Susceptibility of some date to infestation by Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae)

The susceptibility of some date cultivars namely: (Sewi, Bartamouda, Malakabi, Sakkouti and Gondeila) to infestation with Oryzae philus surinamensis (L.) was studied at 25˚C and 70±5% R.H. Some biological aspects of this pest and loss in date weight were recorded of each variety. Moreover, correlation between fruit weight as well as chemical components and the susceptibility index of the tested cultivars were investigated. Results indicated that the two cultivars Gondeila and Sewi were the least susceptible to infestation with the pest as shown by the longest developmental period, the lowest number of adult emergence and loss in date weight. Also,the least values of susceptibility index of these cultivars were observed. The Sakkouti and Bartamouda cultivars were more susceptible to infestation by O. suriamensis . Average fruit weight (as physical character) is positively correlated with the susceptibility index. While, the chemical components (such as Ash %, Moisture content % and Total sugars) were negatively correlated with the susceptibility index of the tested date cultivars.