Susceptibility of Ceratitis capitate (Wiedemann) To Native and Imported Entomopathogenic Nematodes and Compatibility with Abamectin and Fenamiphos

ABSTRACT


INTRODUCTION
The Mediterranean fruit fly, Ceratitis capitata Wiedemann, 1824 (Diptera: Tephritidae), is recognized as the most disturbing and damaging fruit fly pest worldwide that reduced the production and quality of more than 360 different hosts ranging from citrus to soft and stone fruits and vegetables (Liquido et al., 1991;Papadopoulos et al., 1998;Satar et al., 2016). C. capitata can tolerate climatic conditions better than most other fruit flies, negatively impacting global fruit production. A successful integrated pest management (IPM) strategy uses a combination of natural enemies of pest arthropods and other alternative Infectivity of two native Egyptian isolates belonging to Heterorhabditis spp. was evaluated against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), compared with imported Steinernema and Heterorhabditis species by two laboratory assays and compatible responses with recommended application concentration (RC) and 0.5 RC of abamectin and fenamiphos. The efficacy of EPNs is directly associated with an increase in concentrations, and percentages of mortalities were higher in the third larvae stage than in the pupal stage. Moreover, native H.bacteriophora (Ar-4 strain) caused the high mortality rates of imported H.bacteriophora (HP88 strain).At concentration 200 IJs/ larvae or pupa, S. feltiae (Filipjev) showed the shortest median lethal time (LT50) for the killing of medfly with LT50 1.19 days in third-instar larvae and 1.26 days with pupae of C. capitata followed by S. glaseri (NC strain) and S. carpocapase (All strain). On the other hand, native H. bacteriophora (Ht strain) caused the least larvae and pupae mortalities compared to other Egyptian isolates, H. bacteriophora Ar-4 strain with LT50 2.25 days and 2.38 days in larvae and pupal stage with mentioned concentration, respectively. Regarding the compatibility of abamectin and fenamiphos with EPN species, incompatible responses were revealed with the RC of abamectin. In contrast, an additive effect was exhibited by combining EPN species and 0.5 RC of the tested nematicides. Also, larvae of medfly showed a compatible interaction (additive) when compared with the pupal stage, and H.bacteriophora (Ar-4 strain) was more compatible with two nematicides compared to H.bacteriophora (Ht strain). Current results indicate the feasibility of the integrated management of EPNs with a low dose of chemical pesticides in crop protection. measures that play significant roles in crop protection. Also, it minimized pesticides' negative environmental impacts and other deleterious effects while providing a more sustainable approach to pest control.
Several microbial control agents, such as viruses, bacteria, fungi, and nematodes, offer effective control that can be combined with other tactics. Moreover, they are safe for the environment, beneficial insects, applicators, and the food supply, and they can be applied just before field fruit harvest (Kaya & Lacey, 2007).
Laboratory and field studies assessed numbers of natural enemies, including parasitoids that can use their ovipositor to locate and parasitize medfly eggs and larvae within the fruit but are protected from entomopathogens and only entomopathogens including entomopathogenic nematodes (EPNs) (Bazman et al., 2008;Gazit et al., 2000;Lindegren and Vail, 1986;Lindegren et al. 1990) or fungi (Ekesi et al., 2007) could infect larvae during leave the fruit and enter the soil. To date, 16 out of 117 currently described EPN species (12 Steinernema and 4 Heterorhabditis) (Shapiro-Ilan et al., 2018), besides additional isolates and species, remain undescribed.
C. capitata is one of numerous soil insect pests successfully candidates for biological control by ENPs belonging to families of steinernematidae and heterorhabditidae, which are associated with mutualistic bacteria belonging to the genus Xenorhabdus in the genus Steinernema and Photorhabdus in the genus Photorhabdus respectively. The bacterial cells are carried as symbionts in the intestinal tract of the only free-living stage of the nematode, the infective juvenile (IJ) . Most applied EPN imported abroad and with several species isolated from Egyptian soils (El-Ashry et al., 2018;Alexandros Dritsoulas et al.,2022).
Laboratory control studies have been conducted on medflies (Gazit et al.,2000;Karagoz et al.,2009;Minas et al.,2016;Mokrini et al.,2020;Kapranas et al.,2021). So, it has been proposed that applying EPNs in the soil beneath the tree canopy can kill a significant number of the soil-dwelling stages of medflies.
In recent studies, different authors elucidated the efficacy of steinernematid and heterorhabditid species against larvae and pupae of C. capitata in reducing population densities in laboratory assays or under field conditions (Mokrini et al.,2020;Kapranas et al.,2021).
In vitro assay helps improve our knowledge about combinations of virulent EPN species (native and imported species) in subsequent field management tactics combination between biocontrol agents used against fruit flies on crops (Hooper et al.,2005;Neumann & Shields, 2008;Finke & Snyder, 2010). However, in vitro assays of previous studies by Aioub et al., 2021 compatible studies showed that the combining effect with various pesticides could be antagonistic, synergistic, or additive with different EPN species.
Therefore, the current study focused on the efficacy of native and imported EPNs as implemented biological control agents with two pesticides used in the control of larvae and pupae of C. capitata in soil under laboratory conditions to improve our knowledge that will increase our understanding of inclusive EPNs as a biocontrol agent in fruit fly IPM programs.

