Goldenseal (Hydrastis canadensis L.) Extracts Inhibit the Growth of Fungal Isolates Associated with American Ginseng (Panax quinquefolius L.).

American ginseng, a highly valuable crop in North America, is susceptible to various diseases caused by fungal pathogens, including Alternaria spp., Fusarium spp., and Pestalotiopsis spp. The development of alternative control strategies that use botanicals to control fungal pathogens in American ginseng is desired as it provides multiple benefits. In this study, we isolated and identified three fungal isolates, Alternaria panax, Fusarium sporotrichioides, and Pestalotiopsis nanjingensis, from diseased American ginseng plants. Ethanolic and aqueous extracts from the roots and leaves of goldenseal were prepared, and the major alkaloid constituents were assessed via liquid chromatography-mass spectrometry (LC-MS). Next, the antifungal effects of goldenseal extracts were tested against these three fungal pathogens. Goldenseal root ethanolic extracts exhibited the most potent inhibition against fungal growth, while goldenseal root aqueous extracts and leaf ethanolic extracts showed only moderate inhibition. At 2% (m/v) concentration, goldenseal root ethanolic extracts showed an inhibition rate of 86.0%, 94.9%, and 39.1% against A. panax, F. sporotrichioides, and P. nanjingensis, respectively. The effect of goldenseal root ethanolic extracts on the mycelial morphology of fungal isolates was studied via scanning electron microscopy (SEM). The mycelia of the pathogens treated with the goldenseal root ethanolic extract displayed considerable morphological alterations. This study suggests that goldenseal extracts have the potential to be used as a botanical fungicide to control plant fungal diseases caused by A. panax, F. sporotrichioides, or P. nanjingensis.

Acaricidal and Insecticidal Activities of Essential Oils and Constituents of Tasmannia lanceolata (Poir.) A.C.Sm. (Canellales: Winteraceae) Against Tetranychus urticae Koch (Trombidiformes: Tetranychidae) and Myzus persicae Sulzer (Hemiptera: Aphididae).

The negative side effects of synthetic pesticides have drawn attention to the need for environmentally friendly agents to control arthropod pests. To identify promising candidates as botanical pesticides, we investigated the acaricidal and insecticidal activities of 44 plant-derived essential oils (EOs) against Tetranychus urticae Koch and Myzus persicae Sulzer. Among the tested EOs, Tasmannia lanceolata (Poir.) A.C.Sm. (Tasmanian pepper) essential oil (TPEO) exhibited strong acaricidal and insecticidal activity. Mortality rates of 100% and 71.4% against T. urticae and M. persicae, respectively, were observed with TPEO at a concentration of 2 mg/ml. Polygodial was determined to be the primary active component after bioassay-guided isolation of TPEO using silica gel open-column chromatography, gas chromatography, and gas chromatography-mass spectrometry. Polygodial demonstrated acaricidal activity against T. urticae with mortality rates of 100%, 100%, 61.9%, and 61.6% at concentrations of 1, 0.5, 0.25, and 0.125 mg/ml, respectively. Insecticidal activity against M. persicae was also evident, with mortality rates of 88.5%, 85.0%, 46.7%, and 43.3% at respective concentrations of 1, 0.5, 0.25, and 0.125 mg/ml. Insecticidal and acaricidal activities of TPEO were greater than those of Eungjinssag, a commercially available organic agricultural material for controlling mites and aphids in the Republic of Korea. These findings suggest that TPEO is a promising candidate for mites and aphids control.

Insecticidal Activities Against Odontotermes formosanus and Plutella xylostella and Corresponding Constituents of Tung Meal from Vernicia fordii.

The environmental pollution, pesticide resistance, and other associated problems caused by traditional chemical pesticides with limited modes of action make it urgent to seek alternative environmentally-friendly pesticides from natural products. Tung meal, the byproduct of the detoxified Vernicia fordii (Hemsl.) seed, has been commonly used as an agricultural fertilizer and as a pesticide. However, its active insecticidal extracts and ingredients remain elusive. In the present study, the contact toxicities of tung meal extracts against the agricultural and forest pests like O. formosanus and P. xylostella were examined. Our results showed that ethyl acetate and petroleum ether extracts showed the strongest toxicity against O. formosanus and P. xylostella, respectively. In order to further explore the chemical profiles of the ethyl acetate and petroleum ether extracts, UPLC-Q/TOF-MS and GC-MS analyses have been performed, and 20 and 29 compounds were identified from EA and PE extracts, respectively. The present study, for the first time, verified the noteworthy insecticidal activities on the aforementioned agricultural and forest pesticides and revealed the potential active parts and chemical composition, which are conducive to further exploiting the potential of tung meal as a natural plant-derived insecticide for biological control of agricultural and forest pests.

