Journal of Natural Pesticide Research最新文献

Brinjal shoot and fruit borer (BSFB) is a notorious pest of brinjal. This study evaluates some microbe and plant origin bio-pesticides alone or in combination with Bacillus thuringiensis var. kurstaki 5 % (Btk 5 %) in the brinjal field to combat against BSFB. We found that application of biopesticides in combination with Btk 5 % increased the control of BSFB that results increased marketable yield, gross yield, individual fruit weight compared to their application without Btk 5 %. Among the biopesticide combinations, Abamectin 1.2 % + Emamectin benzoate 1 % and Btk 5 % as well as Emamectin benzoate 1 % and Btk 5 % were potent in context to BSFB control and yield attributes. These combinations confirmed 78.04 % and 74.76 % shoot infestation control, 70.90 % fruit infestation reduction in number basis, 72.40 % and 72.18 % fruit infestation control in weight basis, 13.56 ton ha⁻¹ and 11.41 ton ha⁻¹ marketable yield, 15.59 ton ha⁻¹ and 12.37 ton ha⁻¹ gross yield, respectively. In contrast, Abamectin 1.2 % + Emamectin benzoate 1 % and Emamectin benzoate 1 % confirmed 58.18 % and 67.96 % shoot infestation control, 50.27 % and 62.06 % fruit infestation reduction in number basis, 51.86 % and 59.24 % fruit infestation control in weight basis, 9.05 ton ha⁻¹ and 9.44 ton ha⁻¹ marketable yield, 11.82 ton ha⁻¹ and 10.83 ton ha⁻¹ gross yield. These promising bio-pesticide combined with Bt also ensure more individual fruit weight compared to without Bt. These results thus illustrated that application of Btk 5 % along with bio-pesticide increases their efficacy because of the synthesis of insecticidal toxins named Cry, Vip, and Cyt by Btk 5 % that have synergistic effect with biopesticides and kill insects.

The objective of this study was to evaluate the antifungal activity (AA) of essential oils (EOs) extracted from Eucalyptus globulus Labill. (Eucalyptus), Citrus limonum (L.) Burm. (Lemon), Cinnamomum zeylanicum Blume. (Cinnamon), Lavandula latifolia aspic (Lavender), Rosmarinus officinalis L. (Rosemary), and Mentha spicata L. (Peppermint) against four pathogenic fungi responsible for grapevine trunk diseases in Moroccan vineyards. The EOs with the highest in vitro efficacy were selected for further testing on autoclaved grape wood assays against Diplodia mutila, Neoscytalidium novaehollandiae, Trichothecium roseum, and Neopestalotiopsis vitis. The major chemical constituents of the tested EOs were determined through GasChromatography–Mass Spectrometry (GC-MS) analysis, and their relative percentages were recorded. All tested EOs demonstrated significant antifungal activity against the four pathogens, as evidenced by in vitro results. Redundancy analysis (RDA) confirmed the efficacy of the tested EOs against grapevine fungal pathogens. The efficacy of each EO varied depending on the pathogen being targeted. For example, lavender had the highest efficacy across EOs (81.37%) against T. roseum, while peppermint was the most effective in inhibiting D. mutila (47.45%). Cinnamon was the most effective EO in controlling N. vitis (73.33%), while rosemary had the best effect in controlling N. novaehollandiae (56.79%), with the most effective EC₅₀ value (8.66 µL/ml) being attributed to the rosemary EO. The in vitro results were further confirmed through autoclaved grape wood assays, with inhibition of proliferation ranging between 93.14% and 66.32%. These findings represent a novel application of EOs extracted from various medicinal plants to control fungal diseases in grapevine plantations.

Mirid bugs (Hemiptera: Miridae) represent a significant challenge for greenhouse cash crops like cucumber, tomato and eggplants, leading to huge economic losses. This study investigated the potential of the entomopathogenic nematode (EPN) Steinernema carpocapsae as biological control agent of the mirid bug species Lygus rugulipennis, Liocoris tripustualtus, and Macrolophus pygmaeus through aerial spray application under laboratory and greenhouse conditions (only for L. rugulipennis and M. pygmaeus). The laboratory trials showed a significant effect of S. carpocapsae on the average survival rate of the three mirid species. The highest efficacy was found for subadults of L. rugulipennis (50%), followed by M. pygmaeus (25%) and L. tripustulatus (15%). Microscopic dissections showed that EPNs can infect all studied mirid species and life stages. Under greenhouse conditions, a significant difference was observed between developmental stages, with no significant effect for adults, but an efficacy of 19% and 32% for nymphs of L. rugulipennis and M. pygmaeus, respectively. These results highlight the potential of EPNs in the control of problematic mirid bugs in greenhouse vegetable production, which could lead to a reduction in the use of synthetic pesticides and promote more sustainable agricultural practices.

Bacterial wilt caused by Ralstonia solanacearum can cause up to 100% yield loss in tomato production and has compelled many farmers to abandon previous productive farms. Consequently, the absence of an effective control method demands an intensive such for a functional management option. The study was carried out to evaluate the efficacy of microbial antagonists in managing bacterial wilt under field conditions. The experiment was laid down under Randomized Complete Block Design and four replicates maintained for each treatment. Antagonistic strains of locally isolated Trichoderma hamatum, T. atroviride, T. harzianum, Bacillus subtilis, Serratia spp., and Acinetobacter spp. were assessed. Commercial formulations of T. viride (Bio Cure F®) and Pseudomonas fluorescence (Bio Cure B®) were included as standard checks. Treatment application was initiated at transplanting by drenching the rhizosphere with 50 ml of the inoculum. Application was repeated every two weeks until tenth week after transplanting. Data was collected on plant stand count, disease incidence, disease severity, plant height, plant biomass, and fruit weight. Trichoderma hamatum was the most effective in experiment 1, reducing crop mortality, incidence and AUDPC by up to 51.7%, 49.3% and 58.2%, respectively. It also exhibited the highest percentage yield increase by up to 196.4% compared to the untreated control. In contrast, B. subtilis showed superior disease suppression in experiment 2, reducing crop mortality, incidence and AUDPC by up to 44.6%, 48.5% and 51.0%, respectively. It also increased biomass by approximately 62.0% in both experiments. It was closely followed by Serratia spp., which also gave the highest yield output in experiment 2 of up to 233.0%. These findings suggest that novel antagonistic strains T. hamatum and B. subtilis presents unique opportunities for exploiting local microbial resources as biocontrol products. These products can be incorporated as part of an integrated bacterial wilt management program in farms where production is significantly affected by the disease.

The limitations encountered with chemical insecticides to control mosquito borne diseases and proliferation of mosquitoes, has prompted the researchers to focus on developing insecticides of botanical origin. Acetone and methanol extracts of three medicinal plants were tested against the first instar of Culex quinquefasciatus and the lethal concentrations estimated. The column fractions of methanol extracts of the selected plants, Andrographis paniculata, Polyalthia longifolia and Bougainvillea spectabilis exhibited significant larvicidal activities. The 24 hr LC₅₀ of the methanol-ethyl acetate (MeOH-EA) 4:1column fractions of A. paniculata and P. longifolia and nHexane-ethyl acetate (nH:EA) 5:5 fraction of B. spectabilis are 3.013, 145.67 and 221.38 ppm, respectively. The effective concentration which affects 50% emergence (EC₅₀) of the treated larvae is 1.05 ppm, 72.6 ppm and 110.693 ppm respectively for the active column fractions. Total developmental duration and growth index were also affected by the column fractions. Exposure of the sub lethal dose affect the gonotrophic cycle of Cx. quinquefasciatus and also exhibited more than 90% control of reproduction in the tested group of treated males with untreated females (T♂ x UT♀) and exhibited higher sterility index. Dissection of the ovary and testes of Cx. quinquefasciatus after treatment with column fractions shows that the testicular development was drastically affected. The testes and ovaries of the treated mosquitoes showed variation in length and size and number of ovarioles when compared to control mosquitoes. The tested botanicals at comparatively lower dosages could effectively interfere with reproductive viability and check proliferation in next generation.

Losses resulting from pest arthropods and plant or animal parasites present a significant threat to food security. The primary method for managing pests and parasites involves the use of pesticides and synthetic drugs. Nonetheless, these substances have raised concerns due to their detrimental effects on health and their decreasing effectiveness against resistant pests. Consequently, there is a growing interest in adopting more sustainable control methods. An alternative approach to pest control involves utilizing natural substances, specifically plant-derived molecules. Cysteine proteases (CPs), a type of hydrolase found in certain fruits and latex of plants like pineapple, papaya, kiwi, and fig, offer potential in this regard. These enzymes are renowned for their diverse industrial applications owing to their chemical properties. However, their application for controlling plant pathogen nematodes, insect pests, and animal parasites has received limited exploration. In this review, we examine several documented studies that highlight the potential of CPs in the control of these pests and parasites.

Mosquitoes are major disease-causing vectors. Control of adult mosquito vectors by synthetic chemical applications leads to chemical resistance and causes environmental pollution. Commercially available mosquito chemical-coils also provide health hazards like respiratory diseases probably to a larger extend than plant-based bio-coils. In our study laid smoke-exposed gravid females of C. quinquefasciatus a lower number of eggs, egg hatchability were also comparatively lower and the progeny production during the F1 generation was significantly lower. In the present study there was an 84.39% reduction of the population of bio-coil exposed mosquitoes compared to 90.13%, after the use of a chemical-coil. LC₅₀ of bio-coil extract ranged from 201.595 ppm to 374.395 ppm. LC₅₀ of achemical-coil extract ranged from 209.747 ppm to 296.307 ppm. Predation efficiency was lower in with chemical-coil treated aquatic environments than at bio-coil extract exposed breeding sites of C. quinquefasciatus. The predation efficiency against C. quinquefasciatus was 22.1% (I) with chemical-coil and 11.4% (II) with bio-coil in a natural setting, whereas it was 42.7% (I) and 22% (II) in the laboratory, respectively. Very low concentrations of bio-coil increased the predation on young mosquito instars where predators and prey co-exist. The feeding efficiency of Poecilia reticulata in the control environment was 62.3% and 53.9% for the 1st and 2nd instar larval population.There was an increase in fish predatory responses with bio-coil extract against mosquito 1st and 2nd larval instars and its predatory efficiency was 74.1% and 68.4%, respectively, whereas it was much lower with the chemical-coil with 56.5% and 46.9%, respectively. Marker antioxidant enzymes lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT) from the gill region of P. reticulata were not affected by bio-coil extract but increased substantially with chemical-coil. Bio-coil extract also inhibited the growth of several bacterial pathogens.

