MONITORING AND MANAGEMENT OF COTTON PINK BOLLWORM, Pectinophora gossypiella Saunders (GELECHIIDAE: LEPIDOPTERA)
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Date
2022-08-10
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guntur
Abstract
The present study entitled “Monitoring and Management of Cotton Pink Bollworm, Pectinophora gossypiella Saunders (Gelechiidae: Lepidoptera)” was carried out during 2018-19 and 2019- 20. The objectives are; to assess the incidence of pink bollworm in different cotton-growing regions of Andhra Pradesh, management of pink bollworm by mating disruption technique, assessment of the sources and carryover of PBW incidence during the offseason, studies on the screening F2 population of PBW for resistance alleles to Cry toxins, and molecular characterization of Andhra Pradesh Pink bollworm populations. The last two studies were done at Central Institute for Cotton Research (ICAR-CICR) Nagpur, Maharashtra.
The insect was recovered from all the 12 sampled locations. Significant differences were observed across the mandals and among different survey dates. In 2018-19 the average damage to flowers was 14.64% for all the 12 mandals of three districts. However, the boll damage recorded was 52.27%, with an average of 0.84 larvae/boll. The per cent locule damage recorded was 31.50%. Likewise, in 2019-20, the average flower damage recorded was 16.38% and boll damage was 53.62% with 0.86 larvae/boll. The per cent locule damage recorded was 34.19%.
Results obtained from the study of carryover mechanisms of pink bollworm in Andhra Pradesh revealed that in 2018-19, an average of 371.47 moths/trap/fortnight were trapped at ginning mills in the Guntur district. The fortnight interval catches ranged from 21.80 on 30th July to the maximum of 1237.80 on 30th March 2019. In 2019-20, an average of 466.0 moths/trap/fortnight were recovered. The fortnight interval catches ranged from 30 on 30th July to 1376 on 30th March 2020.
The studies on the role of ginning waste in the carryover of the pest were conducted during the offseason. From the collected sample of 10 kg of ginning waste, the average number of live larvae, pupae, and double seeds were 63.57, 21.35, and 18.64 in 2019 and 70.35, 24.42, 20.78 in 2020. The average male and female moths
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were 57.71 and 85.71 in 2019 and 60.71 and 95 in 2020. The damage was 1.5 and 1.8 per cent on mesta, whereas on bhendi it was 2.7 and 3.5 per cent. It is indicated that the alternate host plants of the Malvaceae family are supporting this pest only to a limited extent, and most of the pest population is carried through seed cotton in ginning mills.
The frequency of Cry1Ac resistance alleles in PBW collected from Andhra Pradesh was estimated to be 0.082 with a 95% CI of 0.051 – 0.105, and the frequency of Cry2Ab resistance alleles was estimated to be 0.054 with a 95% CI of 0.029 – 0.077. We report a high frequency of Cry1Ac and Cry2Ab resistance alleles in the field population collected from Andhra Pradesh. A < 3% probability of missing a resistance allele in 66 lines screened for Cry1Ac and Cry2Ab resistance.
The descriptive statistics Haplotype (gene) diversity (Hd), Variance of Haplotype diversity, and Standard Deviation of Haplotype diversity were measured with DnaSP ver. 5.10.01 software in a phylogenetic study of P. gossypiella and found to be 0.853, 0.00283, and 0.053 respectively, suggesting that the entire population had a low degree of genetic diversity.
The per cent mating disruption results revealed that the treated plot moth catches ranged from 0.2 to 10.2 per trap per week, and the average moth catch was 3.55 moths/trap/week. In the control plot, moth catches ranged from 2.2 to 89.6 per trap per week, and the average was 40.82 moths per trap per week. Per cent disruption ranged from 81.8 to 99.0, and mean disruption was 91.3% in 2018-19. Similarly, in 2019-20 the treated plot moth catches ranged from 0.6 to 26.8 per trap per week, and the average moth catch was 8.3 moths /trap/week. In control, plot moth catches ranged from 3.6 to 90.1 per trap per week, and the average was 51.9 moths per trap per week. Per cent disruption ranged from 70.3 to 96.8, and mean disruption was 84.1%.
Description
MONITORING AND MANAGEMENT OF COTTON PINK BOLLWORM, Pectinophora gossypiella Saunders (GELECHIIDAE: LEPIDOPTERA)