b 74.7 ± 8.1 c 96.7 ± 22.5 b T9 8.1 ± 0.2 b 5.0 ± 0.2 c 2.2 ± 0.3 b 0.8 ± 0.2 c 1.7 ± 0.2 b 35.7 ± 6.7 d 80.0 ± 10.10 b CV 3.02 2.31 4.17 5.11 7.94 2.3 3.05 P 0.0004 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 128 Adv. Hort. Sci., 2020 34(2): 123­132 Beauvitech WP, and azadirachtin. These values were significantly (P<0.001) higher than T. vogelii, P. dode‐ candra, imidacloprid, and water spray in trial one. In trial two, the effect of T. vogelii and imidacloprid was similar to all the treatments but the plot treated with EPNs and azadirachtin recorded a significantly higher number of flower trusses per plant than the negative control. The number of flowers per truss was signifi­ cantly higher with Steinernema sp. RW14­M­C2a­3 and azadirachtin in trial one, and with all ento­ mopathogenic nematodes and azadirachtin in trial two. Higher numbers of fruits per truss, healthy and bored fruits per plant were recorded with all ento­ mopathogens and azadirachtin, in both trials. A simi­ lar trend was observed in the yield of healthy and bored fruits per plant. Effect of entomopathogens and plant extracts on tomato fruit quality Tomato fruit quality parameters were not signifi­ cantly influenced by the applied treatments against T. absoluta. The results obtained were so close to each other that it is not easy to find any trend amongst the treatments (Fig. 4). The overall average values obtained were 3.2 and 3.3 kg F/cm2 for fruit firmness, 4.2 and 4.4oBrix for TSS, 8.3 and 8.1 mg/100 g of fruit for beta­carotene, 5.4 and 5.5 mg/100 g of fruit for lycopene, 14.36 and 14.6 mg/100 g of fruit for ascorbic acid in trials one and two, respectively. 4. Discussion and Conclusions Scarce studies have been conducted on the effects of entomopathogens and plant extracts on growth, yield and fruit quality of tomato. The signifi­ cant differences observed in plant height and stem diameter could be due to the differences in the effi­ cacy of studied treatments against T. absoluta. The damages inflicted by T. absoluta larvae my have affected the physiological and biochemical reactions of tomato plants, so that plant growth was conse­ quently affected (Desneux et al., 2010). Beauveria bassiana which was reported to exhibit endophytic activity by colonising vascular tissues would be expected to impair the normal plant growth. However, different researchers reported that B. bassiana does not impede tomato growth (Klieber and Reineke, 2016; Allegrucci et al., 2017). On the other hand, since T. vogelii is a rich source of nitro­ gen, fixed through biological nitrogen fixation (Stevenson et al., 2012), more growth would be expected in this treatment compared to the others because nitrogen is more involved in plant growth and biomass production (Larbat et al., 2016). This was, however, not observed in this study and could be explained by the fact that the amount sprayed as an insecticide was too little to have a direct signifi­ cant effect on plant growth. Finally, the insignificant difference in the number of leaves per plant despite the treatments could be because this parameter is associated with the genetic makeup of the plant (Kaushik et al., 2011) and not with cultural practices including pest management. The significant difference in flower­related parameters could also be due to the difference in the efficacy of the studied treatments. By attacking the floral parts, T. absoluta larvae might have dam­ aged some of them before they differentiate into flowers and caused others to drop; which could be the explanation for the flower abortion observed in this study. These results are in agreement with Cherif et al. (2013) who reported that T. absoluta larvae can damage tomato flower parts and cause flower drop. The observed significant difference in yield parameters may also have arisen from the indirect effect of T. absoluta larvae through their feeding Fig. 4 ­ Fruit quality parameters of tomato cv. Roma under diffe­ rent treatment against Tuta absoluta in trials one (A) and two (B). T1: Steinernema sp. RW14­M­C2a­3, T2: Steinernema sp. RW14­M­C2b­1, T3: Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), T4: Beauvitech® WP (Beauveria bassiana, Strain J25), T5: Tephrosia vogelii, T6: Phytolacca dodecandra, T7: azadi­ rachtin 0.03% EC, T8: imidacloprid, T9: Water; Similar let­ ters above the bars indicate non­significant difference according to Tukey’s test (P≤0.05). Ndereyimana et al. ‐ Different management options against Tuta absoluta in tomato 129 activity in leaf mesophyll (Biondi et al., 2018), which might have slowed down the process of assimilates synthesis and partitioning for their utilisation by dif­ ferent plant organs, including flower parts and fruits. In agreement with the above observation, Desneux et al. (2010) and El­Ghany et al. (2016) also reported that a tomato attack by T. absoluta dis­ turbs its normal growth, development and the sub­ sequent yield. Thus, higher numbers of flower truss­ es per plant, flowers per truss and fruits per truss recorded with entomopathogens and azadirachtin suggest that these treatments can reduce tomato yield loss as compared to the plant extracts and the controls (imidacloprid and water spray). In their study, Rab and Haq (2012) found that the number of flowers per truss varied from 17.1 to 30.8 while the number of fruits per cluster was 4.1­6.4 for tomato cv. Roma. However, in the present study, a range of 5.6­9.7 flowers per truss and 2.2­4.3 fruits per truss was obtained. This indicates the ability of T. absoluta to negatively affect the flower and fruit­ bearing capacity of tomato plant. This is one of the reasons for high yield losses frequently observed with T. absoluta infestations (Cherif et al., 2013; Biondi et al., 2018). The higher numbers and yield of healthy fruits that were obtained with EPNs, EPFs, and azadirachtin support our earlier findings in laborato­ ry experiments (Ndereyimana et al., 2019 a, b, c). In line with the findings of this study, Braham et al. (2012), Gözel and Kasap (2015), Youssef (2015), and El­Ghany et