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Controlling the snail intermediate host of schistosomiasis is one of the strategies used to reduce disease incidence. In this study screening tests were carried out on the action of dried powder of...

Purpose: Citrus white snail, Helicella candeharica Pfeiffer (Panpulmonata: Helicidae) is one of the most important orchard pests. In this study, the effectiveness of mineral oil was compared with molluscicide baits such as metaldehyde, ferricole (iron phosphate) and a snail-repellent paint in a commercial citrus orchard in northern Iran to reduce access of citrus white snails to citrus trees.Materials and methods: The number of snails on citrus trees was monitored and counted 10 days after the application of the treatments, and at an interval of 6–8 days up to harvest time.Results: In the first study, the mineral oil and repellent paint treatments reduced a number of snails best. In the second study, using metaldehyde and mineral oil barrier, again the mineral oil barrier reduced snails best. The cost of each treatment during one season per hectare was calculated at 55, 153, 124 and 120 $/ha for mineral oil, iron phosphate, snail-repellent paint and metaldehyde, respectively.Conclusions: Mineral o...

A sensitive, rapid and easy analytical method was validated for the determination of quinoid niclosamide (LDS) molluscicide in water, rice and soil using a QuEChERS extraction procedure and ultra-p...

Plant extracts can provide a viable alternative to controlling many crop pests. This study sought to assess the efficacy of vegetable extracts of the unripe fruits of Ilex paraguariensis (yerba mat...

Aiming to find compounds of natural origin that present molluscicide activity, essential oil from leaves of Eugenia uniflora L. (Brazilian cherry tree) was obtained by steam distillation in a Cleve...

The golden apple snail or GAS (Pomacea canaliculata) is an important invasive pest in irrigated rice that feeds on young rice plants. In many countries in SE-Asia, governments have recently decreased their support of training courses for snail management, because farmers are now considered to know how to effectively manage this pest. Although a great number of sustainable control methods is recommended which do not involve the use of pesticides, it is uncertain whether these are taken up by farmers. Probably, the easiest way to control GAS, is the application of synthetic ‘instant kill’ molluscicides, which can have detrimental effects on the environment, non-target species, and health. The aim of this study was to develop ideas for solutions on how to achieve a sustainable management of GAS without or at least a decreased use of molluscicides. In a large-scale approach, we conducted interviews with rice farmers in seven regions across Vietnam and the Philippines, assessing the participation in training courses, knowledge on snail ecology, the methods of controlling and the utilization of the snail, and the farmers’ suggestions on how to improve pest snail control. Only 23% of the farmers had previously received training in GAS management. We found that training neither had positive nor negative effects on the number of sustainable methods applied, molluscicide avoidance, concern about using molluscicides, or on the farmers’ knowledge about GAS. As much as 74% of the respondents applied molluscicides. Contrary to recommendations, farmers applied only few sustainable control methods. All farmers had clear knowledge gaps about GAS, especially in species identification, which can even further the ongoing decline of native mollusks in rice landscapes. We conclude that the decision to phase out information campaigns has been taken to rash, and that trainings in our study regions carried through previously had limited success, and thus need revision. To decrease molluscicide use, and to promote sustainable management on the large scale, we synthesized our results, and we suggest that information for farmers might be provided through media often accessed, such as TV, radio or the internet (e.g. by entertainment − education). We further discuss the potential of community cooperation to achieve sustainability. As there are distinct limitations to these approaches, we have developed the concept of local GAS management and utilization companies (GASMUC) which could take over sustainable control and utilization of GAS, and native mollusk conservation for an entire community.

Pseudomonas spp. strain Bal1 was isolated from Schistosome vector snails Bulinus Truncates. Strain Bal1 was identified as Pseudomonas putida using partial sequence of 16s rRNA. This strain was able to utilize a Bayluscide as a sole source of carbon and nitrogen. The degradation of Bayluscide by Bal1 strain is mediated by pBal1 (110 Kb) plasmid. The loss of the plasmid resulted irreversibly in a derivative strain that was unable to degrade Bayluscide. The transfer of these plasmids from wild-type strain Bal1 to Bal1M derivative restored completely its capability to degrade the molluscicide. It is proposed that pBal1 is a conjugative plasmid and is involved in the Bayluscide degradation. The effect of bacterial degradation upon toxicity was tested, and it was shown that the molluscicidal action of Bayluscide was significantly reduced by bacterial action.

