Search Results (109)

The spread of invasive pests can exacerbate the threat of pest stress to agricultural production. Screening natural antifeedants from the secondary metabolites of plants may provide efficient alternative control methods for the integrated management of invasive pests. Therefore, in this study, the three phenolic substances were evenly mixed with the artificial diet at mass ratios of 1:200 and 1:40, respectively. The treatment groups were labeled as follows: vanillic acid (Va1: 1:200, Va2: 1:40), sinapic acid (Si1: 1:200, Si2: 1:40), and syringic acid (Sy1: 1:200, Sy2: 1:40). Subsequently, the feed intake, body weight, protein content, and digestive enzyme activity of the S. frugiperda feeding were measured. This research was extended to the pupal and adult stages, focusing on pupation rate, pupal weight, adult emergence rate, and adult longevity. The results showed that the food intake and body weight of the 4th–6th instars of S. frugiperda decreased significantly after feeding on the different ratios of phenolic substances. Although the protein accumulation of the 4th–5th-instar larvae was inhibited, the protein content of the 6th-instar larvae showed significant accumulation, with that of the Va2 and Sy1 treatment groups being 124.84% and 165.07% of that of the control, respectively. At the same time, the trypsin activity of the 4th–6th-instar larvae in different treatment groups significantly increased, while the activities of pepsin and α-amylase fluctuated but overall showed an increasing trend. The interference of vanillic acid, sinapic acid, and syringic acid on the digestion and absorption of the larvae limited the pupation rate but did not have a significant effect on the pupal weight. All three phenolic substances reduced the adult emergence rate, but unlike the sinapic acid and syringic acid treatments, vanillic acid also had a negative impact on adult longevity. These results can provide material reserves for the development of antifeedants for S. frugiperda, and can also provide optimal plans for its ecofriendly prevention and control. Full article

As the global population grows, food security and agricultural productivity face challenges, and insect pests cause significant losses to crops. The effectiveness of traditional chemical pesticides is declining, and eco-friendly pesticides need to be developed. Diterpenoid alkaloids (DAs), natural products of plant origin, have attracted attention due to their low environmental risks. Here we review the classification, structure, insecticidal and anti-feeding activities of diterpenoid alkaloids, as well as the current state of research on these chemicals. Studies have shown that C₁₉- and C₂₀-diterpenoid alkaloids show significant activity against a variety of insects, but there are still limited studies on C₁₈-diterpenoid alkaloids. Therefore, through in-depth research on diterpenoid alkaloids, we have discovered that there are various compounds with high efficiency and specificity in insecticidal and antifeedant activities among C₁₉- and C₂₀-diterpenoid alkaloids, which exhibit high selectivity and efficiency towards target pests. This paper emphasizes the potential of diterpenoid alkaloids as novel biopesticides and highlights the need to combine new technologies to conduct further systematic evaluation and screening of these compounds. This work provides new ideas for the development of environmentally friendly pesticides and contributes to sustainable agricultural practices. Full article

Apigenin and luteolin are products of the phenylpropanoid pathway, where apigenin serves as a substrate for the synthesis of luteolin. Apigenin and luteolin are highly bioactive flavones; therefore, in search of prospective biopesticides, the receptiveness of the polyphagous green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) to apigenin and luteolin was studied. The flavones were applied as 0.1% ethanolic solutions to the host plant leaf surface, and aphid probing and feeding activities were monitored using the Electrical Penetration Graph (EPG) technique. The structural difference between apigenin and luteolin, which was the number of hydroxyl groups in the molecule, had an impact on the activity of these flavones. On apigenin-treated plants, the duration of the first probe was three times as short as on the control and five times as short as on the luteolin-treated plants; the duration of the time to the first ingestion phase within the successful probe was shorter than on the control and luteolin-treated plants; the mean duration of xylem sap ingestion bouts and the proportion of xylem phase in all probing activities were the highest; and the duration of salivation before phloem sap ingestion was the longest. Aphids’ response to luteolin-treated plants was less distinct as compared to apigenin-treated plants. Full article

