Biocontrol potential of Chrysoperla zastrowi sillemi (Esben-Peterson) against greenhouse whitefly
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Date
2022-12-26
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CSK HPKV, Palampur
Abstract
The investigation entitled “Biocontrol potential of Chrysoperla zastrowi sillemi (Esben-Peterson)
against greenhouse whitefly” was carried out during the year 2021-22 in the Department of
Entomology, College of Agriculture, CSKHPKV, Palampur (HP), India to study important biological
parameters, morphometrics, feeding potential, prey preference and functional response of C. zastrowi
sillemi on two prey species viz. rice moth, Corcyra cephalonica and greenhouse whitefly (GHWF),
Trialeurodes vaporariorum under lab conditions (temperature 25±1oC, RH 65±5% and photoperiod
16L:8D). Biological parameters of the predator differed significantly on the two prey species. The third
instar had the longest duration on both the prey species (5.40 and 4.13 days, respectively). The total
larval duration was significantly higher on T. vaporariourum (10.20 days) than on C. cephalonica (9.13
days), however, the total developmental period was statistically at par, 20.53 days on rice moth eggs
and 20.83 days on GHWF. The overall survival rate of the larvae fed on C. cephalonica was
significantly higher (50%) than the larvae fed on T. vaporariourum (26.67%). The larval and total
growth indices were also observed to have significantly different values for male and females of the
predator on two different prey species. Oviposition period of the predator was higher (22.33 days) on
GHWF than on rice moth eggs (11.00 days), however, the number of fertile eggs/female was more on
former (52.60) than on the later prey (42.93). The total life span of male and female predator showed
variations on different prey species. Measurements of different life stages of the predator, reared on
different preys, did not show any significant difference except for the length and breadth of third larval
instar. During its whole larval period of 9 to 10days, a single larva of the predator consumed a total of
349.5, 351.3, 328.9 and 486.4 nymphs of first, second, third and fourth instar of GHWF, respectively.
The corresponding average consumption rates of the predator remained 33.52, 44.05, 33.66 and 38.46
nymphs per day. The predator exhibited preference for particular stage of the prey in no-choice
experiment, the younger instars of the predatory larva had more prey preference for younger nymphal
instars of GHWF and vice versa. All the predatory instars showed Type-II functional response. The
evaluated parameters indicated that the third instar had the maximum searching efficiency (0.125) and
lowest handling time (0.125h) than younger instars. Along with this the effectiveness of the third instar
of the predator was also estimated to be highest (1.003) and it also possessed maximum predation rate
(192.487). Study concluded that the chrysopid predator, C. zastrowi sillemi has very good biocontrol
potential against the strain of GHWF prevalent under agro-climatic conditions of Himachal Pradesh
and it can be effectively utilised for the management of the pest in an augmentative approach of
biological control and, therefore, further investigations are necessary to investigate its biocontrol
potential under field and greenhouse conditions.