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BIOLOGY, FEEDING POTENTIAL AND TO ASCERTAIN SAFER INSECTICIDES FOR PREDATOR, Cryptolaemus montrouzieri MULSANT ON THE COTTON MEALY BUG
| Content Provider | KrishiKosh-Indian National Agricultural Research System |
|---|---|
| Advisor | Patel, V. N. |
| Researcher | Kakde, A. M. |
| Abstract | Investigations on biology, feeding potential and ascertain of safer insecticides for predator, Cryptolaemus montrouzieri Mulsant on the cotton mealy bug were carried out in department of entomology, College of Agriculture, Junagadh Agricultural University, Junagadh during Kharif 2010. Studies on biology of the mealy bug predator, C. montrouzieri were carried out at an average temperature of 19.76 to 29.20¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬0C with the relative humidity of 72 to 80 per cent under laboratory condition. Female of C. montrouzieri laid eggs mostly in the ovisacs or in the mealy bugs colony, either singly or in group of 4 to 8. The newly laid eggs were pale yellowish white, smooth and cylindrical. The average incubation period was 3 to 6 days with an average of 4.40  0.88 days. At the time of hatching, shining of eggs disappeared and longitudinal depressions were seen. Hatching of 80 per cent of the eggs was recorded. The grubs of C. montrouzieri passed through different four instars. Soon after emergence 1st instar grub was light yellow in colour. Within few hours, body was covered with a white bloom. Duration of the first instar grub was varied from 2 to 4 days with an average of 2.90 ± 0.79 days. The freshly moulted second instar grub was covered with waxy coating. After that, the body was gradually covered with waxy filaments on dorsum of thorax and abdomen. Duration of the second instar grub was varied from 3 to 6 days with an average of 4.85 ± 0.88 days. Immediately after moulting, the body of the third instar grub was found to be smooth and lemon yellow in colour. Within few hours, a whitish bloom appeared on body and subsequently white waxy filaments developed on the dorsum of thorax and abdomen. Duration of the third instar grub was varied from 5 to 7 days with an average of 6.45 ± 0.83 days. The fourth instar grub was fully covered with waxy coating within few hours after moulting and subsequently white waxy filaments developed on the dorsum of thorax and abdomen. Duration of the fourth instar grub was varied from 3 to 5 days with an average of 3.85 ± 0.75 days. Total grub period was 13 to 21 days with an average of 18.05 ± 2.04 days. It was observed that the grub underwent a pre-pupal stage which lasted for 1 to 3 days with an average of 2.30 ± 0.73 days. During this period, the grub become inactive, remained isolated, stopped feeding and some body fluid was oozed out. The pupae resembled a typical coccinellid pupae in all aspects. It was observed that most of the full grown grubs climbed down and reached at dark shady places in the cage for pupation. However, a few of them were pupated on bottom side. Pupa was reddish brown in colour. The pupal period was varied from 7 to 10 days with an average of 8.95 ± 1.05 days. The pupa was fully covered dorsally with the white waxy filaments and the larval exuvium. The total development period of C. montrouzieri (from egg to adult formation) was 23 to 37 days with an average of 32.75 ± 3.58 days. The adults of C. montrouzieri were ellipsoid and have typical form of lady bird beetles. The phenomenon of sexual dimorphism was observed in adults of C. montrouzieri. The male and female could be distinguished by colour difference in the first pair of legs. The adult emergence and sex ratio (male: female) were recorded as 90 per cent and 1: 1.25, respectively. The pre-mating and mating periods of the predator was varied from 4 to 8 days with an average of 5.10 ± 1.29 days and 12 to 20 minutes with an average of 15.90 ± 3.03 minutes, respectively. The pre-oviposition, oviposition and post-oviposition periods were recorded as 6 to 8 days with an average of 7.40 ± 0.70 days, 42 to 47 days with an average of 45.70 ± 1.49 days and 6 to 8 days with an average of 7.60 ± 0.70 days, respectively. The average egg laying capacity of a single female was 98 to 102 with an average of 99.70 ± 1.70 eggs. The longevity of male was 64 to 68 days with an average of 66.60  1.35 days. While, the female lived for 58 to 62 days with an average of 60.50  1.58 days. The entire life span for the male was varied from 98 to 103 days with an average of 99.20  1.55 days. While, that of the female was 90 to 95 days with an average of 93.10  1.85 days. The study on predatory potential of the predator, C. montrouzieri revealed that both the stages (adults and grubs), feed extensively on egg, nymph (2nd instar) and adult stages of the mealy bug, P. solenopsis. But the grubs (larvae) were more voracious feeder. A single grub of the predator consumed minimum of 727 eggs and maximum 764 eggs with an average of 746 eggs of the cotton mealy bug. A pair of adult (female and male) of the predatory beetle consumed 7761 to 7923 eggs with an average of 7847 eggs. A female consumed more eggs (4326) than a male (3520 eggs). Further, it was found that the grubs of the predator fed on the nymphal instar (2nd) of the cotton mealy bug, a single grub consumed 218 nymphs and a adult consumed 189 nymphs for its development. About 17 adult female mealy bugs required to complete the development of adult stage of the predator. Residual toxicity of ten insecticides were evaluated against grub and adult stages of the mealy bug predator C. montrouzieri. The results revealed that none of the insecticide was safe for the predator. However, the endosulfan 0.07 per cent was relatively safer as it caused initial mortality of 51 per cent and the mortality was decreased on increased hours after application (44, 36, 24 and 17 per cent mortality on 24, 48, 72 and 96 hours old residues). Thiamethoxam 0.01 per cent was next safer insecticides which caused mortality of 63 per cent initially and thereafter the mortality was decreased to 31 per cent on 96 hours old residues. Monocrotophos 0.036 per cent, quinalphos 0.05 per cent, malathion 0.1 per cent, imidacloprid 0.005 per cent, prophenophos 0.05 per cent and acetamiprid 0.004 per cent were found highly toxic to the predator, as they caused more than 80 per cent mortality. Methyl-parathion 0.1 per cent was comparatively less toxic to the predator which caused 77 to 45 per cent mortality of the predator. |
| Page Count | 119 |
| File Size | 133884824 |
| File Format | |
| Language | English |
| Publisher | JAU |
| Publisher Place | Junagadh |
| Access Restriction | Open |
| Subject Keyword | Entomology Biology Feeding Potential and To Ascertain Safer Insecticides For Predator Cryptolaemus Montrouzieri Mulsant On The Cotton Mealy Bug |
| Content Type | Text |
| Educational Degree | Master of Science (M.Sc.) |
| Resource Type | Thesis |