This study investigated the bioactivity of common ash (Fraxinus excelsior L.) and manna ash (Fraxinus ornus L.) leaf extracts, both in the crude form and incorporated into a biopolymer matrix, against spongy moth (Lymantria dispar L.) larvae. Chemical analysis revealed that both species were abundant in polyphenolic compounds, with common ash containing significant quantities of p-hydroxycinnamic acid derivatives and verbascoside, while manna ash was rich in coumarins, particularly aesculetin and aesculin. This study evaluated the feeding deterrent activity, contact and digestive toxicity, effects on larval nutritional indices, and larval development. Chitosan–gelatin-based biopolymer matrices containing the leaf extracts exhibited strong feeding deterrent activity at all tested concentrations, while crude leaf extracts showed moderate deterrence. The biopolymer matrices influenced spongy moth behavior only after digestion, resulting in reduced consumption and growth, as well as a prolonged duration of the third larval instar. No contact toxicity was observed for the biopolymer matrices. Incorporating leaf extracts into the chitosan–gelatin biopolymer matrix significantly enhanced their bioactivity against spongy moth larvae compared with crude leaf extracts. The results suggest that biopolymer matrices containing common ash and manna ash leaf extracts are promising environmentally friendly bioproducts for forest insect control, offering an innovative approach to managing spongy moth populations and protecting forest ecosystems. Full article

The bioactivity of the Ailanthus altissima crude leaf extract (CLE) and a leaf extract incorporated into a biopolymer matrix (BPM) was tested against Lymantria dispar larvae. The crude leaf extracts and those incorporated into a chitosan–gelatin polymer matrix were examined in choice and non-choice assays at 0.01, 0.05, 0.5, and 1% concentrations for feeding deterrent activity, contact, and digestive toxicity. The CLE exhibited moderate deterrent activity at all concentrations, whereas the BPM showed a very strong deterrent effect at 0.5% and 1% and a strong effect at 0.1% and 0.01%. No significant differences in digestive or contact toxicity were observed between the CLE and BPM groups and the control groups. The BPM also influenced larval behavior after digestion, decreasing consumption and growth and increasing development time. The higher bioactivity of the CLE compared to the control group is attributed to its high content of total phenols, flavonoids, and tannins, whereas the enhanced bioactivity of the BPM is due to its incorporation into the biopolymer matrix. Given its very strong deterrent activity, and absence of contact and digestive toxicity, the BPM can be recommended as a potential environmentally friendly bioproduct for forest pest control after field evaluation. Full article

Plant protection against phytophagous pests still largely relies on the application of synthetic insecticides, which can lead to environmental and health risks that are further exacerbated by the development of resistant pest populations. These are the driving forces behind the current trend of research and the development of new ecological insecticides. The mode of action does not have to rely exclusively on acute or chronic toxicity. Another promising approach is the use of plant antifeedants, which can significantly reduce the food intake of phytophagous insects. However, the information on antifeedant substances has not yet been sufficiently evaluated. The aim of this review was to find the most promising plants that provide potent extracts, essential oils (EOs), or isolated compounds with antifeedant properties. The selection was based on a comparison of effective concentrations or doses. Effective extracts were obtained from 85 plant species belonging to 35 families and the EOs came from 38 aromatic plant species from 11 families. Based on the results, Angelica archangelica, Caesalpinia bonduc, Grindelia camporum, Inula auriculata, Lavandula luisieri, Mentha pulegium, Piper hispidinervum, and Vitis vinifera were selected as promising plants with antifeedant potential. These plants are potent antifeedants, and at the same time provide sufficient biomass for industrial use in the development and production of botanical antifeedants. Full article

