الفهرس 
Survey of land snailsOnly 14 pages are availabe for public view
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Abstract
Land snails cause heavy damage was manifested in chewing soft vegetative growth, flowers and fruits, beside eating seeds, roots and tubers after sowing or during repining. In addition, the movement of snails causes an undesirable smell which prevents men and even animals from feeding on these contaminated plants. Furthermore, some gastropods work as intermediate hosts for many parasitic worms infesting man and his domestic Animals.
Land snails controlled with different methods (culture, mechanical, legislative, biological, and chemical control). In this study focused on chemical control with used certain pesticides by different methods of applications to recognized on more toxic pesticides, and best method of applications.The results of these studies could be summarized in the following points:
5.1. Survey of land snails in three sites in Assuit Governorate.
The terrestrial snails were surveyed in Assuit Governorate on March 2013 to February 2014 where five species of land snails were recorded in three different locations. five land snail species as Monacha obstructa, Eobania vermiculata, Pupoides coenopictus, Oxyloma elegans and Succinea putris were found in the experimental farm of the faculty of Agriculture Assuit University, in the second area of study (farms in Assuit Governorate next to El Azhar Car-park) one land snail specie was recorded as Monacha obstructa, in the third area of study (El-Wasta village) two land snail species were recorded as Monacha obstructa and Oxyloma elegans.
5.2. Bioassay of certain pesticides by different methods of application against land snails Monacha obstructa.
The testing of toxicity of seven pesticides as metaldehyde, abamectin, methomyl, profenofos, copper hydroxyl, chlorfenapyr and imidacloprid by using three different methods against land snails M. obstructa under laboratory conditions. Results indicated that metaldehyde was the most toxic compound where LC50 values were 151, 52 and 60 ppm, respectively, by using methods of dipping lettuce leaves, bran with methylene blue 0.5 and baits of bran with molasses, while imidacloprid was the least toxic compound where LC50 values were 36111, 33792 and 36789, respectively, by using three previous methods. These compounds could be arranged as following: metaldehyde > abamectin > methomyl > profenofos > copper hydroxyl > chlorfenapyr > imidacloprid.
5.3. The comparison between three different methods as DLL (Dipping lettuce leaves), BBMB (Baits of bran with methylene blue) and BBM (Baits of bran with molasses) by using seven pesticides to control land snails M. obstructa under laboratory conditions. Results showed that toxicity of any tested compound was varied according to the method of application and method of Baits of bran with methylene blue was the most effective with all tested pesticides except copper hydroxyl where the method of Dipping lettuce leaves was the most effective following by Baits of bran with methylene blue and Baits of bran with molasses.
5.4. The effect of different concentrations of seven pesticides as metaldehyde, abamectin, methomyl, profenofos, copper hydroxyl, chlorfenapyr and imidacloprid were evaluated by using three different methods as dipping lettuce leaves, baits of bran with methylene blue and baits of bran with molasses after 1, 2 and 3 day from treatment, against land snails, M. obstructa under laboratory conditions. Results indicated that 150, 400, 8000, 32000, 32000, 48000 and 90000 ppm for metaldehyde, abamectin, methomyl, profenofos, copper hydroxyl, chlorfenapyr and imidacloprid, respectively gave the highest mortality percentage compared with the rest of tested concentrations, also, it is noticed that method of Baits of bran with methylene blue was the best method of application for all tested pesticides except copper hydroxyl, where the method of application dipping lettuce leaves gave the highest mortality percentage, also, by increasing exposure period, this leads to increasing the mortality percentage and the significant differences between the method of application, also, it is noticed that the toxicity of tested pesticides differentiate according to method of application.
5.5. Field experiment to test the efficacy of metaldehyde, abamectin, methomyl, profenofos at constant rate 2% for each pesticide by using five methods of application as directive spray, dipping lettuce leaves, bran baits with methylene blue 0.5% by broadcasting , bran baits with methylene blue 0.5% by heap , and bran baits with methylene blue 0.5% on plastic sheet , for controlling the terrestrial snail M. obstructa in the Egyptian clover field at Assuit Governorate next to El Azhar Carpark. This experiment was conducted during March 2015. Results showed that toxicity of any tested compound was varied according to the method of application and by increasing exposure period of snails for pesticide rate this leads to increasing mortality percentage, but it can be noticed that after 14 day from treatment was highest mortality percentages then decreased after then, may be due to degradation of pesticide because of climate conditions. Also, metaldehyde was the highest toxic compounds where the mortality percentages by using methods of directive spray, Dipping lettuce leaves, bran baits with methylene blue, bran baits with methylene blue 0.5% by heap and bran baits with methylene blue 0.5% on plastic sheet after 21 day from treatments were 92.2, 22.51, 94.48, 79.81 and 59.22%, respectively. While profenofos was least toxic compounds the mortality percentages by using five methods of previous after 21 day from treatments were 20.89, 11.07, 28.03, 18.09 and 14.85%, respectively. These compounds could be arranged as following: metaldehyde > methomyl > abamectin > profenofos in all methods of application against the clover land snail, M. obstructa.
5.6. In the same previous experiment, there was comparison of five methods treatment as directive spray, Dipping lettuce leaves, Baits of bran with methylene blue, bran baits with methylene blue 0.5% by heap and bran baits with methylene blue 0.5% on plastic sheet by using four pesticides as metaldehyde, abamectin, methomyl, profenofos at constant rate 2% for each pesticide. Results indicated that when the pesticide has a high toxicity, this leads to increasing significant differences between methods of application. Also, by increasing exposure period of snails for pesticide rate this leads to significant differences between methods of application. Also, method BMBB gave the highest mortality percentage methods at the rest of methods of application where mortality percentage were 94.48, 80.63, 41.17 and 28.03%, respectively, by using previous pesticides, while Dipping lettuce leaves gave least mortality percentage were 22.51, 17.95, 11.69 and 11.07%, respectively, by using previous pesticides, These methods could be arranged as following: bran baits with methylene blue > directive spray > bran baits with methylene blue 0.5% by heap > bran baits with methylene blue 0.5% on plastic sheet > Dipping lettuce leaves.
5.7. Obtained results indicated that the feasibility of using nano silver abamectin composite (AgNPS@Abm) in controlling land snails, at much lower doses than that required for the free abamectin without using any additives such as organic solvent. These results may be extrapolated to suggest that AgNPS@Abm could serve selectively as a potential moullscicide. The toxicity of nano-silver (AgNPS) loaded abamectin 1% EC AgNPS@Abm and bulk abamectin 1.8% EC against land snails, M. obstructa under laboratory conditions, where results showed that AgNPS@Abm was the most toxic compound compared with bulk abamectin,where LC50 values were 17 and 172 ppm and LC90 values were 55 and 558 ppm for AgNPS@Abm and bulk abamectin, respectively. Also, the field experiment showed that AgNPS@Abm 1% EC gave the highest mortality percentage compared with bulk abamectin at constant rate 2% and 4% for each pesticide