Efficacy Of Entomopathogenic Nematodes Research Articles

Management of Bemisia tabaci on vegetable crops using entomopathogens

The sweetpotato whitefly, Bemisia tabaci Gennadius, is a devastating insect pest on vegetable crops around the world. This pest causes significant damage by directly feeding on vegetables, excreting honeydew, inducing plant physiological disorders, and transmitting plant viruses. The combined direct and indirect damage to vegetable crops has led to substantial economic losses. The heavy reliance on chemical insecticides for whitefly control has led to considerable resistance to many insecticides in whitefly populations. Therefore, integrated pest management (IPM) that includes entomopathogens is considered as a sustainable and effective approach against B. tabaci. This review focuses on biological control of B. tabaci using entomopathogens, including entomopathogenic fungi (EPF), entomopathogenic nematodes (EPN), and entomopathogenic bacteria (EPB). Among them, EPF is the mostly explored group of entomopathogens for B. tabaci control. In particular, Beauveria bassiana (Balsamo-Crivelli) Vuillemin, Akanthomyces lecanii (Zimm.) Spatafora, Kepler and B. Shrestha, Cordyceps javanica (Frieder. & Bally) Kepler, B. Shrestha & Spatafora, and C. fumosorosea (Wize) Kepler, B. Shrestha & Spatafora are the most commonly used EPF species for whitefly control. The control efficacy of EPN against B. tabaci varies with strains/species and concentrations of the EPN, whitefly nymphal instars, host plants, and environmental conditions. Most research on evaluating the virulence of various EPB isolates against whiteflies has been conducted in the laboratory. Entomopathogens offer a promising strategy for whitefly management in vegetables. This review discusses research updates on the three entomopathogen groups for whitefly control, barriers in broad adoption by vegetable growers, and future directions.

The Efficacy of Entomopathogenic Nematodes Plus an Adjuvant against Helicoverpa zea and Chrysodeixis includens in Aboveground Applications.

In the southern United States, corn earworm, Helicoverpa zea (Boddie), and soybean looper, Chrysodeixis includens (Walker) are economically important crop pests. Although Bt crops initially provided effective control of target pests such as H. zea, many insect pests have developed resistance to these Bt crops. Alternative approaches are needed, including biological control agents such as entomopathogenic nematodes (EPNs). However, the effectiveness of EPNs for aboveground applications can be limited due to issues such as desiccation and ultraviolet radiation. Effective adjuvants are needed to overcome these problems. Ten strains of EPNs were tested for virulence against eggs, first to fourth instars, fifth instars, and pupae of H. zea and C. includens in the laboratory. These 10 EPN strains were Heterorhabditis bacteriophora (HP88 and VS strains), H. floridensis (K22 strain), Hgkesha (Kesha strain), Steinernema carpocapsae (All and Cxrd strains), S. feltiae (SN strain), S. rarum (17c+e strain), and S. riobrave (355 and 7-12 strains). EPNs could infect eggs of H. zea or C. includens in the laboratory, but the infection was low. The mortality caused by 10 EPN strains in seven days was significantly higher for the first to fourth instars of H. zea compared to the control, as was the fifth instars of H. zea. Similarly, for the first to fourth and fifth instars of C. includens, the mortality was significantly higher compared to the controls, respectively. However, only S. riobrave (355) had significantly higher mortality than the control for the pupae of H. zea. For the pupae of C. includens, except for H. bacteriophora (HP88), S. rarum (17c+e), and H. floridensis (K22), the mortality of the other seven strains was significantly higher than the control. Subsequently, S. carpocapsae (All) and S. riobrave (7-12) were chosen for efficacy testing in the field with an adjuvant 0.066% Southern Ag Surfactant (SAg Surfactant). In field experiments, the SAg Surfactant treatment significantly increased the mortality and EPN infection for S. carpocapsae (All) on first instars of H. zea in corn plant whorls. On soybean plants, with the SAg Surfactant, S. carpocapsae (All) was more effective than S. riobrave (7-12) on fifth instars of C. includens. This study indicates that EPNs can control H. zea and C. includens, and SAg Surfactant can enhance EPN efficacy.