Endolichenic fungi represent an important ecological group of microorganisms that form associations with photobionts in the lichen thallus. These endofungi that live in and coevolve with lichens are known for synthesizing secondary metabolites with novel structures and diverse chemical skeletons making them an unexplored microbial community of great interest. As part of our search for new phytoprotectants, in this work, we studied the endolichenic fungus Xylaria sp. isolated from the lichen Hypogymnia tubulosa, which grows as an epiphyte on the bark of the endemic Canarian tree Pinus canariensis. From the extract of the liquid fermentation, we isolated two unreported piliformic derivatives, (+)-9-hydroxypiliformic acid (1) and (+)-8-hydroxypiliformic acid (2), along with four previously reported compounds, (+)-piliformic acid (3), hexylaconitic acid A anhydride (4), 2-hydroxyphenylacetic acid (5), and 4-hydroxyphenylacetic acid (6). Their structures were elucidated based on NMR and HRESIMS data. The extract and the isolated compounds were tested for their insect antifeedant (Myzus persicae, Rhopalosiphum padi, and Spodoptera littoralis), antifungal (Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum), nematicidal (Meloidogyne javanica), and phytotoxic effects on mono- and dicotyledonous plant models (Lolium perenne and Lactuca sativa). Compounds 4, 5, and 6 were effective antifeedants against M. persicae and 4 was also active against R. padi. Moreover, 3 and 4 showed antifungal activity against B. cinerea and 4 was the only nematicidal. The extract had a strong phytotoxic effect on L. sativa and L. perenne growth, with compounds 3, 4, and 5 identified as the phytotoxic agents, while at low concentrations compounds 3 and 4 stimulated L. sativa root growth. Full article

The search for natural product-based biopesticides from endophytic fungi is an effective tool to find new solutions. In this study, we studied a pre-selected fungal endophyte, isolate YCC4, from the paleoendemism Persea indica, along with compounds present in the extract and the identification of the insect antifeedant and nematicidal ones. The endophyte YCC4 was identified as Phyllosticta sp. by molecular analysis. The insect antifeedant activity was tested by choice bioassays against Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, and the in vitro and in vivo mortality was tested against the root-knot nematode Meloidogyne javanica. Since the extract was an effective insect antifeedant, a strong nematicidal, and lacked phytotoxicity on tomato plants, a comprehensive chemical study was carried out. Two new metabolites, metguignardic acid (4) and (-)-epi-guignardone I (14), were identified along the known dioxolanones guignardic acid (1), ethyl guignardate (3), guignardianones A (5), C (2), D (7), and E (6), phenguignardic acid methyl ester (8), the meroterpenes guignardone A (9) and B (10), guignarenone B (11) and C (12), (-)-guignardone I (13), and phyllomeroterpenoid B (15). Among these compounds, 1 and 4 were effective antifeedants against S. littoralis and M. persicae, while 2 was only active on the aphid M. persicae. The nematicidal compounds were 4, 7, and 8. This is the first report on the insect antifeedant or nematicidal effects of these dioxolanone-type compounds. Since the insect antifeedant and nematicidal activity of the Phyllosticta sp. extract depend on the presence of dioxolanone components, future fermentation optimizations are needed to promote the biosynthesis of these compounds instead of meroterpenes. Full article

Tribolium castaneum is a challenging pest of stored products, causing significant economic losses. The present study explored the efficacy of Coridothymus capitatus essential oil and its primary constituent, carvacrol, as eco-friendly alternatives for managing this pest. To evaluate their insecticidal potential, repellency, fumigant toxicity, and antifeedant properties, progeny inhibition assays were performed. Carvacrol exhibited superior repellency compared to the essential oil, achieving a 92% repellency rate at 2 mg/cm². Both compounds demonstrated significant fumigant toxicity against T. castaneum, with LC₅₀ values of 168.47 and 106.5 μL/L for the essential oil and carvacrol, respectively, after 24 h. Carvacrol also outperformed the essential oil in antifeedant activity, inducing an 80.7% feeding deterrence at 1.17 mg/g. Moreover, both treatments effectively suppressed the development of the pest’s progeny. These results collectively underscore the potent insecticidal properties of C. capitatus essential oil and carvacrol, particularly carvacrol, as promising candidates for the sustainable management of T. castaneum in stored product protection. Full article

