Influence of climatic factors on population denisty of land snails infesting some crops and their damage quessina district, Minufeya governorate

This study was conducted under field conditions at Quessna district, Monufya Governorate during two successive seasons 2009 and 2010. The present work aimed to throw light on the effect of climatic factors temperature degree and relative humidity on land snails population and their damage to some stand crops( Clover, Lettuce and Navel orange). The obtained results could be summarized as follows:Monacha cartusiana (Muller) and Eobania vermcculata (Muller) were only observed infesting Clover, Lettuce and Navel orange during the experimental period. Also, the the ecological studies indicated that M. cartusiana was found in abundance on Clover and Lettuce both, meanwhile Navel orange had E. vemiculata more than the another, snail. , Clover was the most attractive to M. cartusiana followed by Lettuce and Navel orange, whereas, the last crop was the most attractive to E. verrnaculata than Clover and Lettuce. , The land snails population was fluctuated during the experimental crop life from month to month due to variations in temperature degree and relative humidity. The results indicate that there is a positive correlation between snail population and the relative humidity , meanwhile it is negative with the temperature degree. The highest population (115.5 individuals) was recorded in February (16 C and 59.9 R.H.) and the lowest one (33 individuals) in May (29 C and 54.7% R.H.). , The obtained results showed that the highest infestation of land snails (0.89%, 0.83% and 0.64%) and the lowest (0.45%, 0.49% and 0.19%) for Clover, Lettuce and Navel orange were recorded in March (18.6C and 59.7% R.H.) and in May (29 C and 54.7% R.H.), respectively , The obtained results proved that the most suitable geographical conditions to increase the population of land snails are low temperature degree and height relative humidity. Also, it is added that, there is a positive correlation between population of land snails and their damage to the three tested crops.