Every month during the year 2010–2011, the 24 to 96 h LC50 values of molluscicide eugenol, in snail attractant pellets (SAP), were determined against a snail Lymnaea acuminata, with concomitant determination of levels of temperature, pH, dissolved oxygen, carbon dioxide, and electrical conductivity in test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values 2.55, 2.68, and 2.91% in SAP containing starch+eugenol and 2.67, 2.54, and 2.85% in SAP containing proline+eugenol during May, June, and July, respectively, were most effective treatments in killing the snails, while SAP containing starch or proline+eugenol were least effective in January when the 24 h LC50 was 10.73% and 7.14% for starch and proline, respectively. There was a significant positive correlation between LC50 of eugenol containing SAP and levels of dissolved O2 and pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2 and temperature of test water in...

This paper describes the development and validation of a new reverse-phase liquid chromatography-electrospray ionisation tandem mass spectrometric method (RP-HPLC-ESI-MS/MS) for the determination of metaldehyde in different kinds of vegetables. Metaldehyde was extracted with 20 ml acetonitrile from 10 g vegetable and followed by dispersive solid-phase extraction (Bondesil-primary secondary amine, PSA). The identification of metaldehyde was established by chromatographic retention times, analyte-specific fragmentation patterns and relative peak area ratios of two precursor/product ion pairs. The limit of detection of this method was 0.01 mg kg(-1) using an injection volume of 5 µl. The repeatability of this method is excellent and the relative standard deviation (RSD) is less than 4%.

Sublethal treatment (20% and 60% of 24 hr LC50) of young snails (Lymnaea acuminata) with the active molluscicidal constituents ferulic acid and umbelliferone from Ferula asafoetida, eugenol from Syzygium aromaticum, and limonene from Carum carvi caused a significant reduction in the fecundity, hatchability, and survival of the snails. Treatment with the constituents also increased the length of time to hatching of snails. Withdrawal of the snails from constituent treatments after 96 hr with movement to fresh water enabled a significant reproductive recovery in the snail. A 24 hr sublethal treatment with the ferulic acid, umbelliferone, eugenol, and limonene caused a significant (p < 0.05) reduction in protein, amino acid, DNA, and RNA levels in the ovotestis of treated snails.

The molluscicidal activity of powdered nutmeg and mace (Myristica fragrans Houtt.) against the vector snail Lymnaea acuminata was evaluated. The toxicity of both the spices was time- and dose-dependent. The toxicity of mace powder (96 h LC50 = 28.61 mgL−1) was more pronounced than that of nutmeg powder (96 h LC50 = 36.95 mgL−1). Ethanolic extracts of nutmeg and mace were more toxic than their other organic solvent extracts. The ethanolic extract of mace (24 h LC50 = 13.33 mgL−1) was more effective than the ethanolic extract of nutmeg (24 h LC50 = 18.04 mgL−1) in killing the test animals. The 96 h LC50 of column purified fraction of mace was 2.77 mgL−1 whereas that of nutmeg was 3.98 mgL−1. Nutmeg and mace may be used as potent molluscicides.

Preliminary laboratory studies were conducted to determine the molluscicidal potency of Jatropha curcas , the physic nut. Biomphalaria glabrata and Bulinus globosus snails were exposed to varying concentrations of aqueous extracts of crushed J. curcas seeds from unripe, ripe and overripe fruits collected from two geographically different sites, (Bindura and Kariba, Zimbabwe). Snail mortalities were compared between different developmental stages of J. curcas and between seed collection areas, and LC 50 and LC 90 values for the different extracts tested were computed. Biomphalaria glabrata was most susceptible to unripe fruit seed extract (with LC 50 values of 282 and 389 mg l –1 being recorded for Kariba-origin and Bindura-origin plants, respectively) and least susceptible to ripe fruit seed extracts (with LCM 50 values of 605 and 708 mg l –1 being recorded for Karibaorigin and Bindura-origin plants, respectively). Bulinus globosus was most susceptible to overripe fruit seed extract (Kariba-origin plants: LC 50 , 389 mg l –1 ) and least susceptible to unripe fruit seed extract (Kariba-origin plants: LC 50 , 687 mg l –1 ). The area from which fruits were collected did not influence the potency of J. curcas . The potency of J. curcas depends on both the developmental stage of the fruit and the species of the target snail. In view of its many other uses, besides as a molluscicide, we recommend further studies on J. curcas . Keywords: Biomphalaria glabrata ; Bulinus globosus ; intermediate host species; toxicity; Zimbabwe African Journal of Aquatic Science 2008, 33(3): 269–273

