Pink bollworm, Pectinophora gossypiella (Saunders) infestation on Bt cotton is a major concern to cotton production in India. The genetic diversity and phylogeographic structure of the insect in ...light of PBW resistance needs to be revisited. The objective of this study was to identify different haplotypes of pink bollworm and their distribution in India. To achieve this we studied the population structure in 44 cotton growing districts of India. The partial mitochondrial COI sequence analyses of 214 pink bollworm populations collected from 44 geographical locations representing 9 cotton growing states of India were analysed. Genetic diversity analysis exhibited presence of 27 haplotypes, among them Pg_H1 and Pg_H2 were the most common and were present in 143 and 32 populations, respectively. Distributions of pairwise differences obtained with partial COI gene data from the overall Indian populations are unimodal, suggesting population expansion in India. Significant neutrality test on the basis of Tajima' D and Fu's Fs presented a star-shaped haplotype network together with multiple haplotypes. The unimodal mismatch distribution, rejection of neutrality test with significant negative values supported the theory of demographic expansion in cotton pink bollworm populations in India. Genetic data not only provides us with a perspective of population genetics, but also that the two populations of pink bollworm, those occurring early in the season are genetically close to the late season populations with respect to their partial CO1 region. Resistance to Cry toxins does not seem to have had an impact on this region of the mt DNA in populations of pink bollworm.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
There is a global concern about the effects of climate change driven shifts in species phenology on crop pests. Using geographically and temporally extensive data set of moth trap catches and ...temperatures across the cotton growing states of India, we predicted the phenology of cotton pink bollworm Pectinophora gossypiella (Saunders). Our approach was centered on growing degree days (GDD), a measure of thermal accumulation that provides a mechanistic link between climate change and species' phenology. The phenology change was predicted by calculating absolute error associated with DD and ordinal date, an alternative predictor of phenology, for peak moth abundance. Our results show that GDD outperformed the ordinal dates in predicting peak moth abundance in 6 out of 10 selected locations. Using established thresholds of 13.0/34.0 °C, mean DD accumulated between the consecutive moth peaks across different years were estimated at 504.05 ± 4.84. Seven generations were determined for pink bollworm in a cropping season, the length of which varied between 35 and 73 days in response to temperature. Pink bollworm population reached its peak during third generation which can be the target for management actions. The study provides essential information for developing pink bollworm management strategies under climate change.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pink Bollworm (PBW) incidence on Bollgard-II (BG II) cotton was not observed so far in North Zone of India. During 2018–19 cotton season, BG II cotton was found infested with Pink Bollworm at one ...location in Haryana and two locations in Punjab near cotton ginning and oil extraction units. Cotton seeds are being procured from the central and south India by many units where PBW has already acquired resistance against BG II hybrids. Bio-ecological and resistance monitoring studies of larvae collected from the infested location revealed absence of larval diapauses in surviving population and resistance levels equivalent to central/south zone populations. The threat perception of pink bollworm in north zone on BG II cotton due to transport of resistant larvae along with cotton seed is discussed.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background
Insecticidal proteins from the
Bacillus thuringiensis
(
Bt
) marks the genetically modified cotton crop that was commercialized in India in March 2002 for the control of lepidopteron ...bollworms. Despite organized initial control, the pink bollworm (PBW),
Pectinophora gossypiella
(Saunders), adapted itself to cry toxins resulted in field control failures in 2016 and 2017. The present study was designed to understand the survival and development of PBW populations differing in susceptibility to Cry toxins on Bt and non-Bt plants.
Results
For assessment of infestation, populations were collected from different cotton growing states. Per cent infestation of flowers and green bolls in the study areas were in the range of 3.09–29.26 and 36–91.20% for flowers and green bolls, respectively. Among different locations highest magnitude of resistance to Cry1Ac (371.8-fold) and Cry2Ab (4214.3-fold) was spotted in late season populations of Rajkot collected from bolls. Further, in order to confirm field level resistance of surviving larvae on high and low concentrations of Cry toxins, larvae were pooled and subjected to boll bioassays. Results revealed that, none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non-
Bt
cotton. Maximum survival (32%) and locule damage (70%) was observed for Maharashtra (F-H) Cry2Ab and Gujarat (B-H) Cry2Ab populations recorded 36% survival and 70% mortality, respectively, on BGII cotton and 58.33% survival and 60% locule damage on non-
Bt
cotton, respectively. Populations derived from survivals on low concentrations produced the lowest survival and locule damage on
Bt
cotton. Maximum number of mines on epicarp (2.4 mines/boll) was recorded by susceptible population on NBt cotton. Green bolls of
Bt
and NBt cotton did not differ in the number of mines.
Conclusion
It was concluded that none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non-
Bt
cotton
Oxycetonia versicolor
Fabricius (flower chafer beetle) was documented as a pest on cotton from central India for the first time. The survey was undertaken to understand the infestation levels on ...cotton. Results revealed that low-to-moderate level infestation was observed in the surveyed districts. Damage of 12.92% was noticed in Rajkot, Gujarat, while negligible damage recorded in Wardha, Maharashtra (0.40%), India.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Aim: The holistic management of pink bollworm is possible only after uncovering the underlying mechanism/s of pink bollworm resistance. The present study was carried out for investigating the effect ...of Cry2Ab toxin on alkaline phosphatase activity and expression of its isoforms in midgut of Pectinophora gossypiella. Methodology: Resistant and susceptible pink bollworm larval populations were subjected to Cry2Ab bioassays using F1 larvae in a 21 days diet-incorporation method. The total midgut protein was estimated by Bradford method. Alkaline phