BIOLOGICAL STUDIES ON THE CIGARETTE BEETLE, Lasioderma serricorne (F.) ON DIFFERENT BOTANICAL FOODS

The cigarette beetle, Lasioderma serricorne (F.) is a serious economic insect pest of many stored products, spices and dried fruits. This work was carried out in the Laboratory of Plant Protection Department, Faculty of Agriculture, Zagazig University, Egypt, to study the effect of eight different botanical foods as insect diets (standard insect rearing diet, wheat germ, oat grains, cumin seeds, corn flakes, chamomile flowers, roselle flowers and fenugreek seeds) on some biological aspects of this insect, population growth after one and three months as well as percentage of weight loss. Also, the effect of the heavy insect infestation on certain chemical constituents of the tested foods as food moisture content, total carbohydrates, total proteins, ash, total fats and total fibers was determined and compared to control after three months of storage. The standard insect rearing diet and wheat germ were the best foods since the insect larval period was very short (14.45 and 15.36 days, respectively), while fenugreek was less preferred food as larval diet (30.55 days). Pupal period ranged from 7.18 to 11.81 days on wheat germ and corn flakes, respectively. The shortest complete developmental period was 30.67 days on wheat germ and the longest one was 53.21 days on fenugreek seeds. Values of the susceptibility index ranged from 3.03 to 8.08% for fenugreek seeds and wheat germ, respectively. The standard insect rearing diet and wheat germ were the best food kinds since they produced the highest mean progeny number after one and three months of storage (204.33, 151.67 and 3151.30, 4313.30 adults, respectively). Mean weight loss percentage ranged from 0.52 to 5.20% on corn flakes and oat grains after one month from insect infestation, respectively. However, it reached its maximum value (31.13%) on the standard insect rearing diet and minimum value on cumin seeds (1.23%) after three months. The highest relative weight loss per each adult insect was 23.75% on chamomile flowers and the lowest one valued 2.66% on corn flakes after one month of storage. After three months the value increased on corn flakes, standard insect rearing diet, roselle flowers and cumin seeds, while decreased on the other tested food kinds. A positive correlation was found between the heavy insect infestation on some foods and the chemical constituents as moisture content, total carbohydrate, total proteins, total fats, ash and total fibers. In contrast a negative one was recorded on the other foods. Positive correlation coefficients with all tested chemical constituents on sound and infested foods were detected by highly significant for total carbohydrates and total proteins as well as significant for total fats. The heavy insect infestation increased both the progeny number and the incurred weight loss and affected the chemical constituents of the different tested food kinds compared to control. All tested food kinds were infested by the cigarette beetle L. serricorne and no immune food was found free from the insect infestation with preferable some tested food kinds to the insect. Moreover, the heavy insect infestation after three months affected the chemical constituents of the tested food kinds.