الفهرس 
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Abstract
The saw-toothed grain beetle, Oryzaephilus surinamensis (L.), is an important pest of many stored product foods and a little is known about its growth and behavioral response toward some food hosts. The effect of insect infestation by this insect on nine various food types as standard diet, corn, rice, semi-dry dates, dry dates, white sesame, reddish yellow sesame, chickpea and groundnut was investigated. Insect parameters studied on the tested food types (as regards to resistance) were mean developmental period, number of F1 progeny, growth index and weight loss (%) after one month. The shortest mean complete developmental period was 21.00 days on the standard diet, while the longest one was 29.00 days on reddish yellow sesame seeds. Values of the growth index (GI) ranged between 3.22-4.63% for reddish yellow sesame seeds and the standard diet, respectively. After one month of storage, the wet weight loss (%) ranged from 0.50 to 11.17 % on white and reddish yellow sesame seeds and standard diet, respectively. The relative wet weight loss (%) reached its maximum (43.23%) on the standard diet and the lowest one was 1.94% in white sesame and reddish yellow sesame seeds, respectively after one month of storage. All tested food types were infested with O. surinamensis and no immune food was found free from the insect infestation but the insect preferred some food types than others. The second part of the study determined the susceptibility of six dry date, Phoenix dactylifera (L.) varieties named Malkabi, Skooty, Pertomoda, Shamia, Dekina and Gondella to infestation with the saw-toothed grain beetle under free-choice and non-choice conditions. The tested parameters of evaluation were mean complete developmental period, number of F1 emerged adults, susceptibility index and weight loss % after one and three months of storage. The shortest mean complete developmental period of the insect was 28.33 days on Skooty, while the longest one was 33.67 days on Gondella under free–choice bioassay method. Dekina was the most preferred variety to the insect infestation since their fruits produced the highest progeny number (73.67 adults), whereas Skooty recorded the lowest mean number (25.67 adults). Values of susceptibility index (SI) ranged between 4.38% for Gondella and 6.37% for Dekina. After one month of storage, the percentage of wet weight loss ranged between 1.83 in Pertomoda and 10.83% in Malkabi, while after three months of storage the lowest percentage was 5.83 % in Gondella variety and the highest one (25.67%) was detected in Malkabi variety. The relative wet weight loss (%) reached the highest value (30.80%) in Malkabi variety and the lowest one was 5.20% in Pertomoda after one month of storage. After three months of storage, Malkabi recorded the maximum value of the relative wet weight loss (28.84%), whereas the minimum value (6.55%) was recorded in Gondella. The results clear that all tested dry date varieties were infested with O. surinamensis and no immune variety was found free from the insect infestation with preference for tested varieties. The third part of the study screened the biological activity of some plant powders against the insect. The tested plant powders were Clove, Black pepper, Cinnamon, Thyme and Capsicum affected the biological characters of O. surinamensis with various degrees, it was found that both clove and cinnamon powders shortened the growth period, while thyme lasted the growth period compared to control. All tested powders reduced the progeny number compared to control but clove was the most promising which diet treatment with clove produced the least total progeny number (18.81) while those of capsicum achieved activity on progeny number (64.20) compared to control. Each of clove, black pepper, cinnamon and thyme reduced the adult emergence compared to control. In general, all tested powders reduced the percentage of weight loss compared with control, experiment. Powders of both clove and black pepper achieved good results compared to the other tested powders and could be applied with food grains to kill the adult stage and the immature stages and so reducing adult emergence.