تأثير المستخلصات النباتية لنبات سم الفراخ (Withania somnifera (L.)‎ Dunal.)‎ في الأداء الحياتي لدودة ورق القطن (Spodoptera littoralis Boisd.)‎

الملخص EN

This study was conducted to determine the effect of ethanol and hexane extracts of withania somnifera on the larvae of the cotton leaf worm Spodoptera littoralis when the 2nd and 4th larvae instars were fed on food treated with plant extract concentrations of 1.25, 2.5 and 5%.

The results showed that the 2nd instar larvae were the most susceptible than the late ones.

The highest mortality rate reached 58.52% for the 2nd instar larvae and 20.74% for the 4th ones when 5% ethanol extract concentration was used.

The results pointed to prolonged durations of the larval and pupal stages depending on the extract concentration used.

The longest period of growth stage was found for the treatment with 5% hexane extract concentration.

The fertility rate of adults emerged from treated larvae was decreased.

The numbers of eggs laid was 670 eggs/female and the egg hatching rate reached 71% when 5% extract concentration was used to treat 2nd larvae instars.