Snail control

While the F. macrophylla isobutylamides, especially pellitorine, are active against several species of pest organisms of medical and agricultural importance, their activity must be enhanced before they can be used on a commercial basis. Hopefully, the results of the present work will direct future studies leading to synthetic isobutylamides of sufficient activity to warrant their practical use in insect and snail control. 

CA237 Kloos, H., F. W. Thiongo, ]. H. Ouma, and A. E. Buttersworth. Preliminary evaluation of some wild and cultivated plants for snail control in Machakos CA246 district, Kenya. J Trop Med Hyg 1987 ... 

Cano, A., Perez-Moreno, M.A., Rodrigo, I., Locascio, A., Blanco, M.J., del Barrio, M.G., Portillo, F., Nieto, M.A. 2000. The transcription factor snail controls epithelial-mesenchymal transitions by repressing E-cadherin expression. Nat. Cell Biol. 2, 76-83. 

Acetaldehyde, tetramer Copper acetoarsenite Metaldehyde Methiocarb Pentachlorophenol Phosalone Propoxur molluscicide, water snail control Clonitralid... 

Considerable effort has been made in the area of snail control in utilizing slow-release incorporated tri-n-butyl fluoride within elastomeric substrates.Using mostly rubber-type substrates, at least five different formulations are cited in controlling seven species of snails under a variety of conditions. Although all of these are physically entrapped, a variety of shapes and densities are now available to allow quite a range of use in the field. The citations in reference 26 showed complete control under a variety of conditions for periods up to 19 months long. 

The modem era of biochemistry and molecular biology has been shaped not least by the isolation and characterization of individual molecules. Recently, however, more and more polyfunctional macromolecular complexes are being discovered, including nonrandomly codistributed membrane-bound proteins [41], These are made up of several individual proteins, which can assemble spontaneously, possibly in the presence of a lipid membrane or an element of the cytoskeleton [42] which are themselves supramolecular complexes. Some of these complexes, e.g. snail haemocyanin [4o], are merely assembled from a very large number of identical subunits vimses are much larger and more elaborate and we are still some way from understanding the processes controlling the assembly of the wonderfully intricate and beautiful stmctures responsible for the iridescent colours of butterflies and moths [44]. 

Triorganotin compounds have also been used experimentally in controUed-release formulations to control the infective snail vector in the debiHtating tropical disease schistosomiasis (biHiarzia) and to control mosquitoes in stagnant ponds (103). As yet, the large-scale use of such methods has Htfle support in the host third world countries where these problems are most severe. Tributyltin chloride has been used to confer rodent-repeUent properties on wine and cable coatings (104). 

Copper has been employed as a bactericide, moUuscicide, and fungicide for a long time and is of importance in the control of schistosomiasis (see also Antiparasitic AGENTS, ANTHELMINTICS FUNGICIDES, AGRICULTURAL). Addition of copper to lake water acts as an efficient deterrent to transmittal of the disease by eliminating snails that act as hosts for the responsible parasite. Copper is commonly utilized at ca 0.1 mg/L as an algicide. In fresh water, acute toxicosis in fish is unusual if the copper concentration is below 0.025 mg/L (70) (see Poisons, economic). 

Symmetry breaking associated with chiral phenomena is a theme that recurs across the sciences—from the intricacies of the electroweak interaction and nuclear decay [1-3] to the environmentally influenced dimorphic chiral structures of microscopic planktonic foraminifera [4, 5], and the genetically controlled preferential coiling direction seen in the shells of snail populations [6, 7]. 

Copper compounds are used routinely and widely to control freshwater snails that serve as intermediate vectors of schistosomiasis and other diseases that afflict humans (Hasler 1949 NAS 1977 Rowe and Prince 1983 Winger etal. 1984 Al-Sabri etal. 1993). These compounds include copper sulfate, copper pentachlorophenate, copper carbonate, copper-tartaric acid, Paris green (copper arsenite-acetate), copper oxide, copper chloride, copper acetyl acetonate, copper dimethyl dithiocar-bamate, copper ricinoleate, and copper rosinate (Cheng 1979). Also, many species of oyster enemies are controlled by copper sulfate dips. All tested species of marine gastropods, tunicates, echinoderms, and crabs that had been dipped for 5 seconds in a saturated solution of copper sulfate died if held in air for as little as a few seconds to 8 h mussels, however, were resistant (MacKenzie 1961). 

Cuttlefish, Sepia officinalis-, eggs 4 (control), 50, 100, or 200 pg/L for 8 weeks Freshwater snail, Thiara tuberculata Dose-dependent decrease in hatching time and survival no external malformations 51... 

No data are available on the toxicity of copper to avian wildlife. All studies with birds and copper use domestic chickens, ducks, or turkeys (Table 3.6). Copper, however, may indirectly affect avian wildlife by curtailing certain prey species. Winger et al. (1984), for example, show that apple snails (Pomacea paludosa) are not only extremely susceptible to copper (LC50 of 24 to 57 pg/L in 96 h immatures most sensitive), but are the primary food of the snail kite (Rostrhamus sociabilis), an endangered species. The decline of the apple snail in southern Florida coincided with the use of copper-diquat to control hydrilla aquatic weeds (Hydrilla verticillata), with serious implications for the snail kite (Winger et al. 1984). 

Synthetic pyrethroids now account for at least 30% of the world insecticide market and are rapidly replacing other agricultural chemicals for control of insect pests. Fenvalerate is one of the more widely used synthetic pyrethroid insecticides. It is derived from a combination of a-cyano-3-phenoxybenzyl alcohol and a-isopropyl phenylacetate ester. Technical fenvalerate is a mixture of four optical isomers, each occurring in equal amounts but with different efficacies against insect pests. Fenvalerate does not usually persist in the environment for >10 weeks, and it does not accumulate readily in the biosphere. Time for 50% loss (Tb 1/2) in fenvalerate-exposed amphibians, birds, and mammals was 6 to 14 h for reptiles, terrestrial insects, aquatic snails, and fish it was >14 h to <2 days and for various species of crop plants, it was 2 to 28 days. Fenvalerate degradation in water is due primarily to photoactivity, and in soils to microbial activity. Half-time persistence in nonbiological materials is variable, but may range up to 6 days in freshwater, 34 days in seawater, 6 weeks in estuarine sediments, and 9 weeks in soils. 

Spraying of PCP to control populations of water snails in rice fields of Surinam resulted in the death of fish and birds, including snail kites (Rostrhamus sociabilis), certain egrets and herons, and wattled jacanas (Jacana jacana). Levels of PCP in these birds and their food items suggested that PCP-contaminated food probably caused the deaths (Vermeer et al. 1974) (Table 23.5). 

SNAIL KITE, Rostrhamus sociabilis. Found dead in rice fields after spraying to control snails (Pomacea glauca, P. lineata) — the exclusive food of snail kites. Residues in soft parts of snails found dead after spraying were about 37 mg PCP/kg fresh weight... 

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