Attraction of entomopathogenic nematodes to black truffle and its volatile organic compounds: A new approach for truffle beetle biocontrol

The European truffle beetle, Leiodes cinnamomeus, is the most important pest in black truffle (Tuber melanosporum) plantations. Entomopathogenic nematodes (EPNs) are a promising biological control agents against L. cinnamomeus. EPNs may employ multiple sensory cues while seeking for hosts, such as volatile organic compounds (VOCs) and CO2 gradients. We report for the first time the attraction of EPNs to truffle fruitbodies, and identified some VOCs potentially playing a key role in this interaction. We conducted olfactometer assays to investigate the attraction behavior of Steinernema feltiae and Steinernema carpocapsae towards both T. melanosporum fruitbodies and larvae of L. cinnamomeus. Subsequently, a chemotaxis assay using agar plates was performed to determine which of the 14 of the main VOCs emitted by the fruitbodies attracted S. feltiae at low (0.1 %) and high (mg/100 g truffle) concentrations. Both EPN species were attracted to mature fruitbodies of T. melanosporum, which may enhance the likelihood of encountering L. cinnamomeus during field applications. L. cinnamomeus larvae in the presence of truffles did not significantly affect the behavior of EPNs 24 h after application, underscoring the importance of the chemical compounds emitted by truffles themselves. Chemotaxis assays showed that four long-chain alcohol compounds emitted by T. melanosporum fruitbodies attracted S. feltiae, especially at low concentration, providing a first hint in the chemical ecology of a little-studied ecological system of great economical value. Further studies should be conducted to gain a finer understanding of the tritrophic interactions between T. melanosporum, EPNs, and L. cinnamomeus, as this knowledge may have practical implications for the efficacy of EPNs in the biological control of this pest.

Thiourea as a polyphenol oxidase inhibitor enhances host infection by the entomopathogenic nematode, Heterorhabditis beicherriana

Entomopathogenic nematodes (EPN) are potent microbial biocontrol agents applied commercially against various economically important insect pests. The efficacy of EPN in the field may be partially reduced when compared to chemical insecticides due to its sensitivity to environmental stressors like temperature, desiccation, and UV light. Thus, researchers have developed methods to enhance the effectiveness of EPN, such as screening or breeding stress-resistant strains and creating adjuvants for EPN protection in the field. This study used another strategy to lower the host’s immunity so that the anti-infection ability of the pest wanes, and the virulence of EPN waxes accordingly. In addition to its use as a plant growth regulator, thiourea also functions as an inhibitor of polyphenol oxidase (PO) in insects. Thiourea can inhibit a key interaction in the humoral immunity of insects, so we utilized it to enhance the efficacy of EPN. To investigate the effects of thiourea on PO activity inhibition and EPN pathogenesis, we studied the effects of thiourea on survival, infectivity, reproduction, and host searching ability of the EPN, Heterorhabditis beicherriana, and monitored in vivo and in vitro polyphenol oxidase activity of the model insect host, Galleria mellonella. The survival of H. beicherriana infective juveniles (IJs) was barely affected after exposure to 0.5 mM and 1 mM thiourea solution, and the reproductive output of H. beicherriana IJs (after applying 50, 100 and 200 IJs per host) in 0.5 mM and 1 mM thiourea was not different compared to the control. However, the LD50 of G. mellonella larvae caused by H. beicherriana without thiourea was significantly higher than H. beicherriana IJs in thiourea. Moreover, thiourea inhibited in vivo and in vitro polyphenol oxidase activity of G. mellonella infected by EPNs at different concentrations. Thus, thiourea can improve the biological control efficacy of EPNs, and the enhanced environmentally friendly approach may apply to diverse cropping systems.

Bazı entomopatojen nematodların etkinliğinde kuraklığın rolü

Entomopathogenic nematodes (EPNs) are endoparasitic organisms commonly used in the control of agricultural pests. There are several factors that determine the efficacy of EPNs on hosts, with one of the most significant being soil moisture. The aim of this study is to determine the effectiveness of some EPNs on hosts at different doses and under different soil moisture conditions. The study utilized 1 Hybrid Strain and 3 EPN isolates, Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae) HBH hybrid strain, Steinernema carpocapsae Weiser, 1955 TUR-S4 isolate, and Steinernema feltiae Weiser, 1955 (Rhabditida: Steinernematidae) TUR-S3 and S-Bilecik isolates. These species were applied to Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) larvae at 5, 10, and 15 Infective Juveniles (IJs) doses, under 1, 4, 7, 10, and 13% soil moisture conditions. The study was conducted in 2024 at Bursa Uludağ University, Faculty of Agriculture, Department of Plant Protection, Nematology Laboratory. As a result, the highest mortality rates on T. molitor larvae were obtained at 13% soil moisture with 15 IJs, 100% for HBH, 93.33% for TUR-S4, 86.67% for TUR-S3, and 83.33% for S-Bilecik. This study carries important implications for understanding the relationship between EPN efficacy on hosts and soil moisture.