Latex extract of the medicinal euphorbious plants, Jatropha gossypifolia, Euphorbia pulcherima, and Croton tiglium were tested as molluscicides in natural ponds against the freshwater snail Lymnaea acuminata. The molluscicidal activity of latex extracts of all the three plants was time and dose dependent at all the exposure periods. A significant negative correlation between LC values of latex extracts and exposure periods existed, thus LC50 values decreased from 17.32 mg/L (24 h) to 5.66 mg/L (96 h) in case of Jatropha gossypifolia, 3.79 mg/L (24 h) to 1.56 mg/L (96 h) in case of Euphorbia pulcherima and 12.32 mg/L (24 h) to 4.85 mg/L (96 h) in case of Croton tiglium against Lymnaea acuminata. The latex of all the three euphorbiales may probably be used as potent eco-friendly molluscicides in natural ponds for managing the harmful snail population.

Some new heterocyclic nitrogen compounds 1-14 have been synthesized from cyclization of 5-styryl-3-mercapto-6-methyl-1,2,4-triazines 1 with active methylene and/or nitrogen compounds and were evaluated as molluscicidal agents. Significant molluscicidal activities for some of the products towards Biomophalaria Alexandrina snails were observed.

Essential oils from Pinus halepensis, P. brutia, P. pinaster, P. pinea and Cedrus atlantica were chemically analyzed by gas chromatographic and gas chromatographic mass-spectra, and tested for molluscicidal activity against Bulinus truncatus. The oil from C. atlantica was found the most active (LC 50 = 0.47 ppm). Among their main constituents, a-pinene, s-pinene and myrcene exhibited potent molluscicidal activity (LC 50 = 0.49; 0.54 and 0.56 ppm, respectively). These findings have important application of natural products in combating schistosomiasis.

Overall, 173 tropical plants from 72 different families, collected from the north-western and western regions of Puerto Rico, were screened for their molluscicidal properties against Biomphalaria glabrata, the intermediate host of Schistosoma mansoni. Six plant extracts were effective at 50 ppm. The two most effective extracts were those from the leaves of Didymopanax morototoni (Araliaceae) and Mammea americana (Guttiferae), which, at 50 ppm, killed all snails after 24 h of exposure and a day for recovery. Under the same conditions, extracts of Furcraea tuberosa, Argemone mexicana and Paullinia pinnata killed 50% of the snails and that of Solanum americanum killed 33%. The most effective extracts (or their active components or compounds based on them) may have potential as molluscides for the relatively cheap control of human schistosomiasis.

The extracts of plant species including Sapindus trifoliatus, Acacia concinna, Madhuca indica and Phytolacca acinosa were evaluated for their molluscicidal properties against the freshwater snail Lymnaea luteola, a vector of animal schistosomiasis. The methanol extracts of the seeds were tested against adults and the results showed S. trifoliatus as the most toxic, followed by M. indica, P. acinosa and A. concinna. Hence, the N-butanol extract of S. trifoliatus was tested against both adults as well as eggs of L. luteola. The results indicated that the N-butanol extract was more toxic than the methanol extract and the eggs were more susceptible than adults.