The aim of this work was to evaluate the effectiveness of partially purified Iturin A and cell free supernatant (CFS) produced by the Bacillus subtilis strain ET-1 on control of powdery mildew. For this purpose, B. subtilis ET-1 strain was grown in a 21-L stirred-tank bioreactor with 10 litres of an already designed substrate for the production of Iturin A named High Medium Broth (HMB). At the end of culture, an Iturin A amount of 396.86 mg L^-1 was determined in the supernatant purified from the cells by centrifugation. Then, the effect of CFS against the cucurbit powdery mildew fungus, Podosphaera xanthii was assessed on plants of Cucumis melo L. (cv Amarillo Oro) in greenhouse and in open-field conditions. For the greenhouse experiments, three different dilutions of supernatant containing 400, 40 and 4 mg L^-1 Iturin A were used. Significant dose-dependent control effects were observed. In particular, a control disease of 100% was achieved at the highest concentration tested. In the subsequent open-field trials, a crude lipopeptide extract obtained by acid precipitation was analysed in addition to the CFS. The two conditions were tested at intermediate concentrations containing 100 ppm of Iturin A on plants artificially inoculated with P. xanthii and both showed strong disease control, similar to that observed with chemical fungicide. In conclusion, the results of the present work, while needing further study, open promising scenarios in the use of microbial lipopeptides, like Iturin family, as alternative control agents of plant diseases.

Tomato fusarium wilt disease is an important soil-borne disease caused by Fusarium oxysporum f. sp. Lycopersici (FoL) worldwide. The disease causes yield losses of about 90% worldwide. This study aimed to evaluate the extracts of C. swynnertonii (resins) and S. glaucescens (latex, fresh and dry leaves) for their efficacy against FoL. In the laboratory, a 4 × 4 factorial experiment in a Complete Randomized Design (CRD) was carried out to evaluate resins, latex, fresh, and dry leaves each in four concentrations (0.01 g/ml, 0.05 g/ml, 0.1 g/ml and 0.15 g/ml). The negative and positive controls were Sterile Distilled Water (SDW) and a Linkmil 72 WP (Mancozeb 64% + Metalaxyl 8%) respectively. In a screenhouse, resins, latex, and fresh and dry leaves, each at 0.15 g/ml were applied on pre-inoculated tomato plants to manage TFW disease. The experiment was laid out in a Randomized Complete Block Design (RCBD) with four replications. The negative and positive controls were the untreated soil and soil treated with Linkmil 72 WP respectively. The differences between extracts in the inhibition of radial mycelial growth of the pathogen were highly significant (p = 0.000). The efficacy of the plant extracts against in vitro growth of FoL was significantly dependent on the application dose. The inhibition of mycelial growth caused by latex and dry leaves was higher than that of Linkmil 72 WP (23.58%) and SDW (0%) by 41% and 65% respectively. Findings show that there was a TFW disease reduction of 72.92% 68.75% and 56.25% in plants treated with dry leaves, the latex of S. glaucescens, and resin of C. swynnertonii in that order. Plant extracts had significant effects (p = 0.000) on plant growth. The plants treated with dried leaf powder attained the highest height, the number of branches/plant, leaves/plant, and leaf area of 85.85 cm, 19.25,99.5 and 59.39 respectively. The findings benchmark the fungicidal potential of C. swynnertonii and S. glaucescens.

Fire blight of pear trees is a devastating disease which is caused by the bacterium namely as Erwinia amylovora (Burrill 1882). Current chemical control methods employed for fire blight disease are periodic applications of copper compounds and streptomycin, especially when environmental conditions are favorable for the infection. Silver nanoparticles (SNPs) are nanoparticles of silver with 1–100 nm size, which are synthesized via different chemical and biological methods. They have been shown to have antibacterial activity against many human and animal pathogens. In this study, silver nanoparticles (SNPs) with an average size of about 25 nm were determined using quince petal aqueous extract. The physicochemical properties of the resulting SNPs were characterized using UV–Vis spectroscopy, X-ray diffraction technique (XRD), transmission electron microscope (TEM), energy dispersive X-ray (EDAX) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). The SNPs inhibited the growth of E. amylovora in culture media and in-planta. The disease severity was reduced by 80 % and 74 % in pear blossoms and immature fruits treated with 100 μg/mL SNP solution, respectively. This work demonstrates that Cydonia oblonga petal extract is a feasible medium for the synthesis of silver nanoparticles which can be used for the control of fire blight disease.