al. (2016) reported that EPNs, EPFs, and azadirachtin result in better control of T. absoluta. The performance of plant extracts and imidacloprid (positive control) remained low as it was in our pre­ vious laboratory studies (Ndereyimana et al., 2019 a, b). Negative control also recorded very low yield, which was consistent with Desneux et al. (2011) and Biondi et al. (2018) who emphasized that if there are no serious pest management strategies that are meticulously implemented, the yield loss might reach 100%. Higher number and yield of bored fruits obtained from plots treated with entomopathogens and plant extracts, as compared to plant extracts and controls, might have resulted from the reduced number of aborted and damaged flowers by T. absoluta in the plots where these treatments were applied. Although these fruits survived from early abortion and the dropping of progenitor flowers, they were more exposed to T. absoluta because they were many, and thus a group of them was later bored by the pest that spoiled their quality. Compared to the negative control, the yield of healthy fruits obtained with Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP, Beauvitech®WP, and azadirachtin increased 12.5, 11.7, 11.5, 10.3 and 12.4 folds, respectively. While compared to the posi­ tive control, it was 4.8, 4.5, 4.2, 4.1 and 5.0 folds, respectively. This confirms that, despite the invasive nature of T. absoluta, different management options can reduce significantly its negative impact on the crop. However, dependence on synthetic insecti­ cides should be discouraged as evidenced by the results of this study, which are consistent with sev­ eral other researchers (Desneux et al., 2010; Roditakis et al., 2013; Biondi et al., 2018). The commercial value of bored fruits is lost because they are not preferred by customers as external appearance and absence of defects are among the factors determining consumer preference (Asensio et al., 2019). In addition to the larvae that enter inside the fruits, also some pathogens like fungi often get inside through the created holes and cause fruit decaying before or after harvest (Desneux et al., 2010). The findings of this study are supported by previous researchers who worked on other pests and reported that crop pests are among the main factors reducing the yield and quality of field horticultural produce by direct feeding or by favouring several dis­ eases (Kumar and Omkar, 2018). Thus, implementa­ tion of IPM is worth to ensure better yield and quality of tomato crop. Since the damage inflicted by Tuta absoluta on the leaves of tomato plants negatively affects its physiological processes (Desneux et al., 2010; Biondi et al., 2018) and fruit total soluble solids are translo­ cated from the photosynthetic activities in the leaves (Beckles, 2012), significant difference in fruit quality parameters was expected among treatments with different T. absoluta infestation levels. Similarly, the entomopathogens and azadirachtin that exhibited better T. absoluta control would have also resulted in higher quality fruits as compared to the plant extracts and the controls´ treatments. The observed non­significant difference in tomato fruit quality parameters: firmness, total soluble solids, beta­carotene, lycopene, and ascorbic acid among treatments against T. absoluta, therefore may be attributed to other factors such as variety, crop nutrition, climatic conditions, fruit ripening stage, and storage period (Marsic et al., 2011; Rab and Adv. Hort. Sci., 2020 34(2): 123­132 130 Haq, 2012; Tigist et al., 2013; Asensio et al., 2019). Fruit firmness results obtained in this study fall in the range of the values obtained by Rab and Haq (2012). Fruit firmness is an important quality parame­ ter that determines fruit shelf­life and resistance to mechanical damage (Tigist et al., 2013). In line with the current study, Parmar et al. (2018) also obtained a TSS value of 4.8 oBrix for tomato cv. Roma under organic management system. Also, TSS values obtained by Rab and Haq (2012) ranged from 4.08 to 6.10 oBrix under different rates of calcium chloride and borax. The values of beta­carotene and lycopene recorded in this study are close to what was obtained by Parmar et al. (2018) (8.34 mg/100 g and 5.38 mg/100 g of fruit, respectively) for the same variety (Roma) produced organically. The ascorbic acid results obtained in this study agree with the earlier findings of Tigist et al. (2013) who obtained the val­ ues of 13.2 and 14.8 mg/100 g after four and eight days of room temperature storage, respectively, for Tomato cv. Roma fruits harvested at the green mature stage. According to Tigist et al. (2013), these quality parameters develop into fruit during the pre­harvest period and they do not get improved after harvest­ ing. However, they can be maintained by proper post­harvest handling and storage. Since pre­har­ vest activities are responsible for the development of quality parameters in tomato fruits, any technolo­ gy used to improve its production should also be assessed for its effect on fruit quality. As a conclusion, the studied entomopathogens and plant extracts significantly affected tomato growth and yield but not the fruit quality parame­ ters. Better yield performance can be obtained with the entomopathogenic nematode isolates (Steinernema sp. RW14­M­C2a­3 and Steinernema sp. RW14­M­C2a­3), commercial formulations of entomopathogenic fungi (Metatech®WP: Metarhizium anisopliae, Strain FCM Ar 23B3 and Beauvitech®WP: Beauveria bassiana, Strain J25) and azadirachtin 0.03% EC, which were not significantly different. These biorational control agents are rec­ ommended to be included in the IPM of Tuta abso‐ luta. The results of this study will guide producers to select the best control options that can result in higher comparative growth and yield without com­ promising fruit quality. Further studies should be conducted to confirm the effects of the studied entomopathogens and plant extracts under varied agro­climatic conditions. 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