Egg Hatching Inhibition Research Articles

Acaricidal Efficacy of Cassia sieberiana DC (Caesalpinaceae) Stem Bark Aqueous Extract on Hyalomma KOCH, 1844 (Acari: Ixodidae) Reproductive Stages

One of the most significant challenges facing tick control through chemical acaricides is resistance and environmental pollution, encouraging the need for natural plant products that are less toxic and environment friendly. This study was conducted to determine theacaricidal efficacy of Cassia sieberiana stem bark aqueous extract on Hyalomma species using immersion testing for egg-hatchinhibition and adult mortality. Both tests used ascending extract concentrations of 5%, 10%, 15% and 20%, at durations of 1, 2, 3, 4, 5, 6, 7 and 8 hours. Egg-hatch inhibition peaked at 5% concentration at 8hrs, 10% and 15% at 7 and 8hrs and 20% at 5, 6, 7 and 8hrs while adult mortality was highest at 20% concentration. There was a positive correlation between graded extract concentration, immersion period, egg-hatch inhibition and adult mortality. The LC50 values for adult mortality and egg-hatch inhibition were 13.1 mg/mL and 13.7 mg/mL and coefficient of determination were y = 3.7x +1.5 and y = 3.062 + 8.12 respectively. Both LC50 values were almost similar indicating a strong association between extract concentration and acaricidal activity in vitro.

Green synthesis and anthelmintic activity of silver nanoparticles using Morus Alba Fruit extract against different stages of equine strongyles.

The current study was designed to green synthesize silver nanoparticles (GRAgNPs) using Morus alba fruit extract and evaluate their nematicidal effects against strongyle nematodes compared to commercial silver nanoparticles (CAgNPs) in vitro. The nanoparticles were characterized by Ultraviolet-visual absorption spectrography, transmission electron microscopy, and X-ray diffraction. Next, uptake of AgNPs by the first stage larvae (L1), egg hatch inhibition (EHI) and the motility of infectious larvae (L3s), and the ultrastructural analysis of the eggs and worms were conducted. Moreover, some of oxidative/nitrosative stress indicators, including total antioxidant status content (TAC), protein carbonylation (PCO), lipid peroxidation (MDA), and DNA damage were assessed in the homogenized samples of strongyle L3s. We found that the GRAgNPs had spherical shape, 20-30nm in diameter with rough surface. Following incubation with GRAgNPs at concentrations of 43.40, 21.70 and 10.85 ppm and CAgNPs at concentrations of 43.40 and 21.70, EHI was more than 90%. In addition, concentrations of 43.40 and 21.70 ppm of GRAgNPs led to inhibition of larval motility by more than 90%. The LC50 at 24h of treatment for GRAgNPs and CAgNPs was determined to be 8.62 and 10.34 ppm, respectively. GRAgNPs and CAgNPs, in a concentration-dependent manner, resulted in the induction of oxidative/nitrosative stress evidenced by decreased TAC levels, and increased levels of MDA and PCO, together with increased DNA damage. The uptake of AgNPs by the L1 larvae revealed that FITC labeled GRAgNPs fluoresced with high intensity largely in the intestinal area. Scanning Electron Microscopy analysis of eggs and larvae revealed that GRAgNPs penetrated the cuticle of larvae, changed the tegmentum, and ultimately killed the worm. In conclusion, GRAgNPs had more robust anthelminthic effects than the standard antiparasitic and CAgNPs. They could be considered as a promising antiparasitic agent.

Evaluation of bromocriptine and plumbagin against the monogenean Rhabdosynochus viridisi: Computational drug repositioning and in vitro approaches