Laboratory experiments were done to test the efficacy of a number of pesticides against the eggs of the field slug, Deroceras reticulatum (Muller). Research was based on paper-contact toxicity tests in which the eggs were continuously exposed to the compounds and the mortality rate assessed each day. The compounds tested included molluscicides (metaldehyde and methiocarb), herbicides (ioxynil, bromoxynil, pyridate), insecticides (thiocyclam hydrogen oxalate, imidacloprid, diflubenzuron, teflubenzuron, azadirachtin), and other compounds such as saponin, carvone and Pongamia pinnata (L.) extract. The herbicides ionynil and bromoxinyl, and the active ingredient of neem ( Azadirachta indica A. Juss) oil, azadirachtin, killed all the eggs of D. reticulatum at doses

Molluscicidal activity of leaves, bark, and seed of custard apple (Annona squamosa L.) against the snail Lymnaea acuminata was studied. Highest molluscicidal activity of the plant was observed in seed extracts. Acetogenins extracted from the seed of the plant were more toxic than synthetic pesticides. Combinations of equal parts custard apple seed powder with oil from cedar, Cedrus deodara Roxh., and from neem, Azctdirachta indica A. Juss., was more toxic than the individual components of these plants.

The present study was undertaken to investigate the influence of biotic (snail size and presence of food during the test) and abiotic factors (temperature, water hardness and concentration of organic materials) on the molluscicidal activity of Euphorbia milii latex. Bioassays were conducted with B. glabrata (10 snails per concentration) and snail lethality was evaluated after 24 hr and 48 hr of exposure to lyophilized latex solutions. Neither the degree of water hardness, nor the presence of food during the test affected latex-induced snail mortality. The snail size had a minor influence on E. milii-induced snail lethality. Newly-hatched (shell diameteror = 1 mm) as well as young (3-8 mm) snails were slightly less susceptible than older (10-25 mm) mollusks. On the other hand, the molluscicidal effect of E. milii latex was modified by environmental factors such as temperature (i.e., LC50 and LC90 values were halved for every 10 degrees C rise in temperature) and concentration of organic materials in the water (i.e. the higher the concentration of organic matter, the higher the LC50 value). The efficacy of E. milii latex as a molluscicide can be modified by factors such as water temperature and concentration of organic materials, and to a lesser extent by snail size.

A total of 86 lipophilic and hydrophilic extracts obtained from 43 samples of cultured and field collected freshwater and terrestrial cyanobacteria have been screened for their biological activities. Anti-microbial evaluation demonstrated 16.3% to be active against Gram-positive and 5.8% against Gram-negative bacteria, while 10.5% possessed antifungal activity. A lethal effect (= 60%) against brine shrimp (Artemia salina Leach) was exhibited by 8.1% of all extracts at 500 ppm. Cytotoxic activity against KB cells was shown by 1.2%, and 8.1% were active against Caco-2 cells at 50 ppm. A molluscicidal effect against Biomphalaria glabrata was found for 5.8% of the extracts (LC 100 < 100 ppm).

Casual observation reveals that the freshwater snail Bulinus globosus (Morelet), never preponderates in habitats that support the plant Polygonum lanigerum Meisn. An investigation on toxicity of aqueous extracts of the leaves and stem of this plant on Bulinus globosus in a 24 h static bioassay demonstrated toxicosis. The 24-h LC50 for the leaf and stem extracts were 29.9 and 35.8 mg/liter, respectively. The relative potency of the extracts from the two plant parts was not significantly different.

The essential oils of cedar (Cedrus deodara Roxh.) and neem tree (Azadirachta indica A. Juss.), powder from bulbs of garlic (Allium sativum Linn.), and the oleoresin extracted from rhizomes of ginger (Zingiber officinale Rose.) were mixed in different combinations to test the collective toxicity against the snail Lymnaea (Radix) acuminata Lamark. A mixture of cedar and neem oils were most toxic to Lymnaea acuminata of the combinations tested. Combinations of neem oil with ginger oleoresin or garlic bulb powder was more toxic than the individual components.

The adult snails, Indoplanorbis exustus were exposed to the synthetic molluscicide, niclosamide, and the crude – aqueous extract of Brassaia actinophylla at the LC50 concentrations (0.009 mg/ 1 and 23.73 mg/1, respectively) for 24 hours. The results showed relatively similar ultrastructural changes in the digestive system of snails exposed to niclosamide and B. actinophylla. The general cytological alterations that occurred in the epithelia of esophagus, intestine and digestive gland were the formation of blebs, increased fusion of vacuoles, infolding and thickening of basal lamina, formation of myelin-like figures, degranulation and dilation of rough endoplasmic reticulum, swelling of mitochondria and cristae, and an increase in mucus production. Most of these reactions were more severe in snails treated with B. actinophylla than those exposed to niclosamide.

