scholarly journals Insecticidal Effect of Entomopathogenic Nematodes and the Cell-Free Supernatant from Their Symbiotic Bacteria against Philaenus spumarius (Hemiptera: Aphrophoridae) Nymphs

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 448
Author(s):  
Ignacio Vicente-Díez ◽  
Rubén Blanco-Pérez ◽  
María del Mar González-Trujillo ◽  
Alicia Pou ◽  
Raquel Campos-Herrera
Keyword(s):  
Entomopathogenic Nematodes ◽  
Management Practices ◽  
Integrated Management ◽  
Bacterial Pathogen ◽  
Steinernema Feltiae ◽  
Symbiotic Bacteria ◽  
Successful Implementation ◽  
Philaenus Spumarius ◽  
Cell Free Supernatant ◽  
Insecticidal Effect

The meadow spittlebug Philaenus spumarius (Hemiptera: Aphrophoridae) is the primary vector of Xylella fastidiosa (Proteobacteria: Xanthomonadaceae) in Europe, a pest–disease complex of economically relevant crops such as olives, almonds, and grapevine, managed mainly through the use of broad-spectrum pesticides. Providing environmentally sound alternatives to reduce the reliance on chemical control is a primary challenge in the control of P. spumarius and, hence, in the protection of crops against the expansion of its associated bacterial pathogen. Entomopathogenic nematodes (EPNs) are well-known biocontrol agents of soil-dwelling arthropods. Recent technological advances in field applications, including improvements in obtaining cell-free supernatant from their symbiotic bacteria, allow their successful implementation against aerial pests. Thus, this study aimed to evaluate, for the first time, the efficacy of EPN applications against nymphal instars of P. spumarius. We tested four EPN species and the cell-free supernatant of their corresponding symbiotic bacteria: Steinernema feltiae–Xenorhabdus bovienii, S. carpocapsae–X. nematophila, S. riojaense–X. kozodoii, and Heterorhabditis bacteriophora–Photorhabdus laumondii subsp. laumondii. First, we showed that 24 and 72 h exposure to the foam produced by P. spumarius nymphs did not affect S. feltiae virulence. The direct application of steinernematid EPNs provided promising results, reaching 90, 78, and 53% nymphal mortality rates after five days of exposure for S. carpocapsae, S. feltiae, and S. riojaense, respectively. Conversely, the application of the cell-free supernatant from P. laumondii resulted in nymphal mortalities of 64%, significantly higher than observed for Xenorhabdus species after five days of exposure. Overall, we demonstrated the great potential of the application of specific EPNs and cell-free supernatant of their symbiont bacteria against P. spumarius nymphs, introducing new opportunities to develop them as biopesticides for integrated management practices or organic vineyard production.

Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes

Nematology ◽  
1999 ◽  
Vol 1 (7) ◽  
pp. 735-743 ◽  
Author(s):  
Parwinder S. Grewal ◽  
Edwin E. Lewis ◽  
Sudha Venkatachari
Keyword(s):  
Meloidogyne Incognita ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Feltiae ◽  
Symbiotic Bacteria ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Tomato Roots ◽  
Xenorhabdus Nematophilus ◽  
Plant Parasitic

Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.

scholarly journals Nematobacterial Complexes and Insect Hosts: Different Weapons for the Same War

Insects ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 117 ◽  
Author(s):  
Maurizio Brivio ◽  
Maristella Mastore
Keyword(s):  
Entomopathogenic Nematodes ◽  
Insect Pests ◽  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Symbiotic Bacteria ◽  
Published Data ◽  
Immune Recognition ◽  
Insect Host ◽  
Biological Control Agents ◽  
Immune Pathways

Entomopathogenic nematodes (EPNs) are widely used as biological control agents against insect pests, the efficacy of these organisms strongly depends on the balance between the parasitic strategies and the immune response of the host. This review summarizes roles and relationships between insect hosts and two well-known EPN species, Steinernema feltiae and Steinernema carpocapsae and outlines the main mechanisms of immune recognition and defense of insects. Analyzing information and findings about these EPNs, it is clear that these two species use shared immunosuppression strategies, mainly mediated by their symbiotic bacteria, but there are differences in both the mechanism of evasion and interference of the two nematodes with the insect host immune pathways. Based on published data, S. feltiae takes advantage of the cross reaction between its body surface and some host functional proteins, to inhibit defensive processes; otherwise, secretion/excretion products from S. carpocapsae seem to be the main nematode components responsible for the host immunosuppression.