Influence of Abiotic Factors on Efficacy of Entomopathogenic Nematodes

Entomopathogenic nematodes (EPNs) are potential biocontrol agents against many insect pests. The infective juveniles (IJs) dwell in soil ecosystem in a free-living state which is responsible for pest suppression under certain environmental condition. These IJs are faced with a wide range of environmental conditions during this stage. Abiotic factors such as temperature, moisture/relative humidity, soil texture and structure, ultraviolet radiation influence the survival, growth and development, and reproduction of entomopathogenic nematodes and ultimately their performance on bioefficacy against insect pests.

Soil moisture conditions alter behavior of entomopathogenic nematodes.

A variety of environmental factors can disrupt biotic interactions between plants, insects and soil microorganisms with consequences for agricultural management and production. Many of these belowground interactions are mediated by volatile organic compounds (VOCs) which can be used for communication under appropriate environmental conditions. Behavioral responses to these compounds may likewise be dependent on varying soil conditions which are influenced by a changing climate. To determine how changing environmental conditions may affect VOC-mediated biotic interactions, we used a belowground system where entomopathogenic nematodes (EPNs) - tiny roundworm parasitoids of soil-borne insects - respond to VOCs by moving through the soil pore matrix. Specifically, we used two genera of EPNs - Heterorhabditis and Steinernema - that are known to respond to four specific terpenes - α-pinene, linalool, d-limonene and pregeijerene - released by the roots of plants in the presence of herbivores. We assessed the response of these nematodes to these terpenes under three moisture regimes to determine whether drier conditions or inundated conditions may influence the response behavior of these nematodes. Our results illustrate that the recovery rate of EPNs is positively associated with soil moisture concentration. As soil moisture concentration increases from 6% to 18%, substantially more nematodes are recovered from bioassays. In addition, we find that soil moisture influences EPN preference for VOCs, as illustrated in the variable response rates. Certain compounds shifted from acting as a repellent to acting as an attractant and vice versa depending on the soil moisture concentration. On a broad scale, we demonstrate that soil moisture has a significant effect on EPN host-seeking behavior. EPN efficacy as biological control agents could be affected by climate change projections that predict varying soil moisture concentrations. We recommend that maintaining nematodes as biological control agents is essential for sustainable agriculture development, as they significantly contribute not only to soil health but also to efficient pest management. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

ENTOMOPATHOGENIC NEMATODES AS BICONTROL AGENTS

Entomopathogenic nematodes (EPN) are used for management of insect pest. Parasitic relationship is based on symbiotic acting of the nematodes from genera Steinernema and Heterorhabditis and bacteria Xenorhabdus and Photorhabdus. They occur naturally in soil environment, but their natural populations mostly are not able to control pests at the level required by farmers. Mass production in liquid fer mentors can provide production for large scale application at competitive price compared to synthetic insecticides. Application is done by common application equipment for pesticides considering some specificity of bicontrol agents and by irrigation equipment. The major challenge for EPN efficacy is moisture. Provided enough moisture during searching and parasiting hosts can provide successful control Adjusting application to specificity of the EPN and the host is often necesary. They are he most efficent against soil stages of the insects. They found place in come rial application in fruit and vegetable production, ornamental, mushrooms. They are among the safest biological control agents what makes the desirable biocontrol agents. EPN's are often exempted from registration when it is scientificaly confirmed presence of natural populations within the country.

From soil to host: Discovering the tripartite interactions between entomopathogenic nematodes, symbiotic bacteria and insect pests and related challenges

Entomopathogenic nematodes (EPNs) are emerging as key agents in ecological networks, exhibiting a wide range of interactions with other biotic components, in particular their symbiotic relationships with the bacteria Xenorhabdus and Photorhabdus. This comprehensive study reveals their global distribution and local benefits and highlights their historical background and taxonomic grouping. The importance of the secreted compounds of EPNs in pest management is highlighted by an in-depth exploration of their potential as biocontrol agents. The complex interactions between nematodes and endosymbiotic bacteria are dissected to understand their mutualistic relationships and subsequent effects on host organisms. The strategies used by EPNs to locate, recognize, and invade hosts will be carefully analyzed to understand their pathogenic phase and the resulting immune responses elicited in insect hosts. Infection strategies employed by the EPN-bacteria complex will be examined to assess their efficacy and real-world challenges. The challenges associated with the effective use of EPNs, including environmental constraints and the need for improved efficacy, will be thoroughly investigated to propose viable solutions. This study paves the way for harnessing the biocontrol potential of EPNs and provides a robust framework for future research to improve the efficacy of EPNs in sustainable agriculture and pest management while addressing the challenges identified.

