STUDIES ON EGG PARASITOIDS Trichogramma species ON PINK BOLLWORM, Pectinophora gossypiella (Saunders) ON COTTON.
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Date
2019-07-22
Authors
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Dr. Punjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra.
Abstract
The present studies entitled “Studies on egg parasitoids Trichogramma species on pink bollworm, Pectinophora gossypiella (saunders) in cotton’’ was undertaken at laboratory conditions in the Insect Biocontrol Laboratory, ICAR-CICR, Nagpur during 2018-2019 covering the objectives, to identify the most effective species of Trichogramma from the available lab cultured species for parasitisation of pink bollworm eggs, to study the efficacy of parasitisation by Trichogramma species on pink bollworm reared from early and late season population in laboratory and to study the efficacy of parasitisation by
Trichogramma species at different temperatures.
Different species of Trichogramma used for the investigation are Trichogramma bactrae (Nagaraja), Trichogramma brasiliensis (Ashmead), Trichogramma japonicum (Ashmead) and Trichogramma chilonis (Ishii) @ four gravid females per a batch of hundred pink bollworm eggs. The fitness life parameters of all the four Trichogramma species such as per cent parasitisation, per cent adult emergence, developmental period, per cent unparasitised host eggs and per cent larval emergence from the host (pink bollworm) eggs were investigated under laboratory conditions. Among all the Trichogramma species the maximum per cent parasitisation and adult emergence was recorded by T. bactrae with 87.83 and 91.25 per cent, respectively when reared at room temperature conditions. However, the next best performance under the same laboratory conditions was recorded by T. chilonis with 83.83 per cent parasitisation and 88.66 per cent adult emergence.
On the early population of pink bollworm collected from the rosette flowers during the month of August from the control plots grown with non Bt cotton variety at ICAR- CICR, Nagpur the maximum per cent parasitisation (89.80%) and adult emergence (94.68%) was recorded under T. bactrae which was significantly superior over other Trichogramma species. Whereas, on the late population of pink bollworm collected from the infested cotton bolls during the month of Nov-Dec from the same plots, the performance of T. chilonis was significantly superior over
T. brasiliensis and T. japonicum and it was statistically at par with T. bactrae. However, there was no significant difference found in developmental period and per cent larval emergence from the pink bollworm eggs among all the treatments on both early and late population pink bollworm eggs.
Among different temperatures used to carry out the experiment T. bactrae was recorded with maximum per cent parasitisation and adult emergence at both 280C and 250C, where in per cent parasitisation recorded was 88.50 and
87.83 whereas 92.22 and 95.82 per cent adult emergence
was recorded at these two temperatures, respectively. Whereas, at 180C T. chilonis recorded highest per cent parasitisation i.e. 80.83 per cent and adult emergence recorded was 90.82 per cent. Non significant difference was found in developmental period and per cent host larval emergence from pink bollworm eggs among the treatments at different temperatures. However, the developmental period of all the Trichogramma species was recorded to decline with increase in temperature from 18, 25 and 280C. The development period ranged from 12.67 to 13.33 days at 180C and 9.50 to 10.50 days at 250C whereas only 6.00 to
7.00 days at 280C.
As per the study Trichogramma species i.e. T. brasiliensis (Ashmead) and T. japonicum (Ashmead) were recorded to be less effective in parasitising pink bollworm eggs. However one day old (24 hr) eggs of pink bollworm were the most preferred age group for parasitisation by all the Trichogramma species and their ability to parasitise
older eggs declined subsequently.
Description
It relates to quantify the parasitising ability of four different Trichogramma species against the eggs of pink bollworm, Pectinophora gossypiella (Saunders) along with their ability to emerge from the parasitised pink bollworm eggs at different laboratory conditions in order to identify the best performing species among all the others to be
recommended appropriately.
Keywords
Plant protection, control methods, biological control agents.
Citation
S, KU. ASHA. (2019). Studies on egg parasitoids Trichogramma species on pink bollworm, Pectinophora gossypiella (saunders) on cotton. Department of agricultural entomology,Nagpur. Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. M. Sc. 2019. Print. x, 87p. (unpublished).