Ascaridole-rich essential oil from marsh rosemary (Ledum palustre) growing in Poland exerts insecticidal activity on mosquitoes, moths and flies without serious effects on non-target organisms and human cells.

Marsh rosemary (Ledum palustre, Ericaceae) has been widely used in the traditional medicine of various regions worldwide, and as insect repellent. Little is known on its essential oil insecticidal potential. This study explored the insecticidal effects of the essential oil obtained from L. palustre growing in Poland on selected insect pests and vectors. GC-MS analysis evidenced an uncommon chemotype characterized by ascaridole (35.3% as sum of cis-ascaridole and isoascaridole) and p-cymene (25.5%). The essential oil was effective against Culex quinquefasciatus, Spodoptera littoralis and Musca domestica, showing LC50/LD50 of 66.6 mg L-1, 117.2 µg larva-1 and 61.4 µg adult-1, respectively. It was not toxic to non-target Eisenia fetida earthworms and moderately toxic to Daphnia magna microcrustaceans, over the positive control α-cypermethrin. The essential oil cytotoxicity on human keratinocytes and fibroblasts showed high IC50 values (71.3 and 84.4 µg mL-1, respectively). Comet assay data highlighted no DNA damages. Based on our findings, this essential oil, characterized by the ascaridole/p-cymene chemotype, could be a candidate for the formulation of botanical insecticides; large-scale production of green insecticides by this rare species may be assured by ex situ cultivation and biotechnological techniques.

Bioactivity of Common Pesticidal Plants on Fall Armyworm Larvae (Spodoptera frugiperda).

The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is a recent invasive pest species that has successfully established across sub-Saharan Africa where it continues to disrupt agriculture, particularly smallholder cereal production. Management of FAW in its native range in the Americas has led to the development of resistance to many commercial pesticides before its arrival in Africa. Pesticide use may therefore be ineffective for FAW control in Africa, so new and more sustainable approaches to pest management are required that can help reduce the impact of this exotic pest. Pesticidal plants provide an effective and established approach to pest management in African smallholder farming and recent research has shown that their use can be cost-beneficial and sustainable. In order to optimize the use of botanical extracts for FAW control, we initially screened ten commonly used plant species. In laboratory trials, contact toxicity and feeding bioassays showed differential effects. Some plant species had little to no effect when compared to untreated controls; thus, only the five most promising plant species were selected for more detailed study. In contact toxicity tests, the highest larval mortality was obtained from Nicotiana tabacum (66%) and Lippia javanica (66%). Similarly, in a feeding bioassay L. javanica (62%) and N. tabacum (60%) exhibited high larval mortality at the highest concentration evaluated (10% w/v). Feeding deterrence was evaluated using glass-fibre discs treated with plant extracts, which showed that Cymbopogon citratus (36%) and Azadirachta indica (20%) were the most potent feeding deterrents among the pesticidal plants evaluated. In a screenhouse experiment where living maize plants infested with fall armyworm larvae were treated with plant extracts, N. tabacum and L. javanica were the most potent species at reducing foliar damage compared to the untreated control whilst the synthetic pesticide chlorpyrifos was the most effective in reducing fall armyworm foliar damage. Further field trial evaluation is recommended, particularly involving smallholder maize fields to assess effectiveness across a range of contexts.

Acaricidal efficacy of Calotropis procera (Asclepiadaceae) and Taraxacum officinale (Asteraceae) against Rhipicephalus microplus from Mardan, Pakistan.