Rearing of Mediterranean Fruit Fly, Ceratitis capitata:
According to (Vargas, 1989), the laboratory culture of C. capitata colony was previously supplied as pupae by Plant Protection Institute in Dokki, Giza, Egypt., and then reared on an artificial diet. Adults of medfly were provided with water and a standard adult diet consisting of a mixture of Brewer's yeast, sugar, and water at a 4:1:5 ratio and reared in wire-screened wooden holding cages (40×40×65 cm) (Pašková, 2007). Eggs were collected from modified oviposition domes and provided with water and (Citrus aurantium L.; Rutaceae) bitter orange juice to stimulate oviposition. Larvae were reared on an artificial diet prepared by mixing 330 g wheat bran, 82.5 g sugar, 82.5 g yeast extract, 4 g citric acid, 4 g sodium benzoate, and 500 ml water (Leftwich et al., 2017). Daily collected eggs from the adult cages were transferred to the artificial diet and reared until the third instar in the laboratory at 25±2ºC and 60±5% RH. Mature larvae or pupae were collected from the artificial diet with a 2 mm diameter sieve for the bioassays Pesticides Used: Two registered commercial formulations of pesticides available in the market and used for controlling insect and nematode pests in Egypt were obtained from the Central Laboratory of Pesticides, Dokki, Giza. The tested pesticides were used in the current study at recommended application rate (RC) and 0.5 RC. One of them was a biopesticide, abamectin (Tervigo 2% SC) was used at the recommended concentration (RC), 3 L/feddan, and 0.5 RC (1.5 L/feddan). In contrast, the other one was organophosphate; fenamiphos (Dento 40%EC) was used at RC 6 L/feddan, and 0.5 RC (3 L/feddan).
EPN species reared in last-instar greater wax moth larvae, Galleria mellonella (L.) (Lepidoptera: Pyralidae), at approximately 24 ±2°C according to procedures described in Kaya and Stock (1997). Infective juveniles (IJs) that emerged from insect cadavers in White traps (White, 1927) were stored in shallow water in transfer flasks at 15°C for up to 7 days before use.

Bioassays Studies:
Two laboratory techniques were conducted to bioassay the native and imported EPNs against larvae and pupae of C. capitata.

A. Plastic Cups Method:
Plastic cups (60 mm diameter × 110 mm high) filled with 180 g of sterilized sand were used. The sand of cups was kept at 10 % moisture and provided 20 individuals of medfly (3 rd larval instars or pupae). To evaluate the efficacy of native EPNs species [H.bacteriophora (Ar-4strain) and H.bacteriophora (Ht strain)] or imported EPNs [Steinernema carpocapsae (All strain), S.feltiae (Filipjev), S. glaseri (NC strain), Heterorhabditis bacteriophora (HP88 strain)], EPNs doses of 100, 150 and 200 IJs/larva or pupa were used in this study. The administered cups were capped by a lid, punctured for aeration, and kept at room temperature (26 ±2ºC). Mortality was recorded daily for seven days after EPNs inoculation; to approve the infection, the dead larvae and pupae that showed typical infection signs were placed in White traps in moisten chamber to approve infection (White, 1927). Emerged adults were counted, and mortality was calculated by subtracting the emerged adults from the initial number of larvae or pupae. The mortality of larvae and pupae and the efficiency of EPNs were also determined according to the following formula: Mortality (%) = Number of dead larvae or pupae (Total number of dead larvae or pupae) The control treatment of C. capitate received the same volume of distilled water used in treatments of C. capitata larvae and pupae and the bioassay was performed twice.

