BIOLOGY, PREDATORY POTENTIAL OF Cryptolaemus montrouzieri Mulsant ON PAPAYA MEALYBUG AND SAFETY EVALUATION OF CERTAIN INSECTICIDES ON PREDATOR
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Date
2017
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Acharya N.G. Ranga Agricultural University
Abstract
The present studies on “Biology, Predatory potential of Cryptolaemus
montrouzieri Mulsant on papaya mealybug and Safety evaluation of certain
insecticides on predator’’ were carried out at Insectary, Department of
Entomology, S.V. Agricultural College, Tirupati during 2016-17. Biology
including morphometrics, predatory potential of C. montrouzieri on papaya
mealybug, biology on different life stages of papaya mealybug and evaluation
of toxicity of different insecticides on predator were studied.
Studies on the biology of C. montrouzieri on Paracoccus marginatus
revealed that the oviposition period, male longevity and female longevity was
43.60 ± 2.95, 70.70 ± 2.75 and 77.30 ± 5.03 days, respectively. The mean egg
period, duration of I, II, III and IV instars, pre- pupa and pupa was 3.13 ± 1.12,
2.96 ± 0.65, 4.30 ± 0.57, 5.73 ± 0.75 and 6.40 ± 0.78, 2.30 ± 0.49 and 7.50 ± 0.96
days, respectively. The total grub period and developmental period i.e. from
egg to adult was found to be 22.50 ± 1.33 and 32.30 ± 1.55 days, respectively.
The mean fecundity of female was 272.60 and sex ratio was 1: 1.
The morphometrics of the C. montrouzieri revealed that the average
length and breadth of egg was 0.81 ± 0.05 mm and 0.41 ± 0.04 mm. Similarly,
the average length and breadth of I, II, III and IV instar grubs was 1.26 ± 0.26 mm
and 0.49 ± 0.05 mm; 4.60 ± 0.47 mm and 1.17 ± 0.08 mm; 6.06 ± 0.53 mm
and 2.00 ± 0.30 mm; 8.44 ± 0.64 mm and 4.12 ± 0.15 mm, respectively. The
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average length and breadth of pre- pupa and pupa was found to be 8.96 ± 0.36 mm
and 4.30 ± 0.35 mm; 9.08 ± 0.46 and 4.32 ± 0.58 mm, respectively. The
average length and breadth of adult male and adult female was 3.85 ± 0.24 mm
and 2.89 ± 0.12 mm; 4.25 ± 0.28 mm and 3.20 ± 0.20 mm.
The total developmental period of C. montrouzieri was significantly
highest when reared on ovisacs of papaya mealybug, when compared to that
of I, II and III instar nymphs of P. marginatus.
Feeding potential of C. montrouzieri on different stages of papaya
mealybug was studied. The mean predatory potential of I, II, III and IV instar
grub on Ovisac, I, II and III instar nymphs of mealybug was 1.40 ± 0.12,
30.60 ± 0.51, 20.53 ± 0.98 and 13.46 ± 1.15; 1.68 ± 0.13, 43.52 ± 0.41, 30.40
± 0.68 and 17.33 ± 0.88; 1.90 ± 0.14, 47.04 ± 0.84, 31.56 ± 0.51 and 20.45 ±
0.84 and 1.91 ± 0.15, 54.10 ± 0.45, 38.20 ± 0.58 and 26.32 ± 1.13. Average
consumption capacity of male and female on ovisac, I, II and III instar
nymphs was 2.98 ± 0.09, 57.81 ± 0.24, 41.39 ± 0.12 and 28.51 ± 0.02 and
3.05 ± 0.10, 58.19 ± 0.26, 43.00 ± 0.19 and 29.28 ± 0.08, respectively.
Among safety evaluation of different insecticides on life stages of
C. montrouzieri, dimethoate was found to be highly toxic whereas, flonicamid,
buprofezin and neem oil were found to be non-toxic through food contamination
method. In dry film method, acephate was highly toxic while, buprofezin and
neem oil were least toxic to all the stages of the predator
Description
D5510
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