International Journal of Horticulture, 2016, Vol.6, No.4, 1-6
2
considered to be of great economic importance in agro-ecosystem as they can be successfully employed in the
biological control of many injurious insects (Agarwal et al
.,
1988).
In India the coccinellid beetle,
Cryptolaemus montrouzieri
Mulsant (Coleoptera: Coccinellidae) has provided
spectacular control of heavy infestations of sucking pests, especially mealy bugs (Mani, 1990; Mani and
Krishnamoorthy, 2008) and some soft scales (Kumar and Prakasam, 1984; Mani and Krishnamoorthy, 1990). The
predator was also reported to feed on citrus mealy bug,
Planococcus citri
(Risso) (Singh, 1978) and pink mealy
bug,
M. hirsutus
(Mani and Thontadarya, 1987; Reddy and Narayan, 1986).
Cryptolaemus montrouzieri
was
found to be almost efficient predator among coccinellids in India (Fandi et al
.,
2010). Despite the frequent use of
different predators, only the coccinellid,
C. montrouzieri
can be considered successful (Moore, 1988). The
coccinellid beetle,
C. montrouzieri
can be effectively utilized in the management of pink hibiscus mealy bug
M.
hirsutus
and papaya mealy bug (Mishra et al., 2012). Keeping in mind the efficacy of
C. montrouzieri
on mealy
bug species, the present study was conducted to estimate the biology of
C. montrouzieri
on different stages of
M.
hirsutus
a pest of grape vine in India.
Results
Bio-ecology of
Cryptolaemus montrouzieri
The studies on bio-ecology of
C. montrouzieri
revealed that, the pre-mating and pre-oviposition period was found
with an average of 6.00 ±2.06 and 8.70 ±1.64 days, respectively. Whereas, oviposition period lasted for 73.80 ±
13.02 days. The male and female adult lived with an average of 78.00±10.83 and 88.50±14.86 days, respectively
(Table 1). The freshly laid eggs were pale yellowish white, smooth and cylindrical in shape. At the time of
hatching the shining of egg disappeared and a longitudinal depression was seen on the eggs. The egg laying
capacity of female beetle was recorded with a mean of 550.30 ±62.68 eggs when fed with all the stages of mealy
bugs. The grubs emerged out through eggs by breaking at the weak point of this longitudinal depression. The
incubation period lasted for 5.75 ±0.72 days with egg hatching percentage of 95.
Table 1 Mating period, oviposition period, adult longevity, fecundity, incubation period and hatching percentage of
Cryptolaemus montrouzieri
Particulars
Pre-mating
period
(Days)
Pre-oviposition
period (Days)
Oviposition
period
(Days)
Adult longevity (Days)
Total
number of
eggs laid
Incubation
period
(Days)
Hatching
(%)
Male
Female
Range
4-9
6-11
58-89
61-91
72-109
472-652
3.6-7.9
80-100
Average
6.00 ±2.06 8.70 ±1.64
73.80
±
13.02
78.00
±
10.83
88.50
±
14.86
550.30
±
62.68
5.75
±
0.72
95
Note: Observations on 10 adults per replication
Developmental period of
Cryptolaemus montrouzieri
Results on the developmental period of grubs and adults on different stages of
M. hirsutus
indicated that the grub
period was extended when reared on second instar mealy bugs compared to rearing on third instar mealy bugs.
The newly hatched grubs were smooth and pale greyish in colour. They were devoid of wax strands at the time of
hatching but developed within 2 to 3 hours of hatching. The length of these wax strands were found increasing
with each instars. The grubs moulted three times during their post embryonic development before undergoing
pupation, exhibiting four instars. This difference in the developmental period of grubs and adults reared on
different stages of the mealy bugs may be due to the quality and quantity of the prey offered to the predator. The
predatory grub took 3.83 ±0.53, 4.83 ±0.65, 6.03 ±0.85 and 5.67 ±0.66 days to complete its first, second, third
and fourth instar, respectively (Table 2) when supplemented with second instar mealy bugs while, 3.53 ±0.51,
4.53 ±0.51, 5.57 ±0.50 and 5.50 ±0.51 days when fed on third instar mealy bugs with an average of 3.68 ±0.36,
4.68 ±0.33, 5.80 ±0.57 and 5.58 ±0.46 days, respectively (Figure 1).
The total developmental period of grubs was 20.37 ±1.29 and 19.13 ±0.86 with an average of 19.75 ±0.77 when
supplemented with second and third instar mealy bug preys, respectively. The predator grubs recorded pre pupal