Medicinal plants are used by traditional folk healers, modern physicians, and veterinarians as an alternative to conventional drugs to treat a wide range of disorders including parasitic diseases. Some compounds from these plants have been shown to have acaricidal activity and repel arthropods. The cattle tick Rhipicephalus microplus is one of the most destructive pests to the livestock industry in tropical and subtropical parts of the world. The potential to develop herbal acaricides to control R. microplus infestations is critical in maintaining cattle herd productivity, reducing economic losses, and curtailing the overuse of synthetic chemical acaricides. Calotropis procera, the apple of Sodom, and Taraxacum officinale, the common dandelion, were evaluated for acaricidal activity against R. microplus larvae and adults in vitro. Both plant species tested are common indigenous species of Pakistan where R. microplus infestations are widespread across livestock species including cattle, sheep, and goats. Whole-plant extracts derived from C. procera and T. officinale significantly reduced the index of egg laying (P < 0.01) and increased the percent inhibition of oviposition of adult female ticks at a concentration of 40 mg/mL when assessed by the adult immersion test (AIT). Calotropis procera and T. officinale treatments at the same concentration also resulted in larval mortality of 96.0% ± 0.57 and 96.7% ± 0.88, respectively, as measured using the larval packet test (LPT). An increasing range of extract concentrations was tested to determine the LD50 and LD90 for C. procera, 3.21 and 21.15 mg/mL, respectively, and T. officinale, 4.04 and 18.92 mg/mL, respectively. These results indicate that further studies are warranted to determine the relative contribution of individual phytochemicals from whole-plant extracts on acaricidal activity. This information will guide the design of further acaricidal efficacy tests using livestock infested with R. microplus.

High toxicity of camphene and γ-elemene from Wedelia prostrata essential oil against larvae of Spodoptera litura (Lepidoptera: Noctuidae).

The development of eco-friendly biopesticides in the fight against agricultural pests is an important challenge nowadays. The essential oil of Wedelia prostrata Hemsl. is known for its multipurpose biological activities in Chinese folk medicine. However, limited efforts attempted to understand the potential insecticidal activity of its main individual constituents and related mechanism of action. In this research, we investigated the insecticidal activity of W. prostrata against the crop pest Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Toxicity on 4th instar larvae was assessed after 24 h of exposure. The LC50 and LC90 of the W. prostrata essential oil were 167.46 and 322.12 µg/ml, respectively. GC-MS analyses were carried out to shed light on the oil chemical composition. Main constituents were the monoterpene camphene (9.6%) and the sesquiterpenes γ-elemene (7.6%), α-humulene (6.9%), and (E,E)-α-farnesene (7.3%). The pure constituents were evaluated for their insecticidal activity on S. litura 4th instar larvae. The most toxic molecule was camphene (LC50 = 6.28 µg/ml), followed by γ-elemene, (LC50 = 10.64 µg/ml), α-humulene (LC50 = 12.89 µg/ml), and (E,E)-α-farnesene (LC50 = 16.77 µg/ml). Overall, our experiments highlighted the promising potential of camphene and γ-elemene from W. prostrata essential oil against larvae of S. litura, allowing us to propose these two compounds for the development of newer pesticides in the fight against crop pests. Further studies aimed at evaluating the potential synergy between these two molecules, as well as their stability in field conditions are ongoing.

Insecticidal activities of constituents of Litsea cubeba fruit extracts effective against the maize weevil (Coleoptera: Curculionidae).

In this study, we investigated the insecticidal activities, including contact toxicity, fumigant toxicity, and repellent activity, of Litsea cubeba fruit extracts against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The extracts, obtained by liquid-liquid extraction in n-hexane, ethyl acetate, chloroform, and water were analyzed by gas chromatography-mass spectrometry. Among the different extract types, chloroform extracts exhibited the strongest repellent, contact, and fumigant activities against S. zeamais. The main components of the chloroform extracts were identified as laurine (21.15%) and 2,6-diisopropyl aniline (16.14%), followed by chlorobutanol (10.54%), 3-O-methyl-N-acetyl-d-glucosamine (10.03%), and 6-methyl-5-hepten-2-one (8.33%). Among the identified components of the chloroform extracts, chlorobutanol showed the strongest fumigant toxicity (LD50 = 21.91 mg/liter), contact toxicity (LD50 = 54.25 µg/adult), and repellent activity against S. zeamais. These results indicate that L. cubeba fruit extracts possess natural insecticide-like activities against S. zeamais.

