Population Dynamics of Abundant Three Terrestrial Snail Species in Horticultural Fields at Beheira and Giza Governorate, Egypt.

<b>Background and Objective:</b> Studying the population dynamic of the invasive terrestrial snails as agricultural pests, is essential for designing pest control program to reduce the economic losses to commercial field crops, vegetables and fruits. The population dynamic had been estimated for the three terrestrial snails <i>Theba pisana </i>(Müller, 1774) (Helicidae), <i>Eobania vermiculata </i>(Müller, 1774) (Helicidae) and <i>Monacha obstructa</i> (Pfeiffer, 1842) (Hygromiidae) on orange, apple and mango trees in horticultural fields in two locations. These locations are Nobaria City, Beheira Governorate and Mansouria Village, Giza Governorate. This study carried out during the two consecutive activity seasons September, 2018/August, 2019 and September, 2019/August, 2020. <b>Materials and Methods:</b> The population dynamic, incidence and infestation level of terrestrial snails had been recorded on economic host plants such as fruit trees and other field crops and vegetables. The correlations between climatic factors and the population density of land snails were interpreted by statistical analysis for the two seasons. <b>Results:</b> The population density of terrestrial snails increased gradually after winter to reach its maximum density during spring, while the lowest density was recorded in August. The incidence and infestation level of terrestrial snails varied according to the host plant, climatic factors and locality. <i>Eobania vermiculata</i> were the dominant land snail species in Beheira, while <i>Monacha obstructa</i> infested the majority of the examined fruit trees in Giza. <b>Conclusion:</b> Determining the activity and inactivity periods of land snails through the two seasons and their population dynamic will assist in designing effective control management program to decrease the number of pest and the economic losses of agricultural products.

Toxicological Impacts of Some Compounds on Massylaea vermiculata (O.F. Müller 1774), (Gastropoda: Helicidae) Under Laboratory Conditions.

<b>Background and Objective:</b> Effect of some compounds such as Plant extracts (Techno oil and Berna Star), natural origin compounds (Top-nine, Repcar and Chitosan 5%) and classical chemical pesticides (methomyl and lambda-cyhalothrin) were studied against the terrestrial snail <i>Massylaea vertmiculata</i> using the bait technique. Material and Methods: LC₅₀ of the each tested compound of natural compounds were estimated after 14 days of treatment, while LC₅₀ of pesticide were evaluated after 72 hrs of treatment. The impact of LC₅₀of each tested compound on some biochemical parameters, total protein content, alkaline phosphatase (ALP) and acid phosphatase (ACP) activity were determined 48 hrs post treatment. <b>Results:</b> The results revealed that the methomyl and lambda-cyhalothrin were the most effective compounds against test land snails, followed by Repcar, Top-nine and Techno oil, while Berna Star and Nema Ultra Chem come in the last rank. The pesticide compound methomyl was the most toxic one against the tested terrestrial snail species, while the Chitosan 5% was the least toxic one. The results showed that all tested compounds caused fluctuated effect whether increasing or decreasing on all the studies parameters such as total protein content, ALP and ACP activity as well. However, the Techno oil and the Berna Star caused sever decreasing on total protein content and ACP, followed by Top-nine, Repcar, Chitosan 5% (Nema Ultra Chem) and plant extracts. <b>Conclusion:</b> The both tested natural compounds and plant extracts recorded satisfying results compared with methomyl and lambda-cyhalothrin effect and that can be used in the pest controlling programs against terrestrial snails to reduce the environmental pollution.

Preliminary Study on Survey and Population Dynamic of the Terrestrial Snail Monacha obstructa (Pfeiffer) (Hygromiidae, Mollusca) at Crop Fields in Fayoum Governorate, Egypt.

<b>Background and Objective:</b> <i>Monacha obstructa</i> has a serious harmful impact as agricultural pest infested field crops, fruits, vegetables and ornamental plants nurseries in multiple Egyptian governorates. The objective of this research was estimating the population dynamic of the terrestrial gastropod species <i>Monacha obstructa</i> (Pfeiffer) (Hygromiidae) on two economic crop fields and its correlation with temperature degree and relative humidity, the level of infestation on other economic crops had been estimated as well. <b>Materials and Methods:</b> This study was conducted in three sites in Fayoum governorate, 1) Forkous village at Tamiya District, 2) Dar Ramadsite including the Experimental farm and research station of the Faculty of Agriculture, Fayoum University, Fayoum District and 3) Feedimeen village at Sannoris District. The distribution and population dynamics of <i>Monacha obstructa</i> were assessed as one of dominant species on two field crops Egyptian clover <i>Trifolium alexandrinum </i>L. and wheat <i>Triticum aestivum</i> L. at Forkous village, Tamiya District and Dar Ramad site, Fayoum District, during two successive seasons 2016/2017 and 2017/2018. <b>Results:</b> Majority of the examined crops in the sites were found with heavy infestation of this species, while the two species <i>Cochlicella acuta</i> (Müller) (Geomitridae) and <i>Massylaea vermiculata </i>(Müller) (Helicidae) recorded in December, 2017 and in January, 2018, respectively, on mango trees in Feedimeen at Sannoris district for only one time. High density of <i>M. obstructa</i> recorded on Egyptian clover more than wheat at Forkous village and Dar Ramad site for the both seasons in this study. <b>Conclusion:</b> Results concluded that <i>Monacha obstructa</i> has a serious harmful impact as agricultural pest infested field crops, fruits, vegetables and ornamental plants nurseries in Forkous village and Dar Ramad site, respectively.