scholarly journals Virulence of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of Diabrotica speciosa germar (coleoptera: chrysomelidae)

2011 ◽  
Vol 35 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
Viviane Santos ◽  
Alcides Moino Junior ◽  
Vanessa Andaló ◽  
Camila Costa Moreira ◽  
Ricardo Alves de Olinda

Entomopathogenic nematodes (EPNs) are used in biological control of soil insects and show promise in the control of D. speciosa. The objective of this work was to evaluate the potential of native and exotic entomopathogenic nematode isolates in the control of D. speciosa under laboratory and greenhouse conditions. Results showed that all of EPNs caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri (84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis amazonensis RSC05 (78%). There was no effect of the Heterorhabditis sp. RSC01 and S. glaseri isolates on eggs. The maximum mortality of D. speciosa larvae by Heterorhabditis sp. RSC01 was observed at a concentration of 300 IJ/ insect, while by S. glaseri observed the highest mortality at the concentration of 200 IJ/ insect. The Heterorhabditis sp. RSC01 isolate caused over 80% pupal mortality at a concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was affected by temperature. The Heterorhabditis sp. RSC01 isolate caused reduction in larva survival under greenhouse conditions at all of the tested concentrations and there was no difference in mortality among different concentrations of infectid juveniles.

2005 ◽  
Vol 95 (5) ◽  
pp. 473-482 ◽  
Author(s):  
S. Toepfer ◽  
C. Gueldenzoph ◽  
R.-U. Ehlers ◽  
U. Kuhlmann

AbstractEntomopathogenic nematode species available in Europe were screened for their efficacy against both the root-feeding larvae and silk-feeding adults of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Laboratory screening tests were aimed at the selection of candidate biological control agents for the management of this invasive alien pest in Europe. Steinernema glaseri, S. arenarium, S. abassi, S. bicornutum, S. feltiae, S. kraussei, S. carpocapsae and Heterorhabditis bacteriophora were studied to determine their virulence against third instar larvae and adults of D. v. virgifera in small-volume arenas (using nematode concentrations of 0.5, 0.8, 7.9 and 15.9 infective juveniles cm–2). All nematode species were able to invade and propagate in D. v. virgifera larvae, but adults were rarely infected. At concentrations of 7.9 and 15.9 cm–2, S. glaseri, S. arenarium, S. abassi and H. bacteriophora caused the highest larval mortality of up to 77%. Steinernema bicornutum, S. abassi, S. carpocapsae and H. bacteriophora appeared to have a high propagation level, producing 5970±779, 5595±811, 5341±1177 and 4039±1025 infective juveniles per larva, respectively. Steinernema glaseri, S. arenarium, S. feltiae, S. kraussei and H. bacteriophora were further screened at a concentration of 16.7 nematodes cm–2 against third instar larvae in medium-volume arenas (sand-filled trays with maize plants). Heterorhabditis bacteriophora, S. arenarium and S. feltiae caused the highest larval mortality with 77±16.6%, 67±3.5%, and 57±17.1%, respectively. In a next step, criteria for rating the entomopathogenic nematode species were applied based on results obtained for virulence and propagation, and for current production costs and availability in Europe. These criteria were then rated to determine the potential of the nematodes for further field testing. Results showed the highest potential in H. bacteriophora, followed by S. arenarium and S. feltiae, for further testing as candidate biological control agents.


Author(s):  
Maguintontz Cedney Jean-Baptiste ◽  
Andressa Lima de Brida ◽  
Daniel Bernardi ◽  
Sérgio da Costa Dias ◽  
Juliano de Bastos Pazini ◽  
...  

Abstract The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) is among the main pests of fruit crops worldwide. Biological control using entomopathogenic nematodes (EPNs) may be an alternative to suppress populations of this pest. Thus, the aim of this study was to evaluate the pathogenicity and virulence of six EPN isolates (Heterorhabditis bacteriophora HB, H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47, and S. brazilense IBCB-n06) against C. capitata pupae. The compatibility of EPNs with different chemical insecticides that are registered for management of C. capitata was also assessed. Isolates of H. bacteriophora HB and S. brazilense IBCB-n06 at a concentration of 1,000 infective juveniles (IJ)/ml proved to be most pathogenic to C. capitata (70 and 80% mortality, respectively). In contrast, the isolates H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47 provided pupal mortality of less than 60%. Bioassays to determine lethal concentrations indicated that concentrations of 600 IJ/ml (H. bacteriophora HB) and 1,000 IJ/ml (S. brazilense IBCB-n06) showed the highest virulence against C. capitata pupae. In contrast, the highest numbers of IJs emerged at concentrations of 1,200 and 200 IJ/ml. In compatibility bioassays, malathion, spinetoram, phosmet, acetamiprid, and novaluron were considered compatible with and harmless (Class 1) to H. bacteriophora HB and S. brazilense IBCB-n06, according to IOBC/WPRS. This information is important for implementing integrated management programs for C. capitata, using biological control with EPNs, whether alone or in combination with chemical insecticides.


