الفهرس 
Survey of terrestrial molluscs on field and vegetable cropsOnly 14 pages are availabe for public view
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Abstract
In recent years, terrestrial snails are considered one of the most important pests on field and vegetable crops. Therefore, basic information concerning ecology, biology and control of these pests has become a matter of immediate concern. 1. Ecological Studies on Certain Terrestrial Snails Attacking Field and Vegetable Crops at Ghrabia Governorate. Ecological studies are very important to reveal the identity of the terrestrial snails infesting field and vegetable crops at Gharbia governorate and characterize their population throughout determination of occurrence, level of infestation, damage and populating dynamics. Moreover, daily activity and dispersal of the dominant species were studied on Egyptian clover. 1.1. Survey of terrestrial snails infesting certain field and vegetable crops at Gharbia governorate. Results of survey carried out on land molluscs infesting field and vegetable crops in Gharbia Governorate during the period from February to April, in both 2017 and 2018 revealed the occurrence of two land snail species. They were the glassy clover snail Monacha cartusiana (Müller) and the amber snail, Succinea putris Linnaeus. The identified species varied in their incidence and level of infestation according to locality and host plant. M. cartusiana infested all inspected fields of clover, wheat, and lettuce in the nine surveyed localities with low, moderate and high levels of infestation, while broad bean and potato were populated with this species in one and two localities, respectively with low infestation. On the other hand, S. putris was detected on clover and wheat in two localities with low to moderate numbers. 1.2. Damage and signs of infestation caused by M. cartusiana. Irregular small holes with smooth edges were observed on leaves of Egyptian clover. On the other hand , longitudinal stripes parallel to midrib were noticed on leaves of wheat. Infested leaves were covered with mucus trails which considered a clear sign of snail infestation . Moreover , mucus trails were observed on soil surface as another sign of snail infestation. Cabbage and lettuce were markedly attacked by M.cartusiana since they provide snails with suitable microhabitat against extreme in temperature and moisture. Leaves of cabbage were mostly rasped on the lower surface, while the upper surface remained intact undamaged. Finally, small rod-shaped sticky black feces were observed on leaves at feeding sites. 1.3. Daily food consumption of M. cartusiana juveniles on leaves of certain field and vegetable crops under laboratory conditions. Daily food consumption of M. cartusiana juveniles (4mm shell diameter) was estimated on leaves of Egyptian clover, wheat, lettuce and cabbage under laboratory conditions. Damage was assessed as consumed weight (mg) and consumed leaf area (cm2). The highest consumed leaf weight by one juvenile was detected on cabbage (56.45mg) followed by lettuce (32.89mg) and Egyptian clover (12.67mg), while the lowest consumed leaf weight was found on wheat (10.87mg). When damage on the tested plants was measured as leaf area (cm2), it was assured that, the highest leaf area consumed by one juvenile of M. cartusiana during 24 hours was noticed on lettuce (2.27 cm2 ) followed by cabbage (1.70 cm2) and Egyptian clover (1.49cm2 ). The lowest consumed leaf area was observed on wheat (0.88cm2). Generally ,it could be concluded that cabbage was the most preferred host followed by lettuce, Egyptian clover and wheat when damage of M. cartusiana juveniles was assessed as consumed weight. However, lettuce was the most favored host followed by cabbage, Egyptian clover and wheat when damage was measured as consumed leaf area.