Monogeneans are parasitic platyhelminths that can harm the health of farmed fish. Few treatments are available against monogeneans, and the incentive to develop new antiparasitic agents is similar or even lower than the incentive for neglected parasitic diseases in humans. Considering that searching for and developing new antimonogenean compounds may require enormous investments of time, money, and animal sacrifice, the use of a computer-guided drug repositioning approach is a reasonable alternative. Under this context, this study aimed to evaluate the effectiveness of plumbagin and bromocriptine against adults and eggs of the monogenean Rhabdosynochus viridisi (Diplectanidae). Plumbagin is a phytochemical compound that has recently emerged as a potent antimonogenean; however, further investigation is required to determine its effects on different monogenean species. Bromocriptine was selected through a computational approach that included molecular docking analyses of 77 receptors of monogeneans (putative drug targets) and 77 ligands (putative inhibitors). In vitro experiments showed that bromocriptine does not exhibit mortality at concentrations of 0.1, 1, and 10 mg/L whereas plumbagin at 2 and 10 mg/L caused 100% monogenean mortality after 3 h and 30 min, respectively. The most effective concentration of plumbagin (10 mg/L) did not completely inhibit egg hatching. These findings underscore plumbagin as a highly effective agent against adult monogeneans and highlight the need for research to evaluate its effect(s) on fish. Although computational drug repositioning is useful for selecting candidates for experimental testing, it does not guarantee success due to the complexity of biological interactions, as observed here with bromocriptine. Therefore, it is crucial to examine the various compounds proposed by this method.

Characterization and Effect of a Nematophagous Fungus Talaromyces cystophila sp. nov. for the Biological Control of Corn Cyst Nematode.

The dynamic of plant-parasitic nematode populations in soil is closely related to soil microorganisms. Fungi from Heterodera zeae cysts were isolated to explore the phenomenon of decline in the H. zeae population in the soil. Phylogenetic study of partial ITS, BenA, CaM, and RPB2 gene sequences, in addition to morphological investigations, was utilized to identify a nematode-destroyingfungus. The nematicidal activity of a novel strain GX1 against H. zeae was assessed in vitro and in the greenhouse. Our findings revealed that strain GX1 is a new species of Talaromyces, named Talaromyces cystophila. It has a strong parasitic and lethal effect on H. zeae cysts, with 91.11% parasitism on cysts at 3 days after treatment. The contents of second-stage juveniles (J2s) and eggs inside the cysts were degraded and formed dense vacuoles, and the damaged eggs could not hatch normally. The spore suspension exhibited high nematophagous activity against nematodes, and fermentation filtrate exhibited marked inhibition of egg hatching and nematicidal activities on J2s. The hatching inhibition rates of eggs exposed to 1 × 108 CFU/ml spore suspensions or 20% 1-week fermentation filtrate (1-WF) for 15 days were 98.56 and 100%, respectively. The mortality of J2s exposed to 1 × 108 CFU/ml spore suspension reached 100% at 24 h; exposure to 50% 2-WF was 98.65 and 100% at 24 and 48 h, respectively. Greenhouse experiments revealed that the spore suspension and fermentation broth considerably decreased H. zeae reproduction by 56.17 to 78.76%. T. cystophila is a potential biocontrol strain with nematophagous and nematicidal activity that deserves attention and application.

Evaluation of some bio pesticidal plants in the management of Meloidogyne incognita

Utilization of compounds in extracts derived from medicinal plants is in vogue now for managing Meloidogyne incognita on crops owing to the unpopular use of synthetic nematicides especially in Sub-Saharan Africa. In this study, extracts from Azadirachta indica A. Juss and Hyptis suaveolens obtained using hexane, chloroform, ethyl acetate and methanol were tested for their efficacy in inhibiting egg hatching and inducing larval mortality of Meloidogyne incognita obtained from tomato bioassay maintained in Screenhouse. The extracts obtained from each solvent were reconstituted using Tween80+Dimethylsulfoxide (DMSO) and evaluated on hatching inhibition and larval mortality of Meloidogyne incognita at concentrations of 0.5%, 1.0%, and 1.5%. Furadan served as standard checks while distilled water and Tween80+(DMSO) as controls. Two separate experiments were conducted with 39 treatments each arranged in a Completely Randomized Design (CRD) with four repetitions on the laboratory bench for the hatching inhibition and larval mortality. Ninety (90) µL of each extract was added to 10 µL suspension containing either 15 eggs or second-stage larvae of Meloidogyne incognita pipette into cavity glass blocks. Hatching inhibition and larval mortality readings were recorded at 6, 12, 24, and 36 hours. Results indicated that Neem and Hyptis mixture at all concentrations extracted using any of the solvents gave 100% egg hatching inhibition from the 6th to the 36th h after treatment application. Only Neem and Hyptis mixture at 0.5% extracted in chloroform gave 100% larval mortality at the 6th h till the 36th h among the lowest concentration of the mixtures of the plant extracts. Combined solvent extracts of the two plants showed the highest activity in both hatching inhibition and larval mortality but individual solvent extracts showed the highest activity only at the highest rates used. The acute toxicity test of the most effective solvent extract of Neem and Hyptis at 0.5% extracted in Chloroform did not cause any sign of toxicity or death in the test animals.

