BIOLOGICAL STUDIES ON THE MEALYBUG Icerya seychellarum (Westwood) (Homoptera, Margarodidae)

Document Type : Research articles.

Author

Department of Economic Entomology& pesticides Fac. Of Agric, Cairo University , Giza, Egypt

Abstract

The biology of the mealybug I. seychellarum was studied under
field and laboratory conditions. The insect passed through 4
generations/year. Males are not existed so parthenogensis is the only
way of reproduction. The average of eggs laid per female was 46.7+2.7.
Females fed on mango fruit laid more eggs than those fed on branches
or leaves. Eggs incubated at 35oC and 90% R.H. did not hatch. Eggs
incubated at 35oC with 70% R.H. hatched earlier than those at 15.0+1.0
oC with 90% R.H. with average duration 5.2+ 0.2 and 18.2+1.2 days,
respectively. The nymphal stage duration was 25.2+1.8 days during
summer and 42.8+1.8 days during winter at 33.0+1.0 with 50% R.H.
and 15.0+1.0oC with 60% R.H, respectively. In Spring and Autumn this
duration was 38.4+2.1and 33.4+2.4 days at 21.0+1.0oC with 55% R.H.
and 27.0+ 1.0oC with 70% R.H. respectively. Shortest preoviposition,
oviposition and postoviposition periods were 8.6+0.3, 7.6+1.2 and
9.6+0.2 days, respectively during Summer at 33.0+1.0oC with 50%
R.H., while these durations prolonged during Winter being 22.3+0.6,
13.3+1.7 and 16.5+1.7 days, respectively. In Spring averages of these
duration were 14.6+0.8, 10.8+0.5 and 14.1+1.4 days, respectively,
while averaged 10.5+0.5, 9.7+0.6 and 13.5+1.1 days during Autumn.
Female longevity averaged 25.8+1.7 and 52.1+3.2 days in Summer and
Winter, respectively. The life–cycle lasted for 55.2+3.7 and 107.4+5.4
days in Summer and Winter, respectively while averaged 87.7+5.0 and
74.8+4.5 days in Spring and Autumn.

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