Journal of Natural Pesticide Research最新文献

Early blight disease, incited by Alternaria solani, is the most deleterious foliar disease of potato and other solanaceous crops. Herein, to counter the early blight disease, T. viride (Tv), botanicals [neem (N) and garlic (G)], and fungicides [flusilazole (F) and kasugamycin (K)] in different combinations applied through tuber treatment (ST) and foliar spray (FS) were evaluated for disease suppression, germination percent, plant growth promotion, photosynthetic pigments, and yield components as well as the nutritional quality of tubers under field conditions during the 2018–2019 and 2019–2020 seasons. The results of two-year field experiments revealed that the combination of Tv+ F+ N (ST) + G+K (FS) efficiently suppressed the development of the early blight disease symptoms and recorded 21.63 and 18.37% disease severity (DS) as compared to untreated control, respectively at 30 days post-treatment (dpt). During the 2018–2019 seasons, potato tubers treated with Tv +F significantly increased tuber germination (97.78%), while Tv+ F+ N treated potato tubers exhibited 98.89% tuber germination during the 2019–2020 season. Additionally, the potato plants treated with the combination of Tv+ F+ N (ST) + G+K (FS) and challenge inoculated with A. solani positively increased plant growth promotion activities like shoot and root length, fresh and dry weight of shoot and root, number of branches/plant, and induced accumulation of photosynthetic pigments like chlorophyll-a, b, and total carotenoids content during both seasons. Furthermore, under A. solani inoculated conditions, treatment with Tv+ F+ N (ST) + G+K (FS) significantly increased all yield attributing traits and other parameters associated with tuber nutritional quality such as starch (1.79-and 1.68-fold, respectively), vitamin-C (1.51-and 1.58-fold, respectively), total nitrogen (1.31-and 1.33-fold, respectively), total phosphorus (1.53-and 1.60-fold, respectively), and total potassium content (1.42-and 1.45-fold, respectively) as compared to untreated control in both seasons. So, it can be concluded that among all the treatments, integrated treatment comprising of tuber treatment with T. viride, flusilazole, and neem extract + one foliar spray of garlic extract and kasugamycin was found very effective in reducing early blight disease, promoting the plant’s growth, and increasing the yield as well as nutritional quality of tubers in the field conditions. The inclusive results indicated that integrated application might be a sustainable and eco-friendly control strategy for potato growers to manage potato early blight and achieve higher yields and nutritional tubers.

Insects have enormous impact on public health as agricultural pests and disease vectors worldwide. Olfaction is the most crucial recognition process that mediates chemical communication in insects. Odorant binding proteins (OBP) are the small soluble proteins present in the sensory organs of the insects and are involved in many behavioural contexts, such as locating host, mating partners, escaping predators, flight, hygrosensation, immunity and identifying oviposition sites. OBPs are typically thought to function as a molecular carrier that bind, solubilize, and transport hydrophobic odorant molecules through the sensillar fluid and protect them from odorant degradation, thus maximizing olfactory system’s sensitivity. Due to their large structural and functional diversity, OBPs can be used as molecular targets for species, stage and sex specific insect pest management. In this review article, we will explore the structural and functional aspects of insect OBP and its potential applications in insect pest management. Antennal transcriptomics, ligand binding assay, olfactory repellents, pheromone-based disruption, RNA interference (RNAi) and genetic modifications can be effective management tactics for insect pests.

Application of synthetic insecticides is the most frequently used method for controlling pests. However, their indiscriminatory use has led to the development of resistance and high insecticide residues in the environment. Natural products that have low mammalian toxicity with low environmental impact, are viable alternatives to synthetic pesticides. This study aimed to evaluate the contact, fumigant toxicity, and repellent activity of Litsea cubeba essential oil (EO) and its major compound citral against Drosophila suzukii (Matsumura). The morphological alterations in target organs and microscopic damage were observed by scanning electron microscopy (SEM) and light microscopy. Contact exposure to Litsea cubeba EO at 1.0 μL/cm² resulted in mortality of 91.67% in 24 h. Fumigant toxicity assay showed that larvae mortality reached 100% when Drosophila adults were exposed to 100 μL/L Litsea cubeba EO within 24 h. Litsea cubeba EO was most repellent at 1.0 μL/cm². The symptoms caused by Litsea cubeba EO and citral on larval epidermis was uneven pigmentation and darkening of body. In the SEM images, treated Drosophila larvae exhibited a dry cuticle surface, sensory distortions, and general degeneration. The intensified cytoplasmic vacuolation and necrosis of the intestinal tract were observed in the photomicrographs with both extracts. This study showed that Litsea cubeba EO can be utilized as a bioinsecticide against Drosophila, making it an environmentally safer option for pest management in fruit and vegetable preservation.