2021 ◽  
Vol 37 ◽  
pp. e37047
Author(s):  
Sandra Mara Chaneiko ◽  
Andressa Lima de Brida ◽  
Daniel Bernardi ◽  
Luis Garrigós Leite ◽  
Flávio Roberto Mello Garcia

Anastrepha fraterculus (Wiedemann) is one of the main pests of fruit farming, and entomopathogenic nematodes (EPNs) represent an important control tool of this species. Thus, the objective of this study was to evaluate the biological activity of different isolate against A. fraterculus larvae and adults. Bioassays were performed using a suspension of three isolates of Heterorhabditis amazonensis IBCB 24, Steinernema carpocapsae IBCB 02 and Steinernema feltiae IBCB 47 at six concentrations (control - without nematodes), 50, 150, 300, 500, 1000 and 1500 infective juveniles (IJs)/mL of water per 3º instar larvae. It was verified the susceptibility of larvae of A. fraterculus to isolates of EPNs and a significant increase of the pupal mortality in the function of the concentration of IJs inoculated by larva (above 75%). After the dissection of pupae and adults of A. fraterculus from infected larvae, the concentration of 1500 IJs/mL of EPNs provided the highest rate of multiplication of IJs by insect, equating to maximum concentration tested 1500 IJs/mL. Adults of A. fraterculus from larvae infected with EPNs longevity of five days, being less than adults from uninfected larvae by IJs (135 days). H. amazonensis IBCB 24, S. carpocapsae IBCB 02, and S. feltiae IBCB 47 proved to be promising as agents of biological control of A. fraterculus.


Nematology ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Chau N. Nguyen ◽  
Anh T. Do ◽  
Phap Q. Trinh ◽  
Phuc K. Hoang

Summary The virulence and efficacy of two species of entomopathogenic nematodes, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), against nymphs of the coffee cicada, Dundubia nagarasingna, was evaluated under laboratory and glasshouse conditions. The highest mortality rates of coffee cicada nymphs caused by these two nematode strains were 93.5 and 100%, respectively, at an inoculation dose of 600 infective juveniles (IJ) nymph−1. The virulence (LC50) was established as 137.5 IJ and 149.1 IJ for strains S-PQ16 and H-KT3987, respectively. The highest IJ yields of these nematode strains were 66 × 103 IJ (for S-PQ16) and 134.4 × 103 IJ (for H-KT3987) at a dose of 500 IJ nymph−1. The efficacies of the two nematode strains to coffee cicadas at treated dose of 60 × 103 IJ pot−1 were 84.4 and 88.9% after 30 days, higher than the efficacies at treated dose of 40 × 103 IJ pot−1. The number of IJ in 250 ml of soil at 10, 20 and 30 days after treatment, increased from 0.38 × 103 to 4.80 × 103 IJ in soil treated with a dose of 40 × 103 IJ and from 0.66 × 103 to 5.02 × 103 IJ in soil treated with a dose of 60 × 103 IJ (for S-PQ16). Similarly, for H-KT3987 the number of IJ increased from 0.43 × 103 to 8.99 × 103 IJ and from 0.62 × 103 to 9.64 × 103 IJ, at the respective doses. Based on results of a pot trial from glasshouse modelling, an IJ application dosage for biological control of coffee cicada nymphs in coffee plantations was proposed.


Author(s):  
Américo de Castro Monteiro Sobrinho ◽  
Isadora Luiza Alves Costa ◽  
Graziele Calixto Souza ◽  
Luís Carlos de Souza Rodrigues Leal ◽  
João Luiz Lopes Monteiro Neto ◽  
...  

Abstract Stomoxys calcitrans is a hematophagous dipteran. Several agents are used in biological control, including entomopathogenic nematodes (EPNs). Bioassay I involved an evaluation of the effect of Heterorhabditis bacteriophora HP88 and Heterorhabditis baujardi LPP7 on S. calcitrans larvae in different periods of exposure. Groups of 10 larvae were placed in Petri dishes and 200 EPNs/larva were added, which were divided into groups according to the exposure times of 2, 4, 6, 12, 24 and 48 hours. The purpose of Bioassay II was to evaluate the efficacy of the EPNs in infecting S. calcitrans larvae when they were isolated from stable fly larvae in Bioassay I. Groups of 10 larvae were placed in Petri dishes and 200 EPNs/larva were added. In bioassay I, H. bacteriophora caused mortality rates of 51.7, 83.3 and 91.7% in 12, 24 and 48 hours, respectively, while H. baujardi caused mortality rates of 9.3 (12h), 35 (24h) and 35% (48h). In Bioassay II, H. bacteriophora and H. baujardi resulted in mortality rates of 35% and 25%, respectively. It was concluded that the longest exposure times presented the highest larval mortality and that EPNs isolated from S. calcitrans are not efficient in controlling the larvae fly.