Efficacy of Entomopathogenic nematodes on some Lepidopteran larvae

Efficacy of Entomopathogenic nematodes on some Lepidopteran larvae

Bazı pestisitlerin entomopatojen nematodların (Rhabditida: Heterorhabditidae ve Steinernematidae) yönelimleri üzerine etkisi

Entomopathogenic nematodes (EPNs) play a crucial role in biological control, but they can be also applied together with pesticides. Therefore, the compatibility of pesticides with EPNs and the influence on their behavior significantly affect field success. This study investigated how selected pesticides (Deltamethrin, Imidacloprid, Pendimethalin, 2,4-D, and Boscalid + Pyraclostrobin) affect the orientation behavior of three commercial EPN species. Trials were conducted using steel olfactometers followed by the assessment of EPN dispersal ratios after 24 hours. The study was conducted in the Laboratory of the Plant Protection Department, Faculty of Agriculture and Natural Sciences, Bilecik Şeyh Edebali University between 2022 and 2023. According to the results, while nearly all pesticides exhibited a significant impact on the dispersal behavior of EPNs, the most notable effects were observed in the trials involving 2,4-D and Imidacloprid. These two pesticides demonstrated both repellent and attractive effects on different EPN species. The impact of other pesticides was comparatively negligible. All EPN species exhibited higher orientation towards larvae than the control application. The orientation behavior displayed variations depending on the pesticide type and the EPN species involved. It is expected that this study will contribute to our understanding of the relationship between EPNs and pesticides, and ultimately enhancing the efficacy of EPNs.

Potential of Entomopathogenic Nematodes to Control the Cabbage Stem Flea Beetle Psylliodes chrysocephala.

Cabbage stem flea beetle (CSFB) is an important pest of oilseed rape that was controlled by neonicotinoid seed treatments until they were banned for this use in 2013. Since then, CSFB has been a difficult pest to control, partly due to widespread resistance to pyrethroid insecticides. Alternate solutions are necessary. Here, four entomopathogenic nematode (EPN) species were tested against CSFB adults under laboratory conditions. In addition, a bioassay was completed to test for EPN compatibility with a range of adjuvants (glycerin, xanthan gum and flame retardant) to protect EPNs from UV radiation and desiccation. Results show that EPNs have the potential to control CSFB adults under laboratory conditions. Heterorhabditis bacteriophora caused 75% CSFB mortality at a concentration of 4000 nematodes/mL after six days, Steinernema feltiae caused 80% CSFB mortality when applied at a concentration of 40,000 nematodes/mL after two days, Steinernema carpocapsae caused 85% mortality at a concentration of 10,000 nematodes/mL after six days, and Steinernema kraussei caused no more than 70% CSFB mortality overall compared to the water control, which led to 23% mortality. Steinernema feltiae and H. bacteriophora survival was 100% when exposed to adjuvants, except S. feltiae with glycerin and H. bacteriophora with flame retardant. Further research to evaluate the efficacy of EPN and adjuvants under field conditions is necessary.

Increasing the survival and efficacy of entomopathogenic nematodes on exposed surfaces by Pickering emulsion formulations offers new venue for foliar pest management

Formulation technology has been the primordial focus to improve the low viability and erratic infectivity of entomopathogenic nematodes (EPNs) for foliar application. Adaptability to the fluctuating environment is a key trait in ensuring the survival and efficacy of EPNs. Hence, tailoring formulations towards EPNs foliar applications would effectively deliver consistent and reliable results for above-ground applications. EPNs survival and activity were characterized in novel Pickering emulsion post-application in planta cotton foliage. Two different types of novel formulations, Titanium Pickering emulsion (TPE) and Silica Pickering emulsion Gel (SPEG), were tailored for EPNs foliar applications. We report an extension of survival and infectivity to 96 hrs under controlled conditions by SPEG formulations for survival of IJ's on cotton foliage. In addition, survival of IJs (LT50) was extended from 14hrs in water to > 80 hrs and > 40 hrs by SPEG and TPE respectively. SPEG accounted for the slowest decrease of live IJs per surface area in comparison to TPE and control samples over time, exhibiting a 6-fold increase at 48 hrs. Under extreme conditions, survival and efficacy were extended for 8hrs in SPEG compared to merely 2hrs in control. Potential implications and possible mechanisms of protection are discussed.

