Search Results (80)

Slugs are significant agricultural pests, causing extensive crop damage and economic losses. While chemical molluscicides are commonly used for control, concerns about their environmental impact have driven interest in alternative methods, including beer traps. This study evaluated the effectiveness of different beer types as attractants for slug trapping in field conditions over two consecutive years (2022–2023). Five types of beer—Union Lager, Paulaner Weissbier, BrewDog Punk IPA, Guinness Draught, and Chimay Blue—were tested alongside ethanol (10%) and a control treatment. The results demonstrated that Paulaner Weissbier and Union Lager were the most effective attractants, followed by Guinness Draught and Chimay Blue, while BrewDog Punk IPA had moderate effectiveness. Ethanol (10%) and the control treatment failed to attract slugs, confirming that volatile compounds, rather than alcohol alone, drive slug attraction. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that Paulaner Weissbier contained high levels of isoamyl acetate and limonene, while Union Lager exhibited elevated ethyl esters, which likely contributed to their effectiveness. Environmental factors influenced slug activity, with higher temperatures correlating with increased slug capture rates, while precipitation had no significant effect. These findings highlight the role of fermentation-derived volatile compounds in slug attraction and suggest that optimizing beer traps based on beer composition and environmental conditions could improve their effectiveness as a non-chemical slug control method. Future research should explore the long-term stability of beer attractants, the potential of synthetic formulations, and alternative yeast-based attractants to enhance slug management strategies. Full article

Background/objectives: Schistosomiasis is caused by flatworms of the genus Schistosoma, for which mollusks of the genus Biomphalaria are intermediate hosts. Niclosamide (NCL) is a molluscicide recommended by the World Health Organization (WHO) for control of Biomphalaria. Although effective, it is expensive and environmentally toxic, which raises concerns regarding its widespread use. As a result, we explored new synthetic substances as alternative strategies for controlling Biomphalaria glabrata. We evaluated the molluscicidal activity of 2-(1H-py-razol-1-yl)-1,3,4-thiadiazole and 2-(4,5-dihydro-1H-pyrazol-1-yl)-1,3,4-thiadiazole derivatives against B. glabrata snails and embryos, as well as Schistosoma cercariae (infective larvae). Methods: Adult and young snails were added to 24-well plates containing 20 synthetic compounds from the PDAN series for initial screening over 96 h at a concentration of 100 ppm. Water and NCL (2 ppm) were used as the negative and positive controls, respectively. Active compounds in the adult B. glabrata assay were selected for the tests vs. embryos and cercariae. Results: In the initial screen, only PDAN 52 (63 ± 4%) and 79 (12 ± 3%) showed molluscicidal activity at a concentration of 100 ppm up to 48 h. Consequently, we selected only PDAN 52. The LC₅₀ value found in the tests on embryos after 24 h of treatment was 20 ± 2 ppm and, after 48 h, it was 4 ± 0.5 ppm. Against cercariae, we measured an LC₅₀ value of 68 ± 5 ppm after 4 h of treatment. PDAN 52 did not induce marked toxicity against a second mollusk, Physella acuta, after 48 h of exposure. Conclusions: We highlight the promising molluscicidal activity of PDAN 52 against different developmental stages of the mollusk, B. glabrata, as well the infective larvae of Schistosoma mansoni. Full article