A total of 50 different plant species of 22 families was investigated for molluscicidal activity against Indoplanorbis exustus. Twenty-one species (42%) demonstrated molluscicidal activity. The crude water extract of Brassaia actinophylla showed the best result with 24 hr. LC50 and LC90 values of 23.73 and 32.11 mg / l, respectively. The control group of snails exposed to niclosamide showed 24 hr. LC50 and LC90 values of 0.009 and 0.01 mg / l, respectively. The 24 hr. LC50 and LC90 values of the crude water extract of B. actinophylla on two species of fish, namely, Puntius gonionotus and Poecilia reticulata were 47 and 55 mg/1, and 85 and 111 mg/1, respectively. Concerning the crustacea, Moina macrocopa and Macrobrachium rosenbergii, the 24 hr. LC50 and LC90 values of the crude water extract of B. actinophylla were 258 and 861 mg/1, and 141 and 181 mg/1, respectively.

The molluscicidal properties of Solanum nigrum L. were tested against three Egyptian snail species (Biomphalaria alexandrina, Bulinus truncatus and Lymnaea natalensis), each an intermediate host of...

Toxicity bioassays were conducted on embryos and early larvae of quagga mussels, Dreissena bugensis, using a filtered aqueous extract and a lyophilized butanol extract of the soap berry plant Phytolacca dodecandra. Developmental stages exposed to each extract were embryos to trochophores (ca 3h‐17h), trochophores to D‐hinge larvae (ca 17h‐40h) and embryos to D‐hinge (3h‐ca 40). Over the whole embryo to D‐hinge exposure period, the aqueous extract resulted in a lowest observed effective concentration (LOEC) of 5mgl‐1 although mortality did not exceed 50%. For the butanol extract, the LOEC was 2mgl‐1 and the LC50 was 2.1 mgl‐1. For the aqueous extract, most of the endod toxicity was seen at the embryo stage, whereas for the butanol extract the toxicity was associated with the trochophore stage. Compared with other non‐oxidizing commercial molluscicides, endod has only moderate toxicity to early dreissenid life stages.

Molluscicidal activity of Zingiber officinale rhizome extract, fruits of Trachyspermum ammi, seeds of Trigonella foenum-graecum and Allium cepa bulbs were studied against the snails Lymnaea acuminata and Indoplanorbis exustus. Toxic effect of different preparations and chemicals present in them were also studied against both the snails. It was reported that cineole, citral and oleoresin from ginger rhizome and thymol present in fruits of Trachyspermum ammi were potent molluscicides. Toxic effects of the different preparations and their chemical components were time-as well as dose-dependent.

Histopathological changes in the gill of Dreissena polymorpha exposed to a new molluscicide were investigated. Ultrastructural examinations clearly demonstrated severe damage. The dilation of intercellular spaces concomitant with the vacuolation of epithelial cells led to progressive separation of the epithelium from the underlying chitinous rod. As a result, at the extremities of filaments, the chitinous rod remained free of cells. The ultimate change consisted of the complete destruction of gill tissues.

A total of 153 crude extracts of Panamanian plants (28 species from 21 families) have been screened for molluscicidal activity against Biomphalaria glabrata, one of the intermediate hosts of schistosomiasis. When tested at 400 ppm, 15 extracts were active. The most potent of these came from Cyperus luzulae (Cyperaceae) and Hymenaea courbaril (Leguminosae).