B. Petri Dishes Assay:
Native and imported EPNs were used for the Petri dish assay. Each Petri dish of 9 cm filled with 25 g of dry, autoclaved sand (0.3 to 0.5 mm particle size). About 100, 150, and 200 IJs/Petri dish was used in 1 ml, and each dish introduced 20 healthy medfly larvae or pupae. Control Petri dishes received only distilled water. The medfly mortalities (in larvae or pupae) were recorded daily for seven days. Where mortality percentages were calculated according to the following formula: Mortality (%) = Number of dead larvae or pupae (Total number of dead larvae or pupae) 100 If mortality in the controls is between 5% and 20%, cumulative mortality counts obtained from experiments were corrected for natural mortality using Abbott's formula: Corrected  = X = percentage mortality in the treated sample, and Y = percentage mortality in the control. As well as, the median lethal Dose (LD 50 ) and lethal Time (LT 50 ) of nematodes were estimated. Dead larvae and pupae were dissected after mortality.

The Combined Effect of Entomopathogenic Nematodes Abamectin and Fenamiphos Using Plastic Cups Technique:
The biopesticide abamectin and fenamiphos were used to test the combined effect with EPN species. Both nematicides were tested for their effectiveness against larvae and pupae of C.capitata as concomitant treatments (EPNs + RC or 0.5 RC) . Previous plastic cups (60 mm diameter × 110 mm high) filled with 180 g of sterilized sand were used to conduct the bioassay. Each plastic cup with 20 individuals of 3 rd larval stage or pupae treated with 2 ml of tested native or imported EPNs contained 200 IJs and was sprayed immediately with 10 ml of recommended application rate (RC) or 0.5 RC of the tested nematicides. Plastic cups of Medfly stages (larvae or pupae) in control treatments were provided with the same number of larvae or pupae sprayed with 2 ml of distilled water only free of EPNs juveniles or tested concentrations of nematicides.
Medfly mortalities in larvae or pupae were observed and recorded daily for seven days Analysis of the Chemo/Bio-Interaction: Interaction data for mixtures were estimated using Limpel's formula reported by Richer (1987) as follows: The expected additive effect of the mixture. X: The effect is due to component A alone. Y: The effect is due to component B alone.
The expected effect was compared with the actual effect obtained experimentally from the mixture to determine the additive, synergistic or antagonistic effects, according to the equation given by Mansour et al. (1966) as follows: This factor was used to classify results into three categories: ≥ +20 is considered potentiation, ≤ -20, and -20: +20 indicates only additive effect.

Statistical Analysis:
The experiments were carried out in a completely randomized design. Each treatment was replicated five times. Data were subjected to analysis of variance (ANOVA) using MSTAT VERSION 4 (1987). Means were compared by Duncan's multiple range test at P ≤ 0.05 probability.

1-Pathogenicity of Multiple Entomopathogenic Nematode (EPN) Species On C.
Capitata Larvae And Pupae: 1. a: Pathogenicity of Steinernema and Heterorhabditis species/ isolates on C. capitata larvae and pupae: Imported three Steinernema species [S. carpocapse (All strain), S. fetltiae (Filipjev) and S. glaseri (NC strain)] and two imported Heterorhabditis species, H. bacteriophora (HP88 strain) besides two Egyptian Heterorhabditis isolates (Ar-4 strain and Ht strain) were screened by plastic cups methods against medfly, C. capitata larvae (3 rd instar) and pupae to identify their virulence under laboratory condition. In this assay, three doses of 100, 150, and 200 IJs/larvae or pupa were tested to assess the LD50 (lethal dose concentration able to kill 50% of tested larvae or pupae).
From current results, LD50 decreased gradually by increasing doses of EPN species and varied according to EPN species/isolates and medfly stages.
*Each value is a mean of five replicates with 20 medfly larvae or pupae. **Tested medfly larvae /pupae were observed for seven days.
In plastic cup analysis, results displayed that the species of Steinernema belonging to EPNs were more virulent than Heterorhabditis species and showed the least LT50 (lethal time required for killing of 50% larvae or pupae treated with 200IJs), particularly when compared with two native H. bacteriophora (Ar-4 strain) and H. bacteriophora (Ht strain). For instance, LT50 (After four days) with S. carpocapse (All strain), S. fetltiae (Filipjev), and S. glaseri (NC strain) were 1.87, 1.19, and 1,50 days with larvae and 2.05,1.26 and 1.65 days with medfly pupae. LT50 with imported H. bacteriophora (HP88 strain) was 1.50 and 1.65 with 3ed instar and medfly pupae, respectively. On the other hand, native H. bacteriophora (Ar-4 strain) and H. bacteriophora (Ht strain) were less virulent against medfly, C. capitata larvae, and pupae. For instance, LT50 were 2.25 & 2.71 with larvae and 2.38 &2.70 with pupae of medfly treated with H. bacteriophora (Ar-4 strain) and H. bacteriophora (Ht strain), respectively. As Fig. (1) illustrates, larvae were more sensitive to EPNs, and Steinernema species were more virulent against medfly larvae and pupae than Heterorhabditis species. Moreover, native Heterorhabditis species were less aggressive than imported H. bacteriophora (HP88 strain).

