Survey, population dynamics and importance value of certain land snail species infesting some vegetable and field crops as well as fruit trees ware determined at some localities in Sharkia Governorate. Results revealed that the glassy clover snail Moncha. cartusiana (Muller) and the amber snail, Succinea. putris (linues) were surveyed at Awlad-Sakr and Abo-Kapeer counties. M. cartusiana snails were found with higher density than S. putris. The majority of the examined crops were found with heavy infestation with M. cartusiana snail while S. putris were recorded with moderate or light infestation in the examined localities. Regarding population dynamics, it found that M. cartusiana snail was recorded with high density at the tested winter crops during spring months (March, April and May) as compared with winter or autumn months. Finally, when importance value was determined, it found that frequency occurrence and population density gave different results. The land snail species can be arranged descedingly,according to its importance values as follow: E. vermiculata>, M. cartusiana >, C. acuta, > H. vestalis. It may be useful to combine frequency of occurrence, population density and biomass in the form of importance value.

Land snails are a destructive agricultural pest in economic crops, but the populations for that pest are highly influenced by temperature and humidity, therefore climatic changes affected their behavior, distribution and population dynamics, for these reasons researchers should follow up on the changes in their behavior, distribution, and population dynamics. In this study, a survey study was conducted to define land snail species existing at Sharkia Governorate, Egypt, from January 2019 to March 2022 in horticultural, vegetable, and field crops and study the population dynamics for the dominant land snail species. Results showed that there are six species of land snails, these species were, Monacha cartusiana, Succinea putris, Eobania vermiculata, Theba pisana, Helicella vestalis, and Cochlicella acuta. The population dynamics of two prevalent land snail species (M. cartusiana and S. putris), were conducted during two successive growing seasons, the Egyptian clover harbored the highest number of M. cartusiana followed by wheat, while the onion was the lowest one during the study period. In the same trends, the land snail S. putris recorded the highest numbers during the growing season of the Egyptian clover crop. Finally, it is concluded that the land snail M. cartusiana considered the first grade of infestation existed everywhere at Sharkia Governorate, and the population density of the land snail is increase gradually after winter till reach the maximum density in spring.