Abstract:
Two experiments were conducted to study the biology and damage assessment of papaya
mealybug. Biology of papaya mealybug studied in the laboratory of the department of
Entomology and damage assessment was conducted in the farm, Sher-e- Bangla Agricultural
University, Dhaka-1207 during June, 2017 to August, 2018. In damage assessment study, T
is covered with fine net and sprayed with imidacloprid, at 15 days interval to avoid mealybug
infestation and T
was infested by mealybug. The adult female laid 97-150 eggs with an
average 122.8. The ovipositional period and incubation period was 6.0 ± 1.22 days and 5.8
±1.09 days respectively. The female has three instars and male has four instars nymphs. At 1
2
instar male and female could not be distinguished. The average duration, length and breadth
of 1
st
instar nymph were 4.8± 0.83 days, 0.41± 0.08 mm, and 0.25 ± 0.03 mm. The average
duration of 2
nd
, 3
rd
instar female nymph and adult female was 4.2±0.83 mm, 3.4±0.54 mm
and 10± 2 days respectively. The average length of 2
nd
, 3
rd
female nymph and adult female
was 0.69± 0.03 mm, 1±0.14 mm and 1.94±0.27 mm respectively. The average breadth of 2
,
3
rd
female nymph and adult female was 0.44±0.02 mm, 0.72±0.05 mm and 1.38 ±0.05 mm
respectively. The average duration of 2
nd
, 3
rd
instar, pupa and adult male was 3.6± 0.54 days,
2.8 ± 0.83 days, 3.6 ±0.54 days and 2.4 ±.54 days respectively. The average length of 2
instar, pupa and adult male was 0.70±0.06 mm, 0.85±0.02 mm, 0.94±0.04 mm and 0.98
±0.03 mm respectively. The average breadth of 2
nd
, 3
rd
instar, 4
th
instar and adult male was
0.38 ±0.04 mm, 0.41 ±.02 mm, 0.26 ±0.03 mm, and 0.26±0.01 mm respectively. Mealybug
infestation reduced plant height (34.35%), number of leaves per plant (86.08%), petiole
length (53.31%), number of flowers per plant (86.23%), number of fruits per plant (89.43%),
individual fruit weight (88.01%) as well as total fruit yield per plant (98%).
nd
1
st
nd
, 3
rd
Description:
A Thesis
Submitted to the Department of Entomology,
Sher-e-Bangla Agricultural University, Dhaka
In partial fulfillment of the requirements
for the degree
of
MASTER OF SCIENCE (MS)
IN
ENTOMOLOY
SEMESTER: JANUARY - JUNE, 2018