Cestrum parqui L’Herit. (Solanaceae family) is a species of forest shrub, self-incompatible and specialized in pollination, widespread in the subtropical area of the planet, and now widely distributed also in the Mediterranean area. The constituents of its leaves have antimicrobial, anticancer, insecticidal, antifeedant, molluscicidal, and herbicidal properties. The spread of this species represents a valuable source of compounds with high biological value. Various research groups are engaged in defining the chemical composition of the different parts of the plant and in defining its properties in view of important and promising commercial applications. To date, there are only a few incomplete reports on the potential applications of C. parqui extracts as selective natural pesticides and on their potential phytotoxic role. Scientific knowledge and the use of extraction techniques for these components are essential for commercial applications. This article summarizes the research and recent studies available on the botany, phytochemistry, functional properties, and commercial applications of C. parqui. Full article

Plants of the Meliaceae family have long attracted researchers’ interest due to their various insecticidal activities, with triterpenes being the main active ingredients. In this paper, we discuss 93 triterpenoids with insecticidal activity from 37 insecticidal plant species of 15 genera (Munronia, Neobeguea, Pseudocedrela, Nymania, Quivisia, Ruagea, Dysoxylum, Soymida, Lansium, Sandoricum, Walsura, Trichilia, Swietenia, Turraea, and Xylocarpus) in the family Meliaceae. Among these genera, Trichilia deserves further research, with twelve species possessing insecticidal activity. The 93 insecticidal molecules included 27 ring-seco limonoids (comprising 1 ring A-seco group chemical, 1 ring B-seco group chemical, 5 ring D-seco group chemicals, 14 rings A,B-seco group chemicals, 5 rings B,D-seco group chemicals, and 1 rings A,B,D-seco group chemical), 22 ring-intact limonoids (comprising 5 cedrelone-class chemicals, 6 trichilin-class chemicals, 7 havanensin-class chemicals, 2 azadirone-class chemicals, 1 vilasinin-class chemical, and 1 other chemical), 33 2,30-linkage chemicals (comprising 25 mexicanolide-class chemicals and 8 phragmalin-class chemicals), 3 1,n-linkage-group chemicals, 3 onoceranoid-type triterpenoids, 2 apotirucallane-type terpenoids, 2 kokosanolide-type tetranortriterpenoids, and 1 cycloartane triterpene. In particular, 59 molecules showed antifeedant activity, 30 molecules exhibited poisonous effects, and 9 molecules possessed growth regulatory activity. Particularly, khayasin, beddomei lactone, 3β,24,25-trihydroxycycloartane, humilinolides A–E and methyl-2-hydroxy-3β-isobutyroxy-1-oxomeliac-8(30)-enate showed excellent insecticidal activities, which were comparable to that of azadirachtin and thus deserved more attention. Moreover, it was noteworthy that various chemicals (such as 12α-diacetoxywalsuranolide, 11β,12α-diacetoxycedrelone, 1α,7α,12α-triacetoxy-4α-carbomethoxy-11β-hydroxy-14β,15β-epoxyhavanensin, and 11-epi-21-hydroxytoonacilide, etc.) from Turraea showed excellent insecticidal activity. Specially, the insecticidal activity of khayasin from Neobeguea against the coconut leaf beetle were similar to that of rotenone. Therefore, it was a promising candidate insecticide for the control of the coconut leaf beetle. Full article