Four saponins were isolated from the methanol extract of the pericarps of Guaiacum officinale using a bioassay with the snail Biomphalaria glabrata. Their structures were established as 3-O-(s-D-glucopyranosyluronic acid)-oleanolic acid (1), 3-O-{[a-L-rhamnopyranosyl(1?3)-a-L-rhamnopyranosyl(1?2)]-a-L-arabinopyranosyl (3?1) [-s-D-glucopyranosyl]}-30-norolean-12,20(29)dien-28-oic acid (2, guaianin D), a-D-glucopyranosyl 3-O-[a-L-rhamnopyranosyl (1?3)-s-D-glucopyranosyl(1?3)-a-L-arabinopyranosyl]-30-norolean-12,20-(29) dienoate (3, guaianin B) and s-D-glucopyranosyl 3-O-[a-L-rhamnopyranosyl (1?3)-s-D-glucopyranosyl(1?3)-a-L-arabinopyranosyl]-oleanolate (4, guaianin C). The LC 100 /24h of monodesmosidic saponins 1 and 2 were 2.5 and 10 ppm, respectively, while the bidesmosidic saponins 3 and 4 were inactive at 10 ppm. Basic hydrolysis of 3 and 4 produced the corresponding monodesmosidic saponins 5 (guaianin) and 6 (guaianin H). These saponins were active at 2.5 and 5 ppm, respectively.

Nineteen plant species from fourteen families used in the traditional medicine of North American Indians have been tested for their fungicidal (Cladosporium cucumerinum, Candida albicans), bactericidal (Bacillus subtilis, Escherichia coli), larvicidal (Aedes aegypti) and molluscicidal (Biomphalaria glabrata) activities. Of the species investigated, 9 were active against Cladosporium cucumerinum, 9 against Candida albicans, 12 against Bacillus subtilis, 18 against Escherichia coli, 3 against Aedes aegypti, and 11 against Biomphalaria glabrata.

Experiments were conducted to determine the appropriate size of Aridan, Tetrapleura tetraptera, that could be used for efficient extraction of the molluscicide. The toxicity of the freeze‐dried water extract of the molluscicide was also studied in rodents. The results suggest that the appropriate calculated particle size of 186.5 μm would be the ideal size for massive extraction of the molluscicide for field use. In acute mammalian toxicity tests, acute oral, acute dermal, acute dermal irritation, dermal sensitization and repeated oral toxicity tests, Aridan, proved to be slightly toxic as shown by the haemorrhagic appearance of the lungs of rats, temporary incoordination and increase in respiratory rate in mice and non‐toxic as shown by the normal condition of other organs and the animals.

Successive ether and chloroform extracts of different organs and fatty acids from Canna indica L. demonstrated molluscicidal activity on snails Biomophalairia alexandrina. Root extracts were the most active with LC50 values of 110, 160, and 198 ppm for the ether, chloroform, and fatty acid extracts, respectively. An ether extract of the dry plant contained chlorophyll and an oily material identified by spectral analysis as a steroid containing β-unsaturated, 5-member lactone ring. This new compound, which has provisionally been named cannagenin, had a highly synergistic effect with chlorophyll on the mortality of snails.

Pestoban is a mixture of three plant extracts, only two of which (Cedrus deodara and Azadirachta indica oils) show toxicity against each of the snail species under test. The third (Embelia ribes) is non-toxic, but when all three are mixed, the toxicity of the mixture is 103 time more active than either of the two toxic components.

A range of tests are presented which, if applied systematically, could provide useful data to assist in the formulation of terrestrial molluscicides. Since the majority of molluscicides contain chemicals hazardous to the environment and non‐targeted animals, steps need to be taken to reformulate them in such a way that the levels of toxic active ingredients are reduced.

A homogenate of raw garlic was chemically fractionated and the toxicity of individual fractions against the snails Lymnaea acuminata and Indoplanorbis exustus was compared. Allicin (allyl 2-propenethiosulphinate) was tentatively identified as the active moiety causing snail death by co-migration of the active agent with extracted and synthetic allicin on TLC plates.