Phytochemical analysis and in vitro anti-nemathelminthic activity of selected ethnoveterinary herbal preparations used by local healers in small ruminants of Tirunelveli district of Tamil Nadu

Small ruminants are of great significance to the Indian economy and provide living for two-thirds of the rural population. Gastrointestinal helminths of small ruminants pose a significant impact on small ruminant production. Inappropriate use of synthetic anthelminthics and very limited quantity of synthetic therapeutic agents favours the risk. Natural plant products are far more diverse than synthetic therapeutic agents and many of them have historically shown to be potential in traditional medicine in the treatment of a variety of gastrointestinal helminths. The present study was conducted in view of validating the anthelminthic activity of herbal preparations used by local healers and farmers of Tirunelveli district of Tamil Nadu. The herbal preparations used by local healers and farmers that were previously documented, was assessed for its anthelminthic activity in the current study. In vitro egg hatch assay was conducted. The study revealed a dose-dependent inhibition of egg hatching. The extracts were subjected to phytochemical analysis to evaluate the phytochemicals responsible for the activity. It was found that flavonoids, sterols, terpenoids, tannins and saponins might be accountable for the activity.

OVICIDAL AND LARVICIDAL EFFECTS OF A HYDROALCOHOLIC EXTRACT FROM Cyrtocarpa procera LEAVES AGAINST Haemonchus contortus

This study evaluated the ovicidal and larvicidal effects of a hydroalcoholic extract (HAE) and two fractions—one aqueous (Aq-F) and the other organic (EtOAc-F)—from dehydrated Cyrtocarpa procera leaves on Haemonchus contortus. In addition, the primary compounds in the HAE and the fractions were identified. The egg hatching inhibition (% EHI) and L3 larval mortality (% Mortality) tests were performed. The treatments used in the EHI test were HAE (12.5–200 mg mL-1), Aq-F (5 and 10 mg mL-1), and EtOAc-F (0.62–10 mg mL-1); for larval mortality, HAE (50–200 mg mL-1), Aq-F (20–40 mg mL-1), and EtOAc-F (2.5–40 mg mL-1). Thiabendazole (0.1 mg mL-1) and ivermectin (5 mg mL-1) were used as positive controls, while methanol (3 %) and distilled water were negative controls. The results were analyzed using a completely randomized design and an ANOVA. The main compounds in the extract and fractions were identified using high-performance liquid chromatography. The HAE had a 100 % ovicidal effect at the highest concentration tested, while EtOAc-F had a nearly 100 % ovicidal effect at 1.25 mg mL-1, and Aq-F displayed the lowest ovicidal effect. Regarding larval mortality, the HAE exerted a larvicidal effect close to 80 % at 100 mg mL-1, while EtOAc-F displayed a larval mortality of 71.47 % at 20 mg mL-1. The chemical analysis indicated the presence of gallic acid, derivatives of gallic acid (gallates), kaempferol rutinoside, quercetin glycoside, and luteolin glycoside. This study shows evidence of the ovicidal and larvicidal properties of C. procera, which could make it useful as a natural anthelmintic in the control of H. contortus.