Furofuran lignans have been identified as the main substances responsible for the biological activities of the plant genus Phryma. Here, four new phrymarolin-type leptolignans A–D (7–10) and eight previously known lignans were isolated from P. leptostachya. Of these, nine exhibited significant antifeedant activity against armyworm (Mythimna separata) through a dual-choice bioassay, with the EC₅₀ values ranging from 0.58 to 10.08 μg/cm². In particular, the newly identified lignan leptolignan A (7) showed strong antifeedant activity, with an EC₅₀ value of 0.58 ± 0.34 μg/cm². Further investigation found that leptolignan A can inhibit the growth and nutritional indicators in the armyworm M. separata. The concentrations of two molting hormones, 20-hydroxyecdysone and ecdysone, were also found to decrease significantly following the treatment of the armyworms with the lignan, implying that the target of the P. leptostachya lignan may be involved in 20-hydroxyecdysone and ecdysone synthesis. These results enrich our knowledge of P. leptostachya metabolite structural diversity, and provide a theoretical basis for the control of armyworm using lignans. Full article

Diterpenes represent one of the most diverse and structurally complex families of natural products. Among the myriad of diterpenoids, grayanane diterpenes are particularly notable. These terpenes are characterized by their unique 5/7/6/5 tetracyclic system and are exclusive to the Ericaceae family of plants. Renowned for their complex structures and broad spectrum of bioactivities, grayanane diterpenes have become a primary focus in extensive phytochemical and pharmacological research. Recent studies, spanning from 2018 to January 2024, have reported a series of new grayanane diterpenes with unprecedented carbon skeletons. These compounds exhibit various biological properties, including analgesic, antifeedant, anti-inflammatory, and inhibition of protein tyrosine phosphatase 1B (PTP1B). This paper delves into the discovery of 193 newly identified grayanoids, representing 15 distinct carbon skeletons within the Ericaceae family. The study of grayanane diterpenes is not only a deep dive into the complexities of natural product chemistry but also an investigation into potential therapeutic applications. Their unique structures and diverse biological actions make them promising candidates for drug discovery and medicinal applications. The review encompasses their occurrence, distribution, structural features, and biological activities, providing invaluable insights for future pharmacological explorations and research. Full article

The pest management of Plutella xylostella, the global pest of cruciferous plants, is primarily dependent upon continued applications of insecticides, which has led to severe insecticide resistance and a series of ecological concerns. The essential oils (EOs) of non-host plants are considered to have a high application potential in pest behavioral control. In P. xylostella, the insecticidal properties, antifeeding activities, and oviposition inhibition effects of many EOs have been studied in larvae and female moths. However, less focus has been placed on the inhibitory effect on sex pheromone communication during courtship, which is vital for the reproduction of the offspring. In this study, by combining electrophysiological studies, laboratory behavioral assays, and field traps, we demonstrated that non-host plant EOs significantly inhibited the reproductive behaviors of both sexes. Notably, the calamus (Acorus gramineus) EO inhibited the preference of male moths for synthetic sex pheromone blends and reduced the egg-laying number of female moths on host plants, with the highest inhibition rates of 72% and 100%, respectively, suggesting a great application prospect of calamus and its EO on the behavioral control strategies of P. xylostella. Full article

Nemertean worms contain toxins that are used to paralyze their prey and to deter potential predators. Hoplonemerteans often contain pyridyl alkaloids like anabaseine that act through nicotinic acetylcholine receptors and crustacean chemoreceptors. The chemical reactivity of anabaseine, the first nemertean alkaloid to be identified, has been exploited to make drug candidates selective for alpha7 subtype nAChRs. GTS-21, a drug candidate based on the anabaseine scaffold, has pro-cognitive and anti-inflammatory actions in animal models. The circumpolar chevron hoplonemertean Amphiporus angulatus contains a multitude of pyridyl compounds with neurotoxic, anti-feeding, and anti-fouling activities. Here, we report the isolation and structural identification of five new compounds, doubling the number of pyridyl alkaloids known to occur in this species. One compound is an isomer of the tobacco alkaloid anatabine, another is a unique dihydroisoquinoline, and three are analogs of the tetrapyridyl nemertelline. The structural characteristics of these ten compounds suggest several possible pathways for their biosynthesis. Full article