Apple snails (Pomacea canaliculata), one of the 100 most serious invasive species in the world, have invaded mangrove wetlands due to their salinity tolerance. We firstly prepared a plant molluscicide against apple snails based on the mangrove Aegiceras corniculatum in coastal wetland. The effects of four mangrove extracts from A. corniculatum, including ethanol extract (EE), petroleum ether extract (PEE), ethyl acetate extract (EAE), and n-butanol extract (BE), were studied for molluscicidal activity against apple snails in a saline environment. The LC₅₀ values at 48 h of EE, PEE, EAE, and BE were 25 mg/L, 123 mg/L, 170 mg/L, and 14 mg/L, respectively. BE had the highest molluscicidal value (96.7%) against apple snails at 48 h. At 48 h, BE of A. corniculatum leaves significantly decreased the soluble sugar content, soluble protein content, acetylcholinesterase, and glutathione of apple snails to 4.25 mg/g, 29.50 mg/g, 947.1 U/gprot, and 6.22 U/gprot, respectively, compared to those in the control. The increased BE concentration significantly enhanced the malondialdehyde and aspartate aminotransferase contents to 4.18 mmol/gprot and 18.9 U/gprot at 48 h. Furthermore, the damage in the hepatopancreas tissue of apple snails increased, and the cellular structure became necrotic as the concentration of BE from A. corniculatum increased. The content of palmitic acid in BE of A. corniculatum leaves was the highest (10.9%), possibly be a toxic ingredient against apple snails. The n-butanol extract of A. corniculatum leaves showed a potential to control apple snails in the brackish water, and its plantation was beneficial to control the further spread of apple snails in mangrove wetlands. Full article

Fungi play vital roles in ecosystems through parasitism, commensalism, and mutualism. Additionally, they are widely used in industry as bioactive compound producers and biological control agents. Biomphalaria glabrata is a freshwater snail often controlled with chemical molluscicides. However, developing effective alternatives to these chemical treatments is essential. This study evaluated the molluscicidal potential of culture supernatant from Hypocreales fungi isolated from a cave in the Brazilian Cerrado against the B. glabrata. The isolates were identified based on morphological features and ITS rDNA sequences. Fifteen filtrates of Hypocreales fungi were obtained and tested both pure and in different dilutions (10% and 50%) against newly hatched snails during 96 h of exposure. The fungal isolates were identified as belonging to the genera of Clonostachys (1), Cylindrocladiella (1), Fusarium (1), Gliocladiopsis (1), Keithomyces (1), Marquandomyces (1), Ovicillium (1), Pochonia (1), Purpureocillium (1), Sarcopodium (1), Sarocladium (1), Trichoderma (3), and Volutella (1). The results showed 93.33% (14) of the fungal filtrates induced significant mortality, indicating their molluscicidal activity, with Pochonia chlamydosporia FCCUFG 100 and Volutella aeria FCCUFG 107 causing 100% mortality in all dilutions. These results reveal the potential of Hypocreales fungi from a Brazilian Cerrado cave as a promising approach for snail control. Full article

Terrestrial slugs and snails can significantly harm agriculture. Due to environmental concerns associated with chemical molluscicides, biological control methods are increasingly being explored. Oscheius myriophilus (Poinar, 1986), a nematode species recently discovered in association with Arion vulgaris Moquin-Tandon, 1855, holds promise as a biocontrol agent for gastropod pests. In this study, we investigated the chemotactic response and motility of O. myriophilus when exposed to the mucus of five mollusk species: Helix pomatia Linnaeus, 1758, Cernuella virgata (Da Costa, 1778), Deroceras reticulatum Müller, 1774, A. vulgaris, and Tandonia budapestensis Hazay, 1880. Our experiments were conducted at two temperatures (20 °C and 25 °C) to assess how environmental conditions influence nematode behavior. The results demonstrated that the chemoattractiveness of mollusk mucus to O. myriophilus was significantly influenced by both the species of mollusk and the temperature. Overall, nematode motility was higher at 20 °C than at 25 °C, indicating that lower temperatures may enhance the activity of O. myriophilus. Among the tested mollusk species, C. virgata mucus consistently attracted the highest number of nematodes, especially at the lower temperature. Our findings indicate that the chemotactic response of O. myriophilus to mollusk mucus may have potential for the targeted biocontrol of pest mollusks. While C. virgata demonstrated strong attractant potential at the tested temperatures, particularly under cooler conditions (20 °C), further research is needed to confirm whether this represents a consistent temperature-related effect. Future studies should aim to identify the specific chemical cues in mollusk mucus that trigger nematode attraction and examine how these signals interact with a broader range of environmental variables, including temperature, to influence nematode behavior. Full article