Introduction

Malaria is a vector-borne, important public health problem spread by mosquitoes in tropical regions. The use of synthetic insecticides for mosquito control has been linked to insecticide resistance and environmental consequences. Thus, there is an urgent need to search for new highly selective and biodegradable insecticides lacking long-term toxicity to humans and mammals which are botanical-based compounds from indigenous plant sources available in local communities. Therefore, this study focused on evaluating the larvicidal activity of Aframomum angustifolium and Tagetes patula essential oils against Anopheles gambiae larvae in laboratory and simulated fields.

Methods

The Eos was extracted by the hydro distillation method, and the chemical composition of the Eos was determined using gas chromatography-mass spectrometry (GC-MS). The WHO protocol was followed for the laboratory and the simulated bioassays. Both laboratory-reared and field-collected larvae, as well as non-targeted organisms (Gambusia affinis), were used in simulated field conditions. The collected data were analyzed using probit analysis, and their means were compared in one-way analysis of variance (ANOVA) using IBM SPSS Statistic version 26.

Results

The main active ingredients in T. patula Eo were terpinolene (20.75 %) and (Z)-ocimene (17.10 %) and A. angustifolium were cis-pinen-3-ol (58.48 %) β-pinene (31.03 %). The EO of T. patula was the most efficacious in the bioassay. The larvicidal bioassay findings demonstrated that the mortality rate was dose- and exposure-dependent. In the laboratory, the EOs of A. angustifolium and T. patula have larvicidal activity against An. gambiae larvae, with LC50 values of 1.71 and 0.71 ppm after 48 h, respectively. Both binary combinations of the EOs showed synergistic interactions at 24 h but antagonistic interactions at 48 h. In the simulated field trial using laboratory-reared larvae, the mortality rate was higher in the simulated setting compared with the laboratory setting for all the tested concentrations for both EOs. Only A. angustifolium EO was toxic against Gambusia affins at 100 ppm.

Conclusion

The findings of this study have shown that T. patula and A. angustifolium oils have good larvicidal activities for An. gambiae. The two plants are potential sources of larvicidal compounds that could be used to control the malaria vector.

In sub-Saharan Africa, most food crop losses are caused by pests and diseases, prompting small-scale farmers to explore the use of botanicals as an environmentally friendly, accessible, and affordable alternative. This review presents a critical appraisal of current trends in the use of botanicals to manage crop pests and diseases in sub-Saharan Africa. A systematic search (covering January 2010 until June 2023) for eligible studies was done by exploring different databases, which yielded 13 eligible studies. An inventory of 177 plant species belonging to 54 families was recorded as botanicals used to control 28 pests and 15 crop diseases. Azadirachta indica A.Juss, Allium cepa L., and Allium sativum L. were the top-cited plants. The families with the highest reported plants were Fabaceae (27), Asteraceae (18), Solanaceae (14), and Euphorbiaceae (10). In terms of life form, the recorded plants were shrubs (40%), trees (38%), and herbs (22%). The plants were mainly used to manage pests and diseases affecting Brassica oleracea L., Solanum lycopersicum L., Zea mays L., Spinacia oleracea L., Brassica oleracea var. sabellica, and Phaseolus vulgaris L. A total of 14 plant parts were recorded, with the leaves (34%) and stem (15%) being the dominant parts used. In most cases, the preparation routes were unspecified (51%), which was followed by decoction (14%) and infusion (14%). The major method of administration was topical (55%), while approximately 39% of reports were unspecified. The pests consisted of vertebrates (28%) and invertebrates (72%) while the three (3) disease categories included fungal (77%), bacterial (17%), and viral (6%). The review revealed an ongoing dependence on the use of botanicals. However, extensive studies must be conducted that apply and adhere to good practice associated with ethnobotanical field surveys. This will aid in generating a comprehensive inventory of botanicals with potential for environmentally friendly pest and disease management.

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.

Indiscriminate use of chemical pesticides has resulted in many negative implications including degradation of the ecosystem, contamination of food products and effect on non-target organisms. Biopesticides is an efficient and ecofriendly alternative to these synthetic pesticides. Herein, we explored the efficacy of plant-extracted essential oils as a natural alternative to manage groundnut pests. Essential oils extracted from three Mentha species (M. arvensis, M. piperita and M. spicata) were detected for their chemical composition, oviposition deterrence, repellency and electrophysiological responses in groundnut bruchid, Caryedon serratus (Olivier). Gas chromatographic analysis revealed menthol (M. arvensis: 30.43%, M. piperita: 30.18%) and carvone (M. spicata: 65.58%) as the most abundant component in essential oils. Among all the four tested concentrations for the three mentha oils the most significant oviposition deterrence was seen in M. spicata (2% v/w) which completely inhibited oviposition followed by 1.5% M. piperita (21 ± 1.53; p < 0.01), 1.5% M. spicata (28 ± 0.58; p < 0.01) and 1.0% M. arvensis (35 ± 0.58; p < 0.01) oil treated groundnuts after 24 h. M. piperita (86%, ♀) and M. arvensis (70%, ♀) showed promising repellence against the females. In contrast, M. spicata was found to be a potent (90%, ♂) male repellent during olfactometer bioassays. Coupled gas chromatography electroantennogram (GC-EAG) revealed consistent sensory deflections in the antennae of female C. serratus from all the three oils. Our findings revealed promising oviposition deterrence and repellent properties of these mentha oils which offers a prospect in developing effective repellent and its application in integrated pest management, safety of human health, environment and agricultural productivity.