Nematicidal Effects of Four Terpenes Differ among Entomopathogenic Nematode Species

Entomopathogenic nematodes (EPNs) have been studied for more than half a century, and employed for insect pest management using augmentation, conservation, and classical biological control approaches. As obligate lethal parasitoids of insect larvae, EPN navigate a chemically complex soil environment and interact with their insect hosts, plants, and each other. EPN responses to various terpenes, such as herbivore-induced plant volatiles, have the potential to enhance EPN efficacy through their attraction. However, several of the terpenes are currently being formulated as biological fungicides, insecticides, and acaricides for above- or below-ground applications. We conducted laboratory experiments to investigate the possible nematicidal effect of four terpenes, carvacrol, geraniol, eugenol, and thymol, to two heterorhabditids and two steinernematid species. Each terpene showed nematicidal activity against at least two of the four EPN species, with carvacrol showing the strongest activity and Heterorhabditis bacteriophora the highest sensitivity. Despite the high sensitivity of both heterorhabditids and near-zero sensitivity of the steinernematids to thymol, carvacrol, and eugenol, an increasing effect was observed when steinermatid nematodes were exposed to geraniol, and a decreasing effect for heterorhabditids, with H. bacteriophora exhibiting higher mortality than H. indica. The virulence of the nematodes towards fourth instar Galleria mellonella was also tested after exposure to the median lethal doses of each terpene. No significant difference in virulence was observed between nematodes that were exposed or not exposed to sublethal doses. The experiments suggest that the tested terpenes have a strong effect on EPN viability, which should be considered when combining the two approaches in IPM. The terpenes did not have a universal effect on all nematode species, which merits further investigation, while virulence tests suggest that sublethal doses of these terpenes have no effect on the host-killing performance of EPNs.

Efficacy of entomopathogenic nematodes against Diaphania indica (Saunders) (Lepidoptera: Crambidae) in bittergourd

Efficacy of entomopathogenic nematodes against Diaphania indica (Saunders) (Lepidoptera: Crambidae) in bittergourd

Biocontrol potential of endosymbiotic bacteria of entomopathogenic nematodes against the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

BackgroundThe tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a major pest of tomato plants threatening global tomato production. The control of the pest is becoming increasingly difficult due to the rapid development of resistance to insecticides. Entomopathogenic nematodes (EPNs) of families Steinernematidae and Heterorhabditidae are successful biocontrol agents for many insect pests. Recently, their bacteria, Xenorhabdus spp. and Photorhabdus spp. have attracted great attention due to their major role in the pathogenicity of EPNs. In the present study, the pathogenicity of eleven EPNs isolates belonging to Steinernema feltiae and Heterorhabditis bacteriophora species was screened against the 1st/2nd and 3rd/4th instar larvae of T. absoluta. The cell-free supernatants and cell suspensions of the symbiotic bacteria from the most efficient isolates were further evaluated for their biocontrol potential in the oral and contact treatments on the larvae of T. absoluta.ResultsKBC-4 and MCB-8 isolates of S. feltiae showed superior virulence relative to other EPNs species/isolates and induced 90% larval mortality against the 3rd/4th instar of T. absoluta larvae, whereas there were no clear differences in the efficacy of EPNs species/isolates against the 1st/2nd instar of T. absoluta. The 1st/2nd instar of T. absoluta larvae was more susceptible to cell-free supernatants and cell suspension of selected EPNs. The highest mortality (80%) was obtained from X. bovienii MCB-8 strain in the contact treatment of supernatants. In contact treatment of cell suspension, higher mortalities were obtained compared to oral treatments. Mortality rates ranged between 30 and 57.5% in the contact treatments of cell suspensions while the highest mortality did not exceed 20% in oral treatments. The antifeedant activity was observed in oral treatments of cell suspension and most of the larvae avoided feeding on treated leaves.ConclusionThe results indicated that symbiotic bacteria of EPNs had a great potential against T. absoluta larvae and contact treatment of cell-free supernatants against early instars of T. absoluta can be an ideal application. However, further studies are needed to investigate the field effectiveness of symbiotic bacteria.