Marine cyanobacteria represent a promising yet underexplored source of novel natural products with potent biological activities. Historically, the focus has been on isolating cytotoxic compounds from marine cyanobacteria, but a substantial number of these photosynthetic microorganisms also produce diverse specialized molecules with significant anti-infective properties. Given the global pressing need for new anti-infective lead compounds, this review provides a concise yet comprehensive overview of the current knowledge on anti-infective secondary metabolites derived from marine cyanobacteria. A majority of these molecules were isolated from free-living filamentous cyanobacteria, while several examples were derived from marine cyanobacterial symbionts. In addition, SAR studies and potent synthetic analogs based on selected molecules will be featured. With more than 200 molecules, this review presents their antibacterial, antifungal, antiviral, antiprotozoal, and molluscicidal activities, with the chemical and biological information covered in the literature up to September 2024. Full article

WHO promotes the implementation of a comprehensive strategy to control and eliminate schistosomiasis through preventive chemotherapy, snail control, clean water supply, improved sanitation, behaviour change interventions, and environmental management. The transmission of schistosomiasis involves infected definitive hosts (humans or animals) excreting eggs that hatch (miracidia), which infect freshwater snail vectors (also referred to as intermediate snail hosts) living in marshlands, ponds, lakes, rivers, or irrigation canals. Infective larvae (cercariae) develop within the snail, which, when released, may infect humans and/or animals in contact with the water. Snail control aims to interrupt the transmission cycle of the disease by removing the vector snails and, by so doing, indirectly improves the impact of the preventive chemotherapy by reducing reinfection. Snail control was, for many years, the only strategy for the prevention of schistosomiasis before preventive chemotherapy became the primary intervention. Snails can be controlled through various methods: environmental control, biological control, and chemical control. The chemical control of snails has proven to be the most effective method to interrupt the transmission of schistosomiasis. The current review aims to describe the vector snails of human schistosomiasis, present the chemicals and strategies for the control of snails, the challenges with the implementation, and the future needs. Snail control can play a key role in reducing schistosomiasis transmission and, thus, complements other interventions for disease control. There is a need to develop new molluscicide products or new formulations and methods of applications for existing molluscicides that would target snail vectors more specifically. 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

The Asian clam Corbicula fluminea is a native aquatic species in Eastern Asia and Africa but has become one of the ecologically and economically harmful invasive species in aquatic ecosystems in Europe, North America, and South America. Due to their natural characteristics as a hermaphroditic species with a high fecundity and dispersal capacity, Asian clams are extremely difficult to eradicate once they have infiltrated a waterbody. This is an emerging issue for states in the Northeastern United States, as Asian clams expand their range farther North due to climate change. There has been extensive research conducted to develop chemical treatments for reactively controlling invasive mollusc populations and proactively preventing their further spread. However, treatments are mostly targeted toward biofouling bivalves in industrial settings. A comprehensive review of Asian clam chemical treatments used in natural open-water systems was performed to evaluate molluscicides and identify the toxicity ranges of emerging treatments that maximize Asian clam mortality and minimize the negative impact on water quality and non-target species. The potential chemical applications in Asian clam control and management are summarized in this report to assist resource managers and practitioners in invasive Asian clam management. Full article

Pomacea canaliculata, as an invasive exotic species in Asia, can adversely affect crop yields, eco-environment, and human health. Application of molluscicides containing metaldehyde is one effective method for controlling P. canaliculata. In order to investigate the effects of metaldehyde on adult snails, we conducted acute toxicological experiments to investigate the changes in enzyme activities and histopathology after 24 h and 48 h of metaldehyde action. The results showed that the median lethal concentrations (LC) of metaldehyde on P. canaliculata were 3.792, 2.195, 1.833, and 1.706 mg/L at exposure times of 24, 48, 72, and 96 h, respectively. Treatment and time significantly affected acetylcholinesterase (AChE), glutathione S-transferase (GST), and total antioxidant capacity (TAC) activity, with sex significantly affecting AChE, GST, and TAC activity and time significantly affecting carboxylesterase (CarE). In addition, the interaction of treatment and time significantly affected the activity of GST, CarE and TAC. In addition, histopathological changes occurred in the digestive glands, gills and gastropods of apple snail exposed to metaldehyde. Histological examination of the digestive glands included atrophy of the digestive cells, widening of the hemolymph gap, and an increase in basophils. In treated snails, the hemolymph gap in the gills was widely dilated, the columnar cells were disorganized or even necrotic, and the columnar muscle cells in the ventral foot were loosely arranged and the muscle fibers reduced. The findings of this study can provide some references for controlling the toxicity mechanism of invasive species. Full article

