Bioecology and Management of Maladera insanabilis (Brenske) in Himachal Pradesh.
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Date
2019-09
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CSK HPKV, Palampur
Abstract
The beetles of Maladera species were collected from host trees and on UV and VL light traps at Kullu and Palampur during 2018-19. The Sericini beetles accounted for 22.45 and 33.40 per cent during March–September, and leading species were M. insanabilis, Maladera thomsoni, and Maladera sinaeivi. At Palampur, M. insanabilis, M. thomsoni and M. sinaeivi comprised 46.62-49.51, 38.57-41.02 and 7.52-11.7 per cent on light traps, whereas at Kullu, these species accounted for 29.75-34.63, 50.65-58.36 and 6.23-9.09 per cent of total Sericini beetle catch, respectively. The catches of M. insanabilis and M. thomsoni were 25-31.25 and 31.25-76.07 per cent higher on UV traps as compared to VL traps. On host trees, M. insanabilis and M. thomsoni were most predominant species at Palampur, and Kullu, respectively. To study food preference of beetles, toon and peach were found to be the most preferred host for M. insanabilis and M. thomsoni beetles in multi-choice tests. The biology of M. insanabilis and M. thomsoni was studied in laboratory at Palampur. The average length x width of newly laid eggs of M. insanabilis and M. thomsoni was recorded to be 1.16 ± 0.01 x 0.83 ± 0.03 mm and 1.14 ± 0.02 x 0.73 ± 0.04 mm. There are three larval instars, and the body lengths of the fully fed I-III instar grubs of M. insanabilis measured 3.08-4.43, 7.73-7.98 and 11.29-13.03 mm and the average width of head capsule was 0.91±0.01, 1.68±0.03 and 2.65±0.05 mm. The width of head capsule ranged from 0.85-0.99 mm. The fully fed I-III instar grubs of M. thomsoni measured 2.98-4.21, 7.15-7.45 and 8.53-
9.15 mm, and width of head capsule averaged 0.89±0.01, 1.23±0.01 and 1.91±0.04 mm, respectively. Duration of the first, second and third instar grubs was 20-25, 23-28 and 180-190 days in M. insanabilis. In M. thomsoni, the first, second and third instar grubs occupied 18-20, 20-24 and 174-189 days, respectively. Total larval period was recorded to be of 225-243 and 212-233 days for M. insanabilis and M. thomsoni, respectively. The detailed description of the labrum, clypeus, mandibles, epipharynx, maxillae, legs, spiracles and rasters of the third instar grubs is given with the help of suitable diagrams. The rasters of M. insanabilis and M. thomsoni have a single, transverse row of spines arranged in a crescent shape. In M. insanabilis, the length x width of pupae was recorded to be 12.04 ± 0.39 x 6.81 ±
mm, whereas in M. thomsoni, the length x width of pupa ranged from 10.81 ± 0.18 x 6.49 ± 0.07 mm. The pupal period was 13.20 ± 1.61 days and 11.60 ± 1.48 days. The adult formation occurred during May in M. insanabilis, and in April for M. thomsoni. The beetles of M. insanabilis are reddish-brown and in case of M. thomsoni, yellowish brown to light brown in colour. The females (8.32 x 5.38mm - 4.47 x 3.183 mm) were slightly larger than the males (7.32 x 4.47mm - 4.48 x 2.43 mm). The antennal clubs revealed significant differences in size among species and sexes. In males of M. insanabilis and M. thomsoni the length of lamellae was 0.456 and 0.294 mm, and the corresponding value was 0.398 and 0.269 mm in female beetles. In forelegs, the claws are clefted and bifid in females, and trifid in males. Male genitalia are trumpet shaped in M. thomsoni and more or less flask shaped in M. insanabilis. Female beetle survived for 30.20±2.65 days in M. insanabilis and 35.50±2.57 days in M. thomsoni. The mean longevity of male beetles was recorded to be 26.20±2.15 days and 26.30±3.11 days, respectively. Against M. insanabilis, four insecticides and three natural products were tested. The LC50 values of dimethoate, flubendiamide, chlorpyriphos and spinosad were calculated to be 7.08, 109.16, 128.62 and 153.62 ppm. In case of natural products, Agniastra, Brahmastra and Neemastra were evaluated, and FD50 values were calculated to be 5.62, 7.71 and 11.01 per cent, respectively.
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