Studies on effect of thirteen host plants on food consumption and some
biological aspects for larvae of the cotton leafworm, Spodoptera littoralis (Boisd.)
were carried out under laboratory conditions. The results revealed that, the highest
means of larval consumption were 0.355, 0.353 gm obtained from larva fed on tomato
leaves daily, followed by 0.34, 0.37 gm on lettuce daily, while the lowest means were
0.086, 0.089 gm of radish. The highest total consumption per larva of S. littoralis
were 6.13 and 6.20 gm, when larvae fed on tomato leaves, while the lowest total
consumption per larva were 1.43 and 1.15 gm, when larvae were fed on radish, in the
two generations, respectively. On the other hand, larvae that fed on turnip leaves had
the shortest larval duration 12.64 & 13.0 days, while those fed on zorbeyhh leaves
had the longest one 20.89 & 21.62 days, in the two generations, respectively. In the
case of pupae, the heaviest pupa (0.44& 0.44 gm) was obtained from larvae fed on
castor bean oil leaves. However, the lightest pupa (0.14 & 0.16g) was obtained from
larvae fed on Radish and zorbeyhh leaves, respectively in both generations. In the
case of the moth, longevity was also affected by larval food. Males and Females
emerging from larvae fed on tomato leaves had the longest life span 11.78 & 11.11
days, respectively; while males resulting from larvae fed on zorbeyhh leaves or
cabbage showed the shortest life span (5.89 & 5.95 days), but females produced from
larvae fed on purslane or pepper leaves had the shortest life span (5.17 & 5.56 days)
in the first generation. While males produced from larvae fed on pepper leaves or
cabbage showed the shortest life span (6.22 & 6.42 days); purslane or cabbage leaves
had the shortest life span (5.42 & 5.56 days) in the second generation. Female moths
produced from larvae fed on castor bean oil leaves laid the highest number of eggs
2171& 2139 eggs; but zorbeyhh produced the least number, 733.3 &766.9 eggs, in
the two generations, respectively.