Biological control of root-knot nematodes in common beans using putative nematocidal species of Trichoderma indigenous to Pakistan

ABSTRACT The putative nematocidal strains of Trichoderma for controlling root-knot nematodes were isolated from different agricultural fields in Pakistan. The Trichoderma isolates were confirmed using morphological and molecular characterisation. The root-knot nematodes were isolated from infected common bean plants Phaseolus vulgaris and identified as Meloidogyne incognita through phenotypic characteristics. Both in vitro and in vivo assays were performed. The nematocidal activity of the selected Trichoderma spp. was assessed using culture filtrate and spore suspension assays. Parameters including J2 mortality, egg hatching inhibition, root gall index, and egg mass index were calculated. The culture filtrates of T. bevicrassum strain ISO-03 caused significantly higher J2 mortality (71%) and inhibited egg hatching (68%) as compared to the activities of culture filtrates of the other two strains used in this study. The least control activity was observed in case of the culture filtrates of T. viride strain ISO-05 with 21% J2 mortality and 19% egg hatching inhibition. Similarly, the spore suspensions of T. brevicrassum ISO-03 showed the highest mortality of M. incognita juveniles (64% with respect to control) as well as the egg-hatching inhibition rates of 59%. In the in vivo study, the same strain T. bevicrassum ISO-03 significantly reduced the root galling index and egg mass indices as compared to the control. Furthermore, T. bevicrassum ISO-03 significantly promoted plant growth compared to the control. Overall, T. bevicrassum ISO-03 was identified as a potent biocontrol strain against root-knot nematodes in addition to its plant growth-promoting characteristics.

Efficacy of Purpureocillium lilacinum AUMC 10149 as biocontrol agent against root-knot nematode Meloidogyne incognita infecting tomato plant.

Root-knot nematode Meloidogyne incognita is among the biotic factors which has greatly affected both the yield and the quality of the tomato crop. The egg parasitic nematode, Purpureocillium lilacinum (Pl) is considered as one of the most promising agents in controlling and overcoming this plant pathogen. The nematicidal effect of the native isolate Pl AUMC 10149 on second stage juvenile's survival and egg hatching of M. incognita at different times of exposure was tested in vitro. The obtained data showed that Pl gave a maximum percentage of J2 mortality (97.6%) and egg hatching inhibition (79.8%) after 72 hours of exposure. The potentiality of Pl as well as Bio-Nematon to control M. incognita infecting tomato was conducted using different times of application in vivo. Nine treatments with five replicates were used for such bioagents compared with the nematicide Oxamyl. Each seedling was inoculated with 1000 J2s of nematode/pot and 10 mL of Pl (1x1010 CFU/mL) or Bio-Nematon spore suspension (1x108 CFU/mL) 10mL/pot. The results indicated that the most effective treatments in reducing nematode population, number of galls and egg masses of M. incognita in plant roots was performed with treatment by Pl pre-planting and post-infection with Pl (Rf 1.9) giving a significant enhancement in plant length (64.9%), fresh weight (72.52%) and shoot dry weight (163.41%) without negatively impacting environment. Therefore, the present study confirmed that using P. lilacinum AUMC 10149 can be used as a practical supplement to environmentally friendly disease management of root-knot nematodes in Egypt.

Bioactive compounds from the parasitic plant Arceuthobium vaginatum inhibit Haemonchus contortus egg hatching.

The aim of this study was to assess the in vitro ovicidal activity of an ethyl acetate extract from Arceuthobium vaginatum (EtOAc-E) and their subfractions (AvR5-AvR14) against Haemonchus contortus using the egg hatching inhibition (EHI) test. The EtOAc-E and subfractions were tested at 0.12-2.00 and at 0.015-2.0 mg/mL, respectively. Distilled water and methanol (2%) were used as negative controls and Thiabendazole (0.10 mg/mL) as a positive control. Treatments with a dependent effect on concentration were subjected to regression analysis to determine the effective concentrations (EC50 and EC90). The major secondary compounds present in the extract and subfractions were identified by high performance liquid chromatography (HPLC). The EtOAc-E and AvR9 exhibited the best ovicidal effect recording 97.5 and 100% of EHI at 0.25 mg/mL, respectively. The EtOAc-E and AvR9 displayed an EC50= 0.12 and 0.08 mg/mL, respectively. The HPLC analysis in the EtOAc-E and bioactive fractions indicated the presence of a polyphenol, glycosylated flavanones, quercetin glucoside, cinnamates, coumarin, cinnamic acid derivative, ferulic acid, coumarate, naringenin, protocatechuic acid and naringin. Results demonstrated that A. vaginatum extract and fraction is able to inhibit the egg hatch process of H. contortus and could be a viable option for the control of small ruminant haemonchosis.