Tolerance of Steinernema carpocapsae infective juveniles in novel nanoparticle formulations to ultraviolet radiation

Entomopathogenic nematodes (EPNs) are susceptible to abiotic environmental factors including ultraviolet (UV) radiation, which affects the survival and efficacy. This study evaluated nanoparticle (NP) formulations for protecting Steinernema carpocapsae infective juveniles (IJs) from UV radiation. First, silica-NH2 NPs at oil-to-water ratios of 2:8, 3:7 and 4:6 were compared with Barricade Fire Gel (1 % and 2 %) and a water control (aqueous IJs) by exposing IJs to UV light (254 nm) for 0, 10 and 20 min. Barricade gel (especially 2 % Barricade) significantly improved IJs viability after UV treatment, while all three NPs had adverse effects on IJ viability after UV radiation. Subsequently, two silica (SiO2 basic and advanced) and one titania (TiO2) based formulations were tested with Barricade (1 % and 2 %) and a water control. The titania-NH2 NPs provided the highest UV protection, and IJ viability and virulence were not reduced even after 20-min UV. Except TiO2, only 2 % Barricade at 10-min UV and SiO2 basic at 20-min UV had lower IJ mortality than the water control. Only TiO2 formulated IJs caused higher insect mortality and infection levels than aqueous IJs after UV treatment. The UV tolerance of TiO2 was further examined by assessing the number of nematodes invading the hosts. Consistent with virulence tests, the number of invading nematodes in titania-NH2 NPs did not decrease after UV radiation for 10 or 20 min compared with the no-UV control. The anti-UV capability of titania-NH2 NPs has promise as a tool to enhance biocontrol efficacy of EPNs under field conditions.

Survival and efficacy of entomopathogenic nematodes on exposed surfaces

Entomopathogenic nematodes (EPN) species differ in their capability to withstand rapid desiccation (RD). Infective juveniles of Steinernema carpocapsae are a better adaptable and tolerant than Steinernema feltiae or Heterorhabditis bacteriophora as, an optimal RH of > 90% is required by S. feltiae and H. bacteriophora while maintaining RH equivalent to 74% could sustain survival of S. carpocapsae under RD. Our findings from infectivity suggest that following application, shrunk IJs are acquired passively by the larvae, probably rehydrate and resume infection within the insect gut. Water loss rate is a key factor affecting survival of S. carpocapsae on exposed surfaces. The present study provides the foundation for characterizing mechanism of rapid rate of water loss in EPN. ATR-FTIR is a rapid and reliable method for analysis of water loss. Changes in peak intensity was observed at 3100–3600 cm−1 (OH bonds of water), 2854 cm−1 (CH stretching of symmetric CH2, acyl chains), 2924 cm−1 (CH stretching of anti-symmetric CH2, lipid packing heterogeneity), 1634 cm−1 (amide I bonds) indicate major regions for hydration dependent changes in all EPN species. FTIR data also indicates that, S. carpocapsae contains strong water interacting regions in their biochemical profile, which could be an influencing factor in their water holding capacity under RD. ATR-FTIR were correlated to water content determined gravimetrically by using Partial Least square –Regression and FTIR multivariate method, which could be used to screen a formulation’s potential to maintain or delay the rate of water loss in a rapid and efficient manner.

Efficacy of entomopathogenic nematode, Heterorhabditis indica against diamondback moth, Plutella xylostella (L.) under laboratory conditions

Efficacy of entomopathogenic nematode, Heterorhabditis indica against diamondback moth, Plutella xylostella (L.) under laboratory conditions

Isolation and biocontrol efficacy of entomopathogenic nematodes Steinernema carpocapsae, Steinernema monticolum and Rhabditis blumi on lepidopteran pest Spodoptera litura

Entomopathogenic nematodes (EPN) are an important component of biological control of agricultural pests. Depending on the ambient temperature, EPNs efficacy may be affected by high temperature between 30 and 40°C is usually featured in tropical and subtropical regions. In the present study, we isolated three EPN strains, namely GNAF1, NBS1 and MAF2, exhibiting high virulence on Spodoptera litura larvae and tested their lepidopteran larval control efficacy at temperatures ranging from 20 °C to 40 °C. Results show that larval control efficacy of the isolated nematodes was not affected at higher temperatures, higher emergence of infective juveniles was observed at higher temperatures, showing that EPN multiplication is not affected at higher temperatures. Based on 18s rDNA sequence these strains were identified as Steinernema carpocapsae -MK350941; Steinernema monticolum -MK503674; Rhabditis blumi -MN453373. The present study shows that these EPN can be used for controlling lepidopteran insect pest in tropical and subtropical agroecosystems.