scholarly journals Characterization of entomopathogenic nematodes and symbiotic bacteria active against Spodoptera frugiperda (Lepidoptera: Noctuidae) and contribution of bacterial urease to the insecticidal effect

2012 ◽  
Vol 63 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Juliana De Marco Salvadori ◽  
Marina Schumacher Defferrari ◽  
Rodrigo Ligabue-Braun ◽  
Elene Yamazaki Lau ◽  
José Roberto Salvadori ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Entomopathogenic Nematodes ◽  
Symbiotic Bacteria ◽  
Insecticidal Effect ◽  
Lepidoptera Noctuidae

scholarly journals Integrated Management of Chive Gnats (Bradysia odoriphaga Yang & Zhang) in Chives Using Entomopathogenic Nematodes and Low-Toxicity Insecticides

Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 161 ◽  
Author(s):  
Xun Yan ◽  
GuoYu Zhao ◽  
RiChou Han
Keyword(s):  
Entomopathogenic Nematodes ◽  
Integrated Management ◽  
Cost Effective ◽  
Practical Method ◽  
Environmental Safety ◽  
Steinernema Feltiae ◽  
Toxic Chemical ◽  
Synergistic Interactions ◽  
Major Pest ◽  
Low Toxicity

Bradysia odoriphaga is a major pest that causes damage to chive production, and which has developed resistance to highly toxic chemical insecticides. Entomopathogenic nematodes (EPN) show a high potential for B. odoriphaga control. This study aimed to develop an effective management method against B. odoriphaga larvae, using EPN with low-toxicity insecticides. Fourteen selected insecticides had no significant effects on the survival and infectivity of Steinernema feltiae SN and Heterorhabditis indica LN2. Synergistic interactions were observed for imidacloprid and osthole with S. feltiae SN against B. odoriphaga larvae. Steinernema feltiae SN was more effective than H. indica LN2 against B. odoriphaga at 15 and 20 °C, and the addition of imidacloprid at 1/10 recommended concentration (RC) significantly increased the efficacy of S. feltiae SN. The year-round occurrence of the B. odoriphaga larvae in chive fields treated by EPN and imidacloprid at 1/10 RC was studied. Results showed that the application of EPN with imidacloprid at 1/10 RC successfully suppressed larval populations of B. odoriphaga in chive fields, thus significantly increasing the yield of chive. The practical method of applying EPN–imidacloprid combinations provided a cost-effective and environmental safety strategy for controlling B. odoriphaga larvae in chive production, which can reduce the usage of toxic chemical insecticides.

Effectiveness of Entomopathogenic Nematodes Against Ceratitis capitata (Diptera: Tephritidae) Pupae and Nematode Compatibility with Chemical Insecticides

2021 ◽  
Author(s):  
Maguintontz Cedney Jean-Baptiste ◽  
Andressa Lima de Brida ◽  
Daniel Bernardi ◽  
Sérgio da Costa Dias ◽  
Juliano de Bastos Pazini ◽  
...  
Keyword(s):  
Biological Control ◽  
Entomopathogenic Nematodes ◽  
Ceratitis Capitata ◽  
Integrated Management ◽  
Fruit Fly ◽  
Steinernema Carpocapsae ◽  
Mediterranean Fruit Fly ◽  
Fruit Crops ◽  
Class 1 ◽  
Pupal Mortality

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.

scholarly journals Organic Farming and Cover-Crop Management Reduce Pest Predation in Austrian Vineyards

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 220
Author(s):  
Jo Marie Reiff ◽  
Sebastian Kolb ◽  
Martin H. Entling ◽  
Thomas Herndl ◽  
Stefan Möth ◽  
...  
Keyword(s):  
Organic Farming ◽  
Pest Control ◽  
Cover Crops ◽  
Cover Crop ◽  
Management Practices ◽  
Integrated Management ◽  
Lobesia Botrana ◽  
Management Options ◽  
Natural Pest Control ◽  
Predation Rates