Phytochemical and in vitro anthelmintic properties of mesocarp of fruit extracts from Balanites aegyptiaca (L.) Delile (Zygophyllaceae)

Introduction: Balanites aegyptiaca L. (DEL) is a plant used in Burkina Faso in traditional medicine to treat gastrointestinal parasitosis. The purpose of this study was to assess the in vitro anthelmintic activity of aqueous and hydro-ethanolic macerates (AM and HEM) of the fruit mesocarp from Balanites aegyptiaca against Haemonchus contortus. Methods: Phytochemical screening of the extracts was done using thin-layer chromatography. The egg hatch inhibition assay (EHIA) at 0.125, 0.15, 0.25, 0.625, 1.25, and 5 mg/mL and Adult worms mortality assay (AWMA) at 0.625, 1.25, 2.5, 5, 10, and 15 mg/mL concentrations were evaluated. Albendazole and levamisole were used as standards, and phosphate-buffered saline was used as a negative control. The antioxidant potential of extracts was evaluated using the ABTS [2,2’-azinobis (3-ethyl benzoin-6-sulphonate)] and DPPH (2,2-diphenyl-picrylhydrazine) methods and Fe3+ ion reducing power. The standards used were trolox and ascorbic acid. Results: Several secondary metabolites such as sterols, triterpenes, tannins, flavonoids, coumarins, and saponins were identified. For EHIA, the AM was more effective than HEM with 50% inhibitory concentrations (IC50) of 0.35 mg/mL and 0.43 mg/mL, respectively. AM was even more effective for AWMA than HEM, with 50% lethal concentrations (LC50) of 3.15 mg/mL and 8.37 mg/mL, respectively. The DPPH method gave an IC50 of 834.55 μg/mL and the capacity to reduce ferric ion (Fe3+) to ferrous ion (Fe2+) was 270.4 µmol/Ascorbic acid equivalent. Conclusion: AM and HEM from the mesocarp of B. aegyptiaca have anthelmintic properties. AM is more effective than HEM, which justifies their use with priority for AM.

Potential of 2-Hydroxyacetophenone Derivatives and Simple Phenol's for the control of Meloidogyne javanica

Objective: In this study, a series of synthetic hydroxylated (5-10) and prenylated (10-17) acetophenones, chalcones (18-20) and a flavone (21) have been synthesized and evaluated on the nematode Meloidogyne javanica. Additional phenolic compounds, including salicylic acid, isopropyl salicylate, thymol, carvacrol, cumic acid, eugenol, vanillin, and vanillic acid (22-29), were also tested. Methods: Compounds 5-21 have been synthesized by a sequence of reactions and were isolated and identified by 1H-NMR, 13C-NMR, and HRMS. The in vitro nematicidal effects of the compounds were tested on J2 juveniles. The nematicidal activity was confirmed by their egg hatching inhibition effects, tested at the minimum lethal concentration (minimum dose to give 100% J2 mortality). Results: Compounds 5-18 have been previously reported and 19-21 are described here for the first time. The 2´-hydroxylated acetophenones (5-9) showed strong nematicidal effects, being 7-9 the most active. Salicylic (22) and cumic (26) acids were effective compounds. Compounds 7, 12, 22-26, active on M. javanica J2 juveniles, were also egg hatching inhibitors. Conclusions: A C-2/C-4 dihydroxylation or C-2/C-4/C-3 trihydroxylation of the acetophenone moiety improved the activity, while introducing a hydrophilic isoprene chain (10-17) eliminated the effect, with only one prenylated acetophenone (12) being active. Among the additional phenolic compounds (22-29), these with a carboxyl group instead of the acyl side were better nematicides. These results generate molecular leads for developing new nematicidal phenolic compounds.