Pomacea canaliculata, the invasive snail, is a host of the parasitic nematode Angiostrongylus cantonensis, which has adverse effects on the agriculture system and human health. This work evaluated the molluscicidal activity of petroleum ether extracts (PEEs) from three species of Chimonanthus against the snail P. canaliculate. Pcp (PEE of C. praecox) showed the most effective molluscicide activity. Sixty-one compounds were identified by GC-MS and the main components were terpenoids and fatty acids. The half-lethal concentration (LC₅₀) of Pcp at 24 h (0.27 mg/mL) and 48 h (0.19 mg/mL) was used to evaluate the biochemical alterations in snail tissue. These sublethal concentrations caused the levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity to increase, while acetylcholinesterase (AChE) activity decreased. Also, under LC₅₀ treatment, several histological changes were observed in the hepatopancreas and foot of the snail compared with the control group. Moreover, the toxic test in rice demonstrated that Pcp has low toxicity. These results suggest that Pcp could be developed as an effective molluscicide for P. canaliculata control. Full article

Niclosamide (NIC) is a potent salicylanilide molluscicide/helminthicide commonly utilized for parasite and mollusc control in aquatic environments. Due to its persistent presence in water bodies, there is growing concern regarding its impact on aquatic organisms, yet this remains inadequately elucidated. Consequently, this study aims to assess the hepatotoxic effects and detoxification capacity of black carp (Mylopharyngodon piceus) in a semi-static system, employing various parameters for analysis. NIC was applied to juvenile black carp at three different concentrations (0, 10 and 50 μg/L) for 28 days in an environmentally realistic manner. Exposure to 50 μg/L NIC resulted in an increase in hepatic lysozyme (LYZ), alkaline phosphatase (ALP), and complement 4 (C4) levels while simultaneously causing a decrease in peroxidase (POD) activity. Additionally, NIC exposure exhibited a dose-dependent effect on elevating serum levels of LYZ, ALP, complement 3 (C3), C4, and immunoglobulin T (IgT). Notably, the mRNA levels of immune-related genes tnfα, il8, and il6, as well as nramp and leap2, were upregulated in fish exposed to NIC. RNA-Seq analysis identified 219 differentially expressed genes (DEGs) in M. piceus after NIC exposure, with 94 upregulated and 125 downregulated genes. KEGG and GO analyses showed enrichment in drug metabolism pathways and activities related to oxidoreductase, lip oprotein particles, and cholesterol transport at 50 μg/L NIC. Additionally, numerous genes associated with lipid metabolism, oxidative stress, and innate immunity were upregulated in NIC-exposed M. piceus. Taken together, these findings indicate that NIC has the potential to cause hepatotoxicity and immunotoxicity in M. piceus. This research offers important insights for further understanding the impact of molluscicide/helminthicide aquatic toxicity in ecosystems. Full article