Mortality Percentages (%) Of EPN Species at Different Concentrations Against Larvae and Pupae of Ceratitis capitata in Plastic Cups:
In all treatments (larvae/pupae) tested concentrations (100,150, and 200 IJs) against medfly, C. capitata were more effective than controls. Moreover, as the concentration of tested EPNs increased in steinernematid and heterorhabditid species, the mortality rate of the larvae and pupae individuals increased in direct proportion (p < 0.05).
The highest mortality rate detected at a concentration of 200 IJs/larvae or pupae against medfly and S. feltiae (Filipjev) (Table 2). In general, all steinernematid species and imported H. bacteriophora (HP88 strain) were more effective against larvae and pupae of C. capitata at all tested concentrations (100, 150 and 200 IJs) than the two native heterorhabditid species, H. bacteriophora (Ar-4strain) and H. bacteriophora (Ht strain). General percentage mortalities in larvae and pupae of medfly in plastic cup method after 48 and 96 hr illustrated in (Fig.2a &b). Among Heterorhabditis species /isolates, one native (H. bacteriophora Ar-4 strain) and three imported Steinernema species (S. carpocapsae All strain, S. feltiae (Filipjev) and S. glaseri NC strain had excellent performances against 3 rd instar larvae of medfly, and pupae achieved more efficacy against larvae than pupae. Moreover, the H. bacteriophora HP88 strain, followed by the native H. bacteriophora Ar-4 strain, exhibited good performances with insignificant differences (p < 0.05) with the imported H. bacteriophora HP 88 strain. At the same time, the native H. bacteriophora Ht strain was the least efficient isolate.

Mortality Percentages (%) of EPN Species at Different Concentrations Against Larvae and Pupae of C. capitata in Petri Dishes:
The percentage of mortalities obtained from the Petri dishes assay was less than those of plastic cups with larvae and pupae of medfly at the three tested concentrations. As mentioned before with the plastic cups assay, as the concentration of tested EPNs increased in steinernematid and heterorhabditid species, the mortality rate of the larvae and pupae individuals increased in direct proportion (p < 0.05).
The concentration of 200 IJs/larvae or pupae exhibited the highest mortality rate against medfly, and S. feltiae (Filipjev) (Table 3). Generally, steinernematid species and imported H. bacteriophora (HP88 strain) were more effective against larvae and pupae of medfly at concentrations of 100, 150 and 200 IJs than the two native heterorhabditid species, H. bacteriophora (Ar-4strain) and H.bacteriophora (Ht strain).
Whereas, combined application between EPN species and 0.5 RC of abamectin and EPNs in plastic cups assay against pupae of medfly after three days post-treatment exhibited incompatible reaction (antagonism) with EPN species except with S.carpocapase (All strain) and S.feltiae (Filipjev) which showed additive effect (Table 4).

Abamectin and EPN Species/Strains with Larvae:
The compatible response appeared with all EPN species and RC treatments or 0.5 RC of abamectin treatments in plastic cups. Utilization of 0.5 RC of abamectin was more compatible than RC application against medfly third instar larvae. The high additive response appeared with H. bacteriophora (HP88 strain) followed by H. bacteriophora (Ar-4 strain), S.carpocapase (All strain), and S.feltiae (Filipjev), respectively, with 0.5 RC application of abamectin. Although additive response exhibited with RC of abamectin, native heterorhabditid species, H. bacteriophora (Ar-4 strain) and H. bacteriophora (Ht strain) were less compatible with CF of -18.34 and -7.79 when compared with Steinernema species, S.carpocapase (All strain) and S.feltiae (Filipjev), with CF -8.68 and -9.44, respectively (Table5). Table 5. Interaction responses between half recommended application rate of abamectin and different EPNs strains on mortality of C. capitata larvae (3 rd instars) in the plastic cups method after three days of application.