Anthelmintic efficacity of balanites Aegyptiaca (l.) Delile (Zygophyllaceae) almonds on three developmental stages of haemonchus contortus

Gastrointestinal nematodes are a major constraint on small ruminant farming in Burkina Faso. To overcome this, rural farmers use the Balanites aegyptiaca plant to combat gastrointestinal parasites on their family farms. The aim of this study was therefore to investigate the in vitro anthelmintic efficacy of the aqueous extract of B. aegyptiaca almonds powder against the parasitic nematode Haemonchus contortus. To this end, in vitro tests were carried out to evaluate the biological activity of the aqueous extract using five increasing concentrations over the three life stages of H. contortus by performing the tests (i) inhibition of egg hatch, (ii) inhibition of larva development and (iii) mortality of adult female worms. The results showed 21.22-80.4 %, 47.80-88.57 % and 22.20-100 % of ovicide, larvicide and vermicide rates, respectively. The effects were dose and exposition time dependent. The median lethal inhibition concentrations (IC50) were estimated to be 2.20 and 0.84 mg/ mL for the inhibitionof egg and the inhibition of larva, respectively. It can be concluded that B. aegyptiaca almonds powder has anthelmintic activity against H. contortus. However, this activity needs to be verified in vivo to reassure farmers about its use in small ruminant raising.

NEMATOCIDAL PROPERTIES OF RED SILK COTTON (Bombax costatum Pellegr. & Vuil.) FLOWER AGAINST ROOT-KNOT NEMATODE, (Meloidogyne javanica (Treub. 1885) CHITWOOD 1949

A study was conducted in Jalingo Nigeria to determine the nematocidal activity of water extract of flower powder of Bombax costatum against the eggs and J2 juveniles of Meloidogyne javanica in the laboratory. For both egg hatch inhibition and juvenile mortality, 15 Petri-dishes were used for each and were arranged in Complete Randomized Design (CRD). For egg hatch inhibition test, 500 suspended in 10 ml distilled water were dispensed into each of 15 Petri-dishes used. Five treatments used included crude extract (stock solution) of B. costatum, 5 ml, 10 ml and 15 ml dilutions and control which were also dispensed into the petri dishes. Hatched nematodes were counted after three days. For juvenile mortality test, 500 J2s suspended in 10 ml distilled water were dispensed into each of 15 Petri-dishes used. The five treatments used included crude extract (stock solution) of B. costatum, 5 ml, 10 ml and 15 ml dilutions and control which were also dispensed into the petri dishes. Dead nematodes were counted after every day for three days. Data collected was analyzed. Results showed that the 100% concentration (crude extract) treatment gave the highest egg hatch inhibition and juvenile mortality of 89.33% and 94.33% respectively. This is an indication of the potential of flower powder of B. costatum to limit these inoculums of M. javanica and therefore reduce their damage potential. Pot and field trials will be needed before can be recommended for wider use.

Laboratory Evaluation of Efficiency of some Normal and Nano Amino Acids in Hatching Eggs and Vitality of J2 Second Instar Juveniles in Root-knot Nematode Meloidogyne spp.

Tomato affected by several pathogenic factors, including root-knot nematodes (Meloidogyne spp.). This research was conducted to evaluate the efficacy of three amino acid Arginine, Serine, and Leucine, in their normal and Nano forms, at three different concentrations (10, 20, 30 ppm). The evaluation was performed under laboratory conditions to assess their effectiveness in inhibiting egg hatching and the viability Second stage Juveniles (J2) of the targeted nematode species. The laboratory results demonstrated the efficiency of all treatments in reducing the percentage of unhatched eggs, particularly at higher concentrations. The Nano-form of the three amino acids at a concentration of 30 ppm exhibited the highest efficacy compared to the normal form and showed significant superiority over the control treatment. After 72 hours, the percentage of unhatched eggs for Arginine, Serine, and Leucine Nano-amino acids was (21.00, 31.33, and 30.67), respectively, with a kill rate of (79%, 68.88%, and 69.33%) compared to the control treatment, which recorded 75% unhatched eggs and a kill rate of 25%. The impact of these treatments on the viability Second stage juveniles(J2) also varied significantly with different concentrations, showing a dose-dependent effect over time and significant differences compared to the control group. The highest concentration of 3000 ppm was the most effective, resulting in the highest kill rate for Arginine, Serine, and Leucine Nano-amino acids, which reached (95.27%, 90.27%, 88.89%), respectively, compared to the control treatment, which had a kill rate of 48.60%.