Schistosomiasis is a neglected tropical disease caused by parasitic worms of the genus Schistosoma. In Brazil, there are reports of infection by the Schistosoma mansoni species, which has the Biomphalaria glabrata snail as one of its intermediate hosts. The present work aimed to test the effects of different Abelmoschus esculentus seed extracts and fractions on adults and embryos of B. glabrata and S. mansoni cercariae. A total of four crude extracts and thirteen fractions with different organic solvents were used for the bioassays. The extracts were analyzed using high-performance liquid chromatography coupled to mass spectrometry. Molluscicidal activity was assessed in 24-well plates, after which the LC₅₀ and LC₉₀ were calculated. Assays with B. glabrata embryos and S. mansoni cercariae were also performed. These findings indicate the presence of flavanoids in the hexane, ethyl acetate, and ethanol crude extracts. For the molluscicidal activity assays, eight fractions had an LC₉₀ value less than that recommended by the WHO. The methanol fraction of the dichloromethane extract (FrMeOH EDM) had the most promising results, with an LC90 of 37.15 mg/L and 100% mortality in embryos of B. glabrata and cercariae. FrMeOH, EDM, and other fractions are possible candidates for new drugs for the combat of schistosomiasis. Full article

Niclosamide (NIC, 2′,5-dichloro-4′-nitrosalicylanilide) is a salicylanilide molluscicide, and the extensive utilization and environmental pollution associated with NIC engender a potential hazard to both human health and the wellbeing of aquatic organisms. However, the mechanism of the chronic toxicity of NIC at environmentally relevant concentrations in terms of oxidative stress, metabolic disorder, and barrier functions in black carp (Mylopharyngodon piceus) is unknown. Therefore, healthy juvenile black carp (M. piceus) (average weight: 38.2 ± 2.5 g) were exposed to NIC at an environmentally realistic concentration (0, 10, and 50 μg/L) for 28 days. The findings of this study indicate that exposure to NIC resulted in reductions in weight gain, decreased activity of antioxidant enzymes, and increased expression of the Nrf2 gene. Furthermore, the liver demonstrated a greater accumulation of NIC than that in the gut and gills, as determined with a chemical analysis. Additionally, NIC exposure led to a significant reduction in ATP content and the activity of Na⁺/K⁺-ATPase and Ca²⁺/Mg²⁺-ATPase in the gut. Meanwhile, exposure to NIC resulted in a decrease in the liver glucose (Glu) level, gut cholesterol (CHO), and glycogen (Gln) and triglyceride (TG) content in all examined tissues. Conversely, it led to an increase in tissue lactic acid (LA) and acetyl-CoA levels, as well as LDH activity. Furthermore, NIC exposure at environmentally relevant concentrations demonstrated an upregulation in the expression of genes associated with glycolysis, such as PK and GK, while concurrently downregulating the gluconeogenesis gene G6Pase. Additionally, NIC exhibited an upregulation in the expression of genes related to β-oxidation, such as CPT1 and ACOX, while downregulating genes involved in triglyceride synthesis, including SREBP1, GPAT, FAS, and ACC1. Moreover, NIC facilitated fatty acid transportation through the overexpression of FATP and Fat/cd36. These results suggest that chronic exposure to NIC is associated with oxidative stress, compromised barrier function, and metabolic disorder. Moreover, these results underscore the significance of assessing the potential consequences of NIC for black carp and aquatic environments for aquaculture. Full article

Limnoperna fortunei, the golden mussel, is a bivalve mollusk considered an invader in South America. This species is responsible for ecological and economic damages due to its voluminous fouling capability. Chemical biocides such as MXD-100™ and sodium dichloroisocyanurate (NaDCC) are often used to control L. fortunei infestations in hydraulic systems. Thus, we proposed to investigate the effects of different periods (24, 48 and 72 h) of exposure to MXD-100™ (0.56 mg L⁻¹) and NaDCC (1.5 mg L⁻¹) on the gills of L. fortunei through morphological and molecular analyses. NaDCC promoted progressive morphological changes during the analyzed periods and only an upregulation of SOD and HSP70 expression during the first 24 h of exposure. MXD-100™ led to severe morphological changes from the first period of exposure, in addition to an upregulation of SOD, CAT, HSP70 and CYP expression during the first 24 h. In contrast, MXD-100™ led to a downregulation of CAT transcription between 24 and 48 h. In static conditions, NaDCC causes lethal damage after 72 h of exposure, and that exposure needs to be continuous to achieve the control of the species. Meanwhile, the MXD-100™ treatment presented several effects during the first 24 h, showing acute toxicity in a shorter period of time. Full article