The fate of Phytolacca dodecandra (Endod‐S) and Niclosamide in aquatic systems was investigated both under laboratory and field conditions. Endod‐S was observed more soluble in water (12,937.7 mg/1 @ 30°C) than Niclosamide (19.4 mg/1 @ 30°C). The octanol/water partition coefficients (K0W) of Endod‐S and Niclosamide were 0.165 and 5.880×104 respectively. Adsorption isotherm studies indicated that the Freundlich parameters (K, n) for Endod‐S were 1.60×10‐6 and 0.43 respectively for powdered activated carbon (PAC), and 3.69×10‐12 and 0.24 respectively for silt loam soil. Similar parameters for Niclosamide were 0.02 and 4.93 respectively for PAC, and 9.85×10‐5 and 2.81 respectively for the same soil. The adsorption coefficient (Koc) for Endod‐S and Niclosamide was 1.60×10‐6 and 0.02 respectively for PAC, and 1.62×10‐10 and 4.34×10‐3 respectively for silt loam soil. Hydrolysis of both molluscicides occurred in distilled water buffered at pH above 7. No photolysis of Endod‐S and Niclosamide was observe...

Agave Americana and Balanites Aegyptica Were Evaluated For Molluscicidal Properties Against Eggs and Adults Of Three Species Of Freshwater Snails, Lndoplanorbis Exustus, Lymnaea Luteola and Gyrau-Lus Convexiusculus and For Haemolytic Activity With Sheep Red Blood Cells. Further Studies Were Then Performed With Extracts Of The Leaves Of A. Americana and The Fruits Of B. Aegyptica, and A. Americana Was Found To Be More Effective Against All Stages Of Snail Development.

The herbal pesticide Pestoban is a liquid concentrate of some Indian medicinal plants which is also a potent molluscicide. Its toxic effect against the snail L. acuminata is time as well as dose dependent. Its molluscicidal activity is higher than synthetic molluscicides. The dose levels used against the snail are safe for fish.

The two insect growth inhibitors, chlorfluazuron (IKI7899) and flufenoxuron (Cascade) were evaluated for their toxic and biochemical action against the terrestrial snails Helix aspersa (Muller). Chlorfluazuron was found to be more toxic to the snails than flufenoxuron. The experimental snails were fed on lettuce discs treated with low concentration (1%) of each compound for a duration time of 1,2,3 and 5 days. There were no significant differences between treated and untreated snails in total proteins, total lipids and glycogen content except in the case of chlorfluazuron treated snails, the glycogen content was increased. Both compounds reduced the activity of alkaline phosphatase (AIP). Chlorfluazuron decreased the activity of acid phosphatase(AcP) and phenoloxidase (PO) enzymes, while flufenoxuron has an opposite effect. Chlorfluazuron exhibited an increase in the activities of transaminases(GOT and GPT) whereas both enzymes were not affected by the flufenoxuron treatment. These results indica...

In vitro relative sensitivity of NTE of Helix aspersa and Theba pisana snails to eight organophosphorous compounds were investigated. The most potent inhibitors against NTE of H. aspersa snail were O‐methyl O‐2,5‐dichlorophenyl phenylphosphonate and dimethoate‐oxon with Ki values of 6.01 x 105 and 5.94 x 105 M‐1 min‐1, respectively. In the case of T. pisana, triphenyl phosphite and O‐methyl O‐2,5‐dichlorophenyl phenyl‐phosphonate showed high potency as NTE inhibitors with Ki values of 1.74 x 107 and 4.14 x 106 M‐1 min‐1, respectively. From the results obtained, NTE free of inhibitor had the highest dissociation constant in both snails, where Km value of H. aspersa snail was 180 times smaller than Km value of T. pisana. The lowest Km value of H. aspersa snail was found to be 1.6 x 10‐3 M for EPN‐oxon while the highest value was 1.2 x 10‐2 m for leptophos‐oxon. On the other hand, the lowest Km value of T. pisana snail did account for 2.4 x 10‐3 for dimethoateoxon. Finally it could be concluded that...

Water extracts of the bulb of Garlic (Allium sativum L.) have a high molluscicidal activity. It was observed that the molluscicidal activity of extracts of garlic bulb against the snail Lymnaea acuminata (Lamarck) was time as well as dose dependent.

The bran toxic baits (0.5 % w/w) of five oxime carbamate pesticides; aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were tested for their molluscicidal activity against Theba pisana snails under Laboratory conditions. In addition, the in vivo effects of these compounds on seven vital enzymes namely Acetylcholin‐esterase (AchE), glutathion‐S‐transferase (GST), glutamic oxlaoacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), acid phosphatase (AcP), alkaline phosphatase (AIP), and adenosine triphosphatase (ATPase) activities of the snail tissue were also investigated after 1,3, and 5 days of exposure. The results showed that methomyl was the most potent candidate, whereas thiofanox was the least effective one against the snails. LT50’s values of aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were 5.77, 4.69, 2.31, 3.97 and 6.67 days, respectively. Results of the potency of the tested pesticides against AchE activity were in harmony with the toxicity of these compounds to sna...