Anti-parasitic activities of four synthetic chemicals anthelmintics on Haemonchus contortus

Synthetic anthelmintic (AHs) have always been used in veterinary medicine. The increasing development of resistance to these AHs in livestock parasites threatens animal health and global production, calling into question their effectiveness. In vitro egg hatch inhibition assay (EHA) and larval development test (LDT) performed showed ovicidal and larvicidal activities of four AHs compared to the control (PBS). However, a suspicion of Haemonchus contortus resistance to Bolumisole M1 (IC50 = 0.122µg/mL) and Ivomec-D (IC50 = 0.130µg/mL) was recorded after the EHA. Similarly, resistance was observed to Bolumisole M1 (IC50 = 0.024µg/mL), Ivomec-D (IC50 = 0.07µg/mL) and Kelanthic (IC50 = 0.144µg / mL) following the LDT. These results show that cases of parasite resistance to AHs exist in small ruminants in Burkina Faso. Therefore, a reasoned use of AHs could be a good approach in the control of gastrointestinal nematodes of small ruminants in Burkina Faso. Subsequent in vivo studies should be conducted to confirm this resistance in the real conditions of these ruminants.

Valorization of the essential oil from Drypetes gossweileri S. Moore (Putranjivaceae): in vitro, in vivo, and in silico nematicidal activity

The chemical composition, insect antifeedant, in vtro/in vivo nematicidal activity, phytotoxicity, and in silico nematicidal activity of the essential oil (EO) of the African medicinal plant Drypetes gossweileri were studied. Chemical analysis using GC/MS indicated that benzyl isothiocyanate (96.23%) was the major compound, followed by benzyl cyanide (1.38%). The biocidal effects of this oil were tested against insect pests and root-knot nematodes. All the insect species tested were significantly affected by the oil according to their feeding adaptations (Spodoptera littoralis and Myzus persicae were less affected than Rhopalosiphum padi) with efficient doses (EC50) of 29.4 8.3 μg/cm2, 14.744 8.3 μg/cm2, and 8.3 μg/cm2, respectively. The oil was highly effective against juveniles J2 of the nematode Meloidogyne javanica, with LC50–LC90 values of 0.007 mg/mL–0.0113 mg/mL. D. gossweileri EO at minimum lethal concentrations (MLC) and below strongly inhibited egg hatching in vitro, whereas soil treatment caused a strong suppression of nematode population, infection frequency, and multiplication rate. The EO inhibited ryegrass (Lolium perenne) germination at 0.4 mg/mL, while at 0.1 mg/mL, its effects on germination, root and leaf growth were moderate (32.4%, 8.4%, and 18.3%, respectively). The tomato (Solanum lycopersicum) germination was not affected by the EO, but the root growth was reduced (56% at 0.1 mg/mL) at a dose 10 times higher than the LD50 calculated for M. javanica J2 mortality. Molecular docking of the nematicidal effects of the oil using PyRx revealed a strong interaction between potassium chloride transporting KCC3 (PDB ID: 7D90) and benzyl cyanide at a distance of 2.20 A° with GLN C:350, followed by benzyl isothiocyanate at a distance of 2.78 A° with ARG B:294. The in vivo nematicidal effects of D. gossweileri EO on M. javanica penetration and reproduction in tomato roots further support the potential of this EO as a nematicidal agent with insect antifeedant effects, which could be used by local farmers for crop protection.

Volatile organic compounds produced by Paenibacillus polymyxa J2-4 exhibit toxic activity against Meloidogyne incognita.