Nematology ◽  
2009 ◽  
Vol 11 (3) ◽  
pp. 365-373 ◽  
Author(s):  
Ana Morton ◽  
Fernando García-del-Pino

AbstractThe virulence of 14 Steinernema feltiae isolates, one S. carpocapsae and three Heterorhabditis bacteriophora isolates was compared in the laboratory against larvae, pupae and adults of the flatheaded root borer, Capnodis tenebrionis. Larval mortality ranged from 50 to 100% and pupae mortality from 0 to 70%. Adults were exposed to different nematode concentrations, 50 and 100 infective juveniles/cm2. Steinernema feltiae caused the highest mortality at the two doses tested, reaching 66.7% and 100%, respectively. Significant differences in mortality between C. tenebrionis males and females were observed. The differences in virulence observed at each stage of C. tenebrionis vary within a species and can be higher than differences among species. The results of this study suggest that some of the isolate strains have potential for improved biological control of C. tenebrionis.


2013 ◽  
Vol 80 (2) ◽  
pp. 237-241 ◽  
Author(s):  
R. Cardoso ◽  
C. M.O. Monteiro ◽  
M.C.A. Prata ◽  
E.S.P. Batista

This work evaluated the in vitro effects of Steinernema glaseri on the biology of engorged Amblyomma cajennense nymphs. The ticks were exposed to infective juveniles (IJs) of S. glaseri at different concentrations. Each treatment was composed by 10 experimental units (EU = repetitions) in Petri dishes maintained at 27 ± 1º C and relative humidity (RH) > 80 ± 10% for 72 hours. Then the nymphs were transferred to Petri dishes free of nematodes for observation of the following parameters: pre-ecdysis period (PEP), ecdysis period (EP), molting period (MP), ecdysis percentage (%Ec) and mortality percentage (%Mt). The groups treated with 5,000 and 10,000 IJs/EU showed significant alterations in the PEP when compared to the control, while for the EP only the treatment with 10,000 IJs/EU produced any significant changes compared to the control. The MP did not differ significantly from the control in any of the treated groups. For the %Ec only the group treated with 10,000 IJs/EU differed significantly from the control. The greatest efficiency was obtained at the concentration of 10,000 IJs/EU, in which the mortality percentage was 13%. This demonstrates that the nematode utilized was not able to cause high mortality in engorged A. cajennense nymphs and agrees with other reports indicating that immature ticks are not highly susceptible to entomopathogenic nematodes.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Camila C. Filgueiras ◽  
Denis S. Willett

AbstractEntomopathogenic nematodes are typically considered lethal parasites of insect hosts. Indeed they are employed as such for biological control of insect pests. The effects of exposure to entomopathogenic nematodes are not strictly limited to mortality, however. Here we explore non-lethal effects of exposure to entomopathogenic nematodes by introducing the relatively non-susceptible pupal stage of Delia antiqua to thirteen different strains. We specifically chose to inoculate the pupal stage because it tends to be more resistant to infection, yet resides in the soil where it could come into contact with EPN biological control agents. We find that there is no significant mortality at the pupal stage, but that there are a host of strain-dependent non-lethal effects during and after the transition to adulthood including altered developmental times and changes in risk of death compared to controls. We also find that exposure to specific strains can reduce risk of mortality. These results emphasize the strain-dependent nature of entomopathogenic nematode infection and highlight the positive and negative ramifications for non-lethal effects for biological control of insect pests. Our work emphasizes the need for strain-specific screening of biological control agents before wide-spread adoption.


2019 ◽  
Author(s):  
Brice G. Sinhouenon ◽  
Hugues Baimey ◽  
Laura Wauters ◽  
Rufin Dossou ◽  
Regis B. Ahissou ◽  
...  

Description of the subject. The article deals with the study of compatibility of entomopathogenic nematode (EPN) species with insecticides currently used against diamondback moth (DBM) Plutella xylostella (L.) in northern Benin Objectives. The aim of this work was to determine the impact of five insecticides on the efficacy of entomopathogenic nematodes against DBM larvae. Method. Infective juveniles (IJs) of two EPN species (Steinernema sp. 83a and Heterorhabditis sonorensis KF723827) were exposed to five insecticides used against P. xylostella larvae in Djougou for 48 h. The number of surviving nematodes was used to infest DBM larvae. The experiment was carried out under laboratory and semi-field conditions. Results. The bioassays carried out in laboratory showed that the survival rate of nematodes exposed to KARATE 2.5 WG, LAMBDA SUPER 2.5EC or neem oil ranges between 95% and 98%. In the treated plots, Steinernema sp. 83a was the most virulent with the highest P. xylostella mortality (87% at 50 IJs·cm-2 after 24 h) while only 35% larval mortality was recorded for H. sonorensis applied at the same dose. Population density of nematodes which penetrated DBM larvae reached 9 ± 3I IJs·larva-1 for H. sonorensis KF723827 and 6 ± 2 IJs·larva-1 for Steinernema sp. 83a. In cadaver of DBM, nematode reproduction did not appear to be affected by the contact with insecticides. Conclusions. Based on our research, we conclude that the three insecticides did not affect EPNs efficiency and could be used in combination against DBM.


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