Habitat simplification and intensive use of pesticides are main drivers of global arthropod declines and are, thus, decreasing natural pest control. Organic farming, complex landscapes, and local vineyard management practices such as implementation of flower-rich cover-crop mixtures may be a promising approach to enhance predator abundance and, therefore, natural pest control. We examined the effect of organic versus integrated management, cover-crop diversity in the vineyard inter-rows, and landscape composition on the natural pest control of Lobesia botrana eggs and pupae. Predation of L. botrana pupae was reduced by organic farming and species-poor cover-crops by about 10%. Predation rates of L. botrana eggs did not differ significantly in any of the studied management options. Dominant predators were earwigs (Forficulidae), bush crickets (Tettigoniidae), and ants (Formicidae). Negative effects of organic viticulture are most likely related to the negative nontarget effects on arthropods related to the frequent sulfur and copper applications in combination with the avoidance of strongly damaging insecticides by integrated winegrowers. While a 10% difference in predation rates on a single pest stage is unlikely to have strong practical implications, our results show that the assumed effectiveness of environmentally friendly agriculture needs to be evaluated for specific crops and regions.

scholarly journals Integrated Management of Downy Mildew on Slicing Cucumber With Fungicides and Host Resistance But Not Trellising

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2592-2598
Author(s):  
Anthony P. Keinath
Keyword(s):  
Downy Mildew ◽  
Host Resistance ◽  
Management Practices ◽  
Integrated Management ◽  
Cultivar Resistance ◽  
Fall Season ◽  
Fungicide Treatment ◽  
Progress Curve ◽  
Management Techniques ◽  
The Mean

The objective of this study was to evaluate fungicide applications, host resistance, and trellising, alone and in combination, as management practices for downy mildew on slicing cucumber. A split-split plot experimental design was used with three and four replications in spring and fall 2017, respectively. The whole-plot treatment was fungicide, four applications of chlorothalonil (Bravo Weather Stik 6SC) alternated with three applications of cyazofamid (Ranman 400SC), or water. Split plots were nontrellised or trellised with four strings supported by stakes. Split-split plots were cultivar Bristol, which is intermediately resistant to downy mildew, or cultivar Speedway, which is susceptible to downy mildew with similar parentage as Bristol. In both seasons, area under the disease progress curve (AUDPC) values were lower with fungicides than water for both cultivars. In the spring, AUDPC for Bristol was lower than for Speedway regardless of fungicide treatment. In the fall, Bristol had a lower AUDPC than Speedway with fungicides, but the AUDPC did not differ between the two cultivars with water. The mean AUDPC for trellised plants (376.2) was lower than for nontrellised plants (434.0; P = 0.007). Fungicide applications increased marketable and total fruit weights in both seasons (P ≤ 0.0002). Marketable weight with fungicides was almost double (93% greater) the marketable weight with water. Marketable weight was 55% greater for Bristol than for Speedway in spring, but yields did not differ between cultivars in fall (season-by-cultivar interaction, P ≤ 0.0003). Because trellising had no effect on marketable yields (P = 0.11), trellising is not recommended for managing downy mildew on slicing cucumber. Of the three management techniques examined, fungicides had the largest effects on disease and yields, followed by cultivar resistance.

scholarly journals Internal barriers to supply chain management implementation in a South African traditional university

2018 ◽  
Vol 12 ◽  
Author(s):  
Mamokgadi Z. Masete ◽  
Chengedzai Mafini
Keyword(s):  
Higher Education ◽  
Supply Chain ◽  
Supply Chain Management ◽  
South African ◽  
Management Practices ◽  
Higher Education Institutions ◽  
Successful Implementation ◽  
Public Higher Education ◽  
Chain Management ◽  
Internal Barriers

Background: The demand for higher education in South Africa continues to increase, placing pressure on public higher education institutions to satisfy this demand. Supply chain management is one of the practices that may be implemented to ensure that public universities improve their operations and can, therefore, meet the increased demand for higher education in the country.Objectives: This study aimed to explore the barriers to the implementation of supply chain management practices at a South African public university.Method: The study used a qualitative case study approach using a sample of 17 members of management and staff at a South African traditional university in the Limpopo Province. Data were collected using a combination of a focus group discussion and semi-structured in-depth interviews.Results: The study generated eight themes that embody the barriers to the implementation of supply chain management at the institution. These themes were labelled as stakeholder buy-in, knowledge of supply chain management, supply chain systems and processes, procurement policy and practices, implementation of supply chain management, stakeholder change management, human resource management and organisational culture.Conclusion: Various internal barriers impair the implementation of supply chain management practices at the institution. Administration at the institution has invested limited resources, time and initiatives to ensure the successful implementation of supply chain management. The focus should be directed to finding lasting solutions to each of the barriers identified in this study. Further studies should address the issue of external barriers to supply chain management in public higher education institutions.

Sign in / Sign up

Export Citation Format

Share Document