Natural products are in the spotlight of novelty for obtaining ecofriendly agents against pests. In this context, searching for new antifungal alternatives for control of grain microorganism is recommended. In this paper we show a brief description of nanoemulsification as a valuable tool for modification of essential oil properties. Low energy method was used for the preparation of Eugenia sulcata nanoemulsion. This approach was also used for the preparation of this type of colloid with β-caryophyllene, the main component of this essential oil. Especially regarding Aspegillus parasiticus, it was possible to observe increment of bioactivity by nanoemulsification of E. sulcata. This short communication contributes to better knowledge of mechanism in the rationalization of antifungal nanoemulsions based in essential oil and its main constituents, providing relevant insights that can be used for other complex volatile mixtures.

Vector management is an important challenge and burden to developing countries. Frequent and indiscriminate application of chemical insecticides for vector control has resulted in the development of resistance and undesirable effects on beneficial organisms. Hence an alternative approach is needed for the mosquito control programme. The present study investigated the insecticidal activity and spectral analysis of Ocimum canum methanol leaf extract against three mosquito species. One out of four fractions (F1-F4), the 4th fraction, revealed showed good insecticidal activity in larva and adult Cx. quinquefasciatus, Ae. aegypti and An. stephensi (0.114, 0.325 and 0.173 ppm) and (1.798, 1.061 and 0.871 ppm). The mortality was found to be dosage dependant. Spectral analysis of ¹H NMR and ¹³C NMR indicates the presence of 6 protons at δH value of 7.45 (s) and 3 protons at δH value of 7.85 (s) ppm. FT-IR identified the possible band near the capping region at 3417.16 cm^-1. LC-MS confirmed the eugenol compound with 99.79% purity at the molecular weight of 164. Further, eugenol docking analysis revealed high homology similarity with insect odorant binding protein 3OGN and AchE protein 2BG9. Overall, the result suggests that isolated eugenol compounds were found to be effective for the eco-friendly management of mosquito vectors. These findings could be useful for designing an efficient mosquitocidal compound in the future.

Ginger essential oil (Zingiber officinale) is the volatile oil extracted from ginger rhizome. Compared to chemical synthetic repellent, green insect (in particular mosquito) repellent would be favoured by the public as it is environmentally friendly and does not cause harm to the human’s health. The focus of this study is on the comparison study between China Ginger and Kuching Local Ginger essential oil aim towards utilization as the greener mosquito repellent. In this study, the ginger essential oils are extracted greener method i.e. via hydro distillation process for 7 h. The percentage oil yield for China and Kuching Local Ginger are 0.158 wt% and 0.264 wt%, respectively. The extracted ginger essential oils are further subject to Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography- Mass spectrometry (GC-MS) analysis. Based on the FTIR spectrum graph generated, both types of ginger essential oils essentially having the similar function groups including phenolic compounds, alcohol primer, alkena methyl group, aromatic compound, carbonyl compound, carboxylic acid, hydroxyl group. From the GC-MS results it revealed that the most abundant chemical constituents presented in both China Gniger and Kuching Local Ginger essential are: α-Zingiberene (7.88% and 7.03%), α-Curcumene (6.04% and 6.49%), α-Citral or Genarial (3.81% and 7.86%), β-Bisabolene (3.06% and 4.62%), β-Sesquiphellandrene (5.83% and 5.95%), β-Sesquisabinene (0.07% and 0.51%), β-Selinenol (3.97% and 2.26%), Zingiberenol (5.16% and 1.64%), [6]-Shogaol (0.33% and 0.23%), trans-Sesquisabinene hydrate (1.72% and 2.87%), trans-Geranylgeraniol (3.51% and 2.81%), Camphene (1.17% and 0.56%), Eucalyptol (2.68% and 1.81%), Citronellol (1.76% and 1.55%), Neral (2.82% and 6.03%), and Geraniol (1.62% and 2.29%) respectively. Kuching Local Ginger essential oil is found marginally superior insect repellent characteristics due to its higher monoterpene compounds in the essential oil.