The latex of four plants belonging to the family Euphorbiaceae viz. Jatropha gossypifolia, Euphorbia royleana, Euphorbia antisyphlitica and Euphorbia lactea cristata caused significant reductions in the acid and alkaline phosphatase activity in nervous tissue of the snail Lymnaea acuminata. The reduction in the activity of both the phosphatases was time and dose dependent; the order of effectiveness was as follows: Euphorbia lactea cristata > Euphorbia antisyphlitica > Euphorbia royleana > Jatropha gossypifolia. It has been suggested that the inhibition of these enzymes might be through activation of Protein Kinase C.

Extracts from Tamarindus indica L. (Leguminosae) fruit pulp were found to have molluscicidal activity against Bulinus truncatus snails. Activity was thought to be due to the presence of saponins.

Controlled release formulations of the molluscicides niclosamide, Bayluscide, trifenmorph and mercaptodimethur have been prepared by incorporation into plates of ethylene‐vinylacetate copolymer (EVA) in order to develop a more environmentally compatible method for controlling Schistosomiasis transmitting water snails. With the exception of mercaptodimethur, all substances were released into water at low rates from most formulations (

The effects of the fungicide Mancozeb, the herbicide Ametryne, and the molluscicide Niclosamide, on the anaerobic digestion of glucose by a mixed bacterial population were evaluated. Effects on activity of a pure culture of the methanogen, Methanosarcina barkeri was also tested. Pronounced inhibition of methanogenesis from glucose was observed for Mancozeb at a concentration of 100 mg.l‐1. In contrast, methanogenesis by Methanosarcina barkeri was not affected by Ametryne and Mancozeb, although Niclosamide delayed the onset of methanogenesis. Long‐term incubations (up to 60 days) indicated relief from Niclosamide inhibition.

Laboratory experiments were conducted to assess the toxic effects of bayluscide and malathion against Schistosoma mansoni miracidia. The results indicate that survival of miracidia varied with times of exposure and concentrations of tested chemicals. Statistical analyses reveal that LC5, LC50 and LC95 for bayluscide were 0.04 ppm, 0.06 ppm and 0.12 ppm after 2 hours of exposure; 0.02 ppm, 0.03 ppm and 0.06 ppm after 4 hours of exposure; and 0.01 ppm, 0.02 ppm and 0.04 ppm after 6 hours of exposure respectively. These data indicate that bayluscide is much more toxic to the first stage larvae of schistosomes than to snail intermediate hosts cited in the literature. Application of lower concentrations of molluscicide in the transmission sites is thus expected to curtail the survival of miracidia; therefore controlling schistosomiasis at relatively low costs. Such applications also reduce the risk of toxicity to non target organisms present in the aquatic environment. Statistical analysis of the results of tests using malathion gave LC5, LC50 and LC95 values of 83.38 ppm, 153.11 ppm and 245.85 ppm after 2 hours of exposure; and 76.86 ppm, 116.48 ppm and 172.04 ppm after 4 hours of exposure respectively. These data indicate that the use of malathion as an insecticide in tropical ecosystems may also affect the survival and viability of schistosome miracidia. Such uses could help reducing the risk of schistosomiasis transmission in these particular locations.

The acute and subchronic toxicity of the mol-luscicidal plant. Ambrosia maritima L., has been tested on rats. No toxic signs could be detected neither after oral administration of 5 g/kg of dried leaves of the plant as a powder or as a methanolic extract, nor after the incorporation of 50, 000 ppm powdered leaves in the feed during 4 weeks.Using an aqueous extract of the plant material of A. maritima or using ambrosin, one of the active molluscicidal components of the plant, no mutagenic activity could be detected in the S. typhimurium strains TA97, TA 98, TA1538, TA100 and TA1535.