Tervigo and EPN Species/Strains: Various Interactions Between Larvae of Medfly and Tervigo with Larvae:
Antagonism effect exhibited with RC of fenamiphos and S. feltiae (Filipjev), S.glaseri (NC strain) against larvae of medfly, C. capitata whereas additive effect appeared in treatment of combination between RC of fenamiphos and S.carpocapase (All strain). Also, native heterorhabditid species, H.bacteriophora (Ar-4 strain) and H. bacteriophora (Ht strain) showed incompatible reactions with RC of fenamiphos. Only H. bacteriophora (HP88 strain) showed additive effects when combined with RC of fenamiphos three days post-treatment.
On the other hand, the application of 0.5 RC of fenamiphos in the treatment of heterorhabditid species, H.bacteriophora (HP88 strain), H. bacteriophora (Ar-4 strain), and H .bacteriophora (Ht strain) revealed additive effect as well as steinernematid species, S. carpocapase (All strain) only (Table 6). With the recommended dose of fenamiphos, compatibility and incompatibility effects were assessed with EPNs against medfly pupae three days post-treatment. For instance, S. carpocapase (All strain), H. bacteriophora (HP88 strain) and H. bacteriophora (Ar-4 strain) showed additive effect (compatibility) with RC of fenamiphos whereas S.feltiae (Filipjev), S.glaseri (NC strain) and H. bacteriophora (Ht strain) exhibited antagonism (incompatible) response (Table 7). On the other hand, using 0.5 RC of fenamiphos with EPN species revealed an additive response with all EPN species except with S. feltiae (Filipjev).