The use of Clausena anisata in insect pest control in Africa: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Clausena anisata is used traditionally by various communities across Africa against pests such as mosquitoes, flies and weevils among others. Pests are a major cause of disease and production losses in various crop and livestock production systems in Africa. This review discusses the available information on the occurrence, chemistry, biological activity and possible commercialization of Clausena anisata with a view to see the plant species being integrated in pest management. MATERIALS AND METHODS: Information on the ethnomedical use, chemistry and biological activity of C. anisata published between 1980 and 2016 was accessed from various databases namely Science Direct, Springer Link and Wiley Online Library. In addition various relevant books were also consulted. RESULTS: The crude extracts as well as different fractions of C. anisata have been evaluated for activity against various insect pests and have been shown to be active. Furthermore, close to 50 compounds have been isolated and identified from C. anisata, which include coumarins, carbazole alkaloids, limonoids and essential oils (monoterpenes). Some of these compounds have been proven to exhibit pesticidal properties in both laboratory and field studies against various pests including mosquitoes, flies and weevils. The possible mechanisms of action of these compounds have been explored in this review. CONCLUSION: The results of pesticidal and phytochemical screening of C. anisata strongly indicate that the species is endowed with pesticidal properties that can be harnessed into commercial products. However, one glaring challenge in the evaluation of this plant species for pesticidal activity has been the non-availability of standard testing systems. Researchers have used various methods which they developed based on their own circumstances and resources. Formulation, standard appropriate testing systems and agronomic research are key in unlocking the potential of this important African species.

Use of plant extracts for tea pest management in India.

India is the second largest producer of black tea in the world. The biggest challenge for tea growers of India nowadays is to combat pests and diseases. Tea crop in India is infested by not less than 720 insect and mite species. At least four sucking pests and six chewing pests have well established themselves as regular pests causing substantial damage to this foliage crop. Various synthetic pesticides are widely used for the management of tea pests in India. Applications of such large quantity of pesticides could cause various problems such as development of resistance, deleterious effects on non-target organisms such as insect predators and parasitoids, upsetting the ecological balance, and accumulation of pesticide residues on tea leaves. There is a growing demand for organic tea or at least pesticide residue free tea in the international market which affects the export price. There is also a higher emphasis of implementation of new regulations on internationally traded foods and implementation of Plant Protection Code (PPC) for tea by the Government of India. This necessitates a relook into the usage pattern of synthetic pesticides on this crop. There are various non-chemical interventions which are being worked out for their sustainability, compatibility, and eco-friendly properties which can gradually replace the use of toxic chemicals. The application of plant extracts with insecticidal properties provides an alternative to the synthetic pesticides. Botanical products, especially neem-based products, have made a relatively moderate impact in tea pest control. Research has also demonstrated the potential of 67 plant species as botanical insecticides against tea pests. The majority of plant products used in pest management of tea in India are in the form of crude extracts prepared locally in tea garden itself, and commercial standardized formulations are not available for most of the plants due to lack of scientific research in the area. Apart from systematic research in this area, to facilitate the simplified and trade friendly registration procedures with quality assurance of the products, there is an increasing need of regulatory authority and national norms in India.

[Study on botanical pesticides and its application in production of traditional Chinese medicine].

The issues including excessive pesticide residues and heavy metal contamination have become the bottle-neck in the development of Chinese herbal medicines. Compared with traditional chemical pesticides, biological pesticides, especially botanical pesticides, are more safe and environment-friendly, which were beneficial to the quality improvement Chinese medicinal materials. Though there exists a weak basic research and it is hard for promotion and regulation, the policy of good and the desire for botanical pesticides will accelerate its development, and replace traditional chemical pesticides gradually. This paper reviews the current situation of botanical pesticides, and gives some pertinence suggestions according to the existing problems and challenges. Research on botanical pesticides will become the key point to solve the problem of excessive pesticides residues and heavy metal contamination, and promote the healthy development of Chinese materia medica.

Study on botanical pesticides and its application in production of traditional Chinese medicine / 中国中药杂志

The issues including excessive pesticide residues and heavy metal contamination have become the bottle-neck in the development of Chinese herbal medicines. Compared with traditional chemical pesticides, biological pesticides, especially botanical pesticides, are more safe and environment-friendly, which were beneficial to the quality improvement Chinese medicinal materials. Though there exists a weak basic research and it is hard for promotion and regulation, the policy of good and the desire for botanical pesticides will accelerate its development, and replace traditional chemical pesticides gradually. This paper reviews the current situation of botanical pesticides, and gives some pertinence suggestions according to the existing problems and challenges. Research on botanical pesticides will become the key point to solve the problem of excessive pesticides residues and heavy metal contamination, and promote the healthy development of Chinese materia medica.