الفهرس 
Ecological Studies on land SnailsOnly 14 pages are availabe for public view
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Abstract
Terrestrial gastropods (snail and slug) species were studied concerning their occurrence survey and population density and influence of temperature, humidity degrees, chemical soil component especially Ca content on their density in 25 localities representing five districts at Kafr EL-Sheikh Governorate, during September 2015 to August 2016. An attempts to obtain basic information concerning their ecology,toxicology, biochemistry and histology on some land snail species. Ten herbivorous species (eight land snails and two land slug species) belonging to three families Helicidae, Succinidae, Limacidae of order Stylomatophora were found on different crops in 25 localities representing five districts at Kafr El-Sheikh Governorate.Population density of Land snails and slug species varied in their incidence and level of infestation according to each locality and host type. There were noticeable irreversible relationship between temperature degrees and population density of terrestrial gastropods as well as relative humidity was an effective essential factor with positive relationship. land snail was found with high density in soil with high Ca content and with low population density in soil with low Ca content.Laboratory and field experiments have been conducted to evaluate the molluscicidal activity of certain biocides compared with Agrinate (24% methomyl, the recommended compound) against the two land snails Theba pisana and Helicella vestalis in Plant Protection Research Institute Sakha branch , Kafr El-Sheikh Governorate during 2016. In the present study different biocides as; Biomajic, Biogard,Biovar, Dipel 2x and Agrinate tested at concentration of 0.5, 1 and 1.5 % as leaf dipping technique against the two investigated land snails . LC50 values were [(1.25, 1. 24,2406.2, 291.2 and 0.82 %) and (1.25, 1.33,19.49, 8.97 and 0.83%)] for T. pisana and H.vestalis respectively . While LC90 values as leaf dipping were [(3.27, 4.14, 6460.2,734.5 and 1.68%) and (3.27, 3.28, 216.8, 37.05 and 2.21%)] for the two land snails,respectively. Laboratory observation indicated that T. pisana was more sensitive to the tested biological insecticides and pesticide Agrinate than H.vestalis . Field results showed that the tested biocides reduced population density of the two land snails with comparable low values of 56 to 85 % after 21 days residue effect. On the other hand,this study revealed that Agrinate was most effective (95 % reduction) to population density.The most effective toxic bio- pesticides on snails Biomajic (Metarizhium anisoplae) and the recommended molluscicide Agrinate 24% methomyl were tested to determined its effective on the activities of the Acetyl choline-esterase (AchE) enzyme of T. pisana and H. vestalis land snails. The snails were investigated after 3, 7,10 and 14 days of exposure in the basis of their 1/4 LC50 and 1/8 LC50 values, the data revealed that Agrinate and Biomajic inhibit the enzyme activity compared with control of tested land snails. The exposure of the land snail Theba pisana to sub lethal dose 1/8LC50 of Biomajic (Metarizhium anisoplae) and Agrinate caused varying degrees of histological alteration in the examined organs. The most deleterious effect have been noticed with the tissue are cerebral ganglia, eyes and eye stalk.