الفهرس 
Introduction
Field studiesOnly 14 pages are availabe for public view
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Abstract
The potato tuber moth (PTM), Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae) occurs in many parts of the world. It is a serious pest of potato, tomato, eggplant, pepper and tobacco as well as a number of wild hosts. Therefore, the present investigation deals with some ecological and biological aspects of the potato tuber moth in the field and laboratory conditions which serve in achieving of some knowledge about the effective control of this pest. The obtained results could be summarized as follow : A Field studies : I Effect of some ecological factors on PTM population : 1 Host plant species : The highest population level occurred on potato followed by tomato and eggplant during both years of study. Pepper plants received the lowest population density throughout the whole period of investigation. Regarding host plants, the pest recorded three peaks of seasonal abundance on tomato, eggplant and pepper and the peak time was affected by host plant species. On potato plants, correlation analysis indicated that there was an insignificant negative (r = 0.256) and positive correlation (r = 0.319) between the plant age and PTM population during the first and second nili seasons. While, in summer plantation, there were highly significant positive correlations during the first and second season as ?r? values were 0.970** and 0.947**. So, it could be concluded that the relation between the plant age and PTM population depends on date of plantation. 2 Natural enemies : 21 Parasitoids : During the course of the present investigation, two hymenopterous parasitoids (namely Bracon instabilis Marshal and Apanteles litae Nixon) were recorded associated with PTM larvae. In potato nili plantation, both parasitoids were rarely observed on PTM larvae, especially the parasitoid A. litae. The average percentage of parasitism induced by two species together was 7.3(R+(B6.6 and 20.0(R+(B3.0% during the first and second season. Statistical analysis indicated that the correlation between PTM and B. instabilis populations was insignificant (r = 0.62 and 0.20) in the first and second season, also A. litae showed insignificantly positive correlation (r = 0.65) with PTM population in the first season, while the parasitoid not found in the second season. In potato summer plantation, B. instabilis was more abundant than A. litae in all sampling dates. The average percentage of parasitism was 14.76 and 9.21% during the first and second season. Statistical analysis indicated that the correlation between PTM and B. instabilis populations was highly significant positive (r = 0.67 and 0.71) in the first and second season. While, A. litae showed positively significant (r = 0.57) and highly significant (r = 0.67) correlation with PTM population in the first and second season. The results indicated that there was insignificant correlation between the parasitoid, B. instabilis population and both of mean temperature (r = 0.11 and 0.09) and relative humidity (r = 0.19 and 0.10) during the first and second nili seasons, respectively. Regression analysis of the effect of the weather factors (maximum, minimum and mean temperature in addition to the mean relative humidity) on the parasitoid population showed that the common effect of these factors represented by 7.8 and 38.5% on the parasitoid population changes in the first and second season.