Root knot nematodes cause great damage to crops worldwide. Due to the negative effects of the application of fumigant and old chemical nematicides, biological nematicides have drawn increasing attention in recent years. Here we tested the fumigant activity of the volatile organic compounds (VOCs) blends emitted from Paenibacillus polymyxa and pure commercial VOCs against M. incognita. In this study, we investigated whether P. polymyxa strain J2-4 could produce VOCs that exhibit nematicidal activity. In vitro assays indicated that J2-4 VOCs were highly toxic to second stage juveniles (J2s) and could inhibit egg hatching. Three-layered pot experiments showed that the number of nematodes that penetrating in cucumber roots was reduced by 69.27% after the application of J2-4 VOCs under greenhouse conditions. We identified 14 volatiles using solid-phase micro-extraction gas chromatography-mass spectrometry. The efficacy of six commercially available VOCs, namely 2-isobutyl-3-methylpyrazine, 2,4-dimethoxybenzaldoxime, 2-dodecanone, 2-tridecanol, 2-tridecanone, and 2-tetradecanol, against M. incognita were examined. Except for 2,4-dimethoxybenzaldoxime, the remaining five VOCs showed strong direct-contact nematicidal activity against J2s of M. incognita, and only 2-isobutyl-3-methylpyrazine showed strong fumigant activity against J2s of M. incognita. In pot experiments, 2-isobutyl-3-methylpyrazine and 2-dodecanone reduced the number of root galls by about 70%, and 2-tridecanone reduced the number of root galls and egg masses by about 63% compared with controls. Paenibacillus polymyxa strain J2-4 exhibited high fumigant activity against M. incognita. Our results provide evidence for the use of J2-4 and its VOCs as biocontrol agents in the management of root-knot nematodes. © 2023 Society of Chemical Industry.

Nematicidal activity of <i>Ageratum conyzoides</i> leaf extract against root-knot nematode (<i>Meloidogyne javanica</i>) on eggplant in Jalingo, Nigeria

Devastation of crops by pests is exacerbated by human activities but nature provides remedies that are environmentally friendly. This study was carried out to evaluate the activity of A. conyzoides leaf extract against Meloidogyne javanica on eggplant in Jalingo, Nigeria. Three concentrations (crude extract, 5 ml and 10 ml dilutions) of extract of Ageratum conyzoides as well as control (no application) were applied on juveniles and eggs of M. javanica in petri dishes in the laboratory in 2018 and 10 ml of the same extract was applied into holes at the base of eggplants transplanted into a nematode-infested field in 2018 and 2019. Result of the juvenile mortality test showed that the extract treatments caused the mortality of M. javanica juveniles with crudes extract being highest at 90.3%. Results of the egg hatch inhibition test also showed the extract treatments significantly reduced egg hatch compared to control with crude extract having the highest inhibition of 85.5%. Field experiment in both years indicated that the extract treatments recorded significantly (P˂0.05) better result than control in all parameters in both years. There was reduced root galling and nematode reproduction and by extension final nematode population with attendant high yield in extract-treated plants. It is therefore concluded that A. conyzoides has the potential for use as a bio-pesticide against M. javanica.

Evaluation of Insecticidal Performances of Jayanti Plant (Sesbania sesban) for Integrated Control of Cabbage Caterpillar (Plutella xylostella)

The study on the use of local natural materials as a source of insecticides is intended, among other things, to reduce farmers' dependency on using synthetic chemicals. This research was conducted to obtain the most selective insecticidal active ingredient from Sesbania sesban plant for controlling cabbage caterpillars, choose a target mode of action that has a safe impact on the environment, and determine insecticidal stability during storage of the material prior to application and its stability in water after application.  The dried powder of S. sesban leaves was extracted in stages using a series of solvents, namely hexane, DCM, ethanol and water, respectively.  Each of the extract fractions produced was tested for its lethal toxicity against Plutella xylostella larvae and Diadegma semiclausum imago. Each of mortality data were processed by probit analysis to produce LC50(s) to determine their insecticidal selectivity. Subsequent bioassays were carried out using extract-water of S. sesban leaves and the data were processed by probit analysis to determine their anti-ovipositor, ovicidal powers and anti-feedant properties against P. xylostella. The insecticidal stability of S. sesban was also studied according to variations in the storage time of the simplicia before extraction, the storage time of the extract before dissolution, and its stability in water during application. The data was processed using ANOVA. The results show that the insecticidal activity of the ethanol extract fraction of S. sesban leaves for controlling cabbage caterpillars was very selective, namely very toxic to P. xylostella but very less toxic to D. semiclausum. Against P. xylostella, S. sesban leaf extract has also been proven to significantly prevent oviposition, inhibit egg hatching and feeding activity. The insecticidal power of S. sesban did not decrease significantly during storage of the simplicia for less than three months and during storage of the extract for less than seven days. However, the toxicity of the extract solution decreased drastically after 24 hours of application