DISCUSSION
EPN species varied in their efficacy against larvae and pupae of C. capitata. Among evaluated the six species/isolates, only the native Heterorhabditis species, H. bacteriophora (Ht strain), caused the least larvae and pupae mortalities and 5 EPN species had varied mortality rates between moderate and higher mortalities than 60% after four days, namely S. carpocapase (All strain), S. feltiae (Filipjev), S. glaseri (NC strain), H. bacteriophora (HP88 strain) and H. bacteriophora (Ar-4 strain).
The specificity of EPN species against larvae or pupae of medfly cannot be clarified based on a single trait since a diversity of factors act upon that relationship. Specificity is directly associated with EPN's efficiency in locating, infecting, developing, and reproducing without being recognized by the host's immune system (Rohde et al.,2012). Moreover, most C. capitata larvae exposed to the tested EPNs died during the pupal stage, and no essential differences between the genera studied against C. capitata larvae or pupae as well, as native Heterorhabditis isolates also caused the lowest mortalities against the pupal stage.
Moreover, only native isolate, H. bacteriophora (Ar-4 strain), caused the highest mortality rates belonged to Heterorhabditis, and nearby all Steinernema species, S. carpocapase (All strain), S. feltiae (Filipjev) and S. glaseri (NC strain) showed high efficacy with insignificant differences between each other.
Based on LT50, S. feltiae (Filipjev) showed the least L T50 (1.19 days) with thirdinstar larvae and 1.26 days with pupae of C. capitata, followed by S. glaseri (NC strain) and S. carpocapase (All strain) and also, higher susceptibility of the third-instar larvae of C. capitata was obtained at infection with Heterorhabtitis species at least time with imported species H. bacteriophora HP88 strain (1.38 with larvae and 1.50 with pupal stage) while LT50 scored with the native isolate, H. bacteriophora Ar-4 strain were 2.25 and 2.38 days with larvae and pupal stage, respectively.So, the mortality of C. capitata larvae/pupae in the soil increased proportionally to the nematode dose (LD 50) with the least time to kill 50% (LT50) of larvae and pupal stage of medfly, C. capitata.
Results revealed that S. carpocapase (All strain), S. feltiae (Filipjev), and S. glaseri (NC strain) produced mortalities higher than Heterorhabditis species under laboratory and field conditions, particularly with native isolates, and these findings are in agreement with Lindegren, 1990 andRohde et al.,2012. In laboratory assays, plastic cups exhibited the greatest control against larvae and pupae of medfly than Petri dishes assay. Many factors significantly affect EPNs efficacy against medflies, like soil humidity and optimum temperature. Kapranas et al.,2021 mentioned that higher virulence of EPN species against medfly stages due to moderate temperatures (~ 20°C), which could provide control over four weeks and better adapted to lower temperatures species such as S. carpocapsae and S. feltiae is suitable for reproduction (Grewal et al.,1994;Hazir et al.,2001).
Variations in virulence of the same EPNs against the C. capitata stage were noticed in the current assays as observed with S. carpocapsae All strain that exhibited highly virulent C. capitata larvae was probably little effective against the pupal stage because it is an ambusher strategist, making encounters more difficult between pupae (sedentary) and infective juveniles (Rohde et al.,2012).
Many authors as Lewis et al.,2006 mentioned to critical that cruiser strategists of EPN species (i.e., those that actively search for the host) may have a greater probability of finding hosts with cryptic or sedentary habits, while those of ambusher strategists (i.e., those that sit and wait for the hosts in order to attack) are more effective in finding high-mobility hosts. This finding could be attributed to variation in genetics (Gaugler et al., 1989), infectivity (Grifn & Downes,1991), physiology (Fitters et al.,1999), climatic adaptation (Solomon et al.,1999), and morphology (Stock et al., 2000) of different nematode strains of the same species.
The higher susceptibility of larvae over that of pupae to EPNs may be due to their locomotor activity and higher release of CO 2 , which attracts nematodes (Shapiro-Ilan et al., 2017). Moreover, larvae have less sclerotized integuments and large natural openings that facilitate the insect's infection by EPNs (Minas et al., 2016;Rohde et al.,2020). These factors could separately or synergistically increase the susceptibility of larvae to EPNs. Although pupae were less susceptible to EPNs, Chergui et al., 2019 revealed that young pupae of medfly were more susceptible than older pupae due to fewer integuments sclerotized in young pupae than those of older pupae. EPN species can enter young pupae more efficiently, making them more susceptible to infection than older pupae (Godjo et al., 2018).
Compatible pesticides with EPN species could be improved the control strategies against various pests under field conditions after conducting laboratory assays. So, each candidate product used in the IPM system should be tested individually with the specific EPN species or isolates (Krishnayya & Grewal, 2002).
Various combination responses between EPNs and RC or 0.5 RC of abamectin were observed with larvae and pupae of medfly. The current results showed an incomputable reaction between the RC of abamectin and medfly pupae in plastic cups assay. At the same time, RC or 0.5 RC of abamectin showed additive response with the third instar of medfly. These results agree with Mostafa et al.,2022 when examining RC or 0.5 RC of abamectin against two termite species using imported EPN species and two native Heterorhabditis species, H.bacteriophora (Ar-4 strain) and H.bacteriophora (Ht strain). Moreover, the incompatibility effect with Heterorhabditis species and Steinernema species is principally due to the ingredients of abamectin having a well-known nematicide effect (Mahfooz et al.,2008). Moreover, when reduced the dose used (0.5 RC) with some EPN species, i.e., H. bacteriophora (HP88 strain and H. bacteriophora (Ar-4 strain), improved percentage mortalities in larvae of medfly and exhibited an additive effect (Lazinik and Trdan, 2014).
The same trend was observed with RC or 0.5 RC of Tervigo against larvae and pupae of medfly. In joint action between Tervigo and Helicoverpa armigera (Hübner), the highest larval mortality was observed in descending order for combinations between H.bacteriophora (HP88 strain) with fenamiphos (Tervigo) . Moreover, results indicate the feasibility of the integrated management of EPNs and a low dose of chemical pesticides in crop protection.

Conclusion:
All species and strains of EPNs tested were pathogenic to larval and pupal stages of C. capitata. The larval stage of C. capitata was more susceptible to EPNs than pupae. The results found in this study indicate the great potential of the Steinenema species than Heterorhabditis species against two stages of Mediterranean fruit fly. Moreover, the incompatible response of two native isolates of H. bacteriophora with RC of abamectin and Tervigo in plastic cups and Petri dishes assays. However, field studies are needed to confirm the laboratory assays. Also, additional studies are still required to find new isolates of EPNs compatible with pesticides and could tolerate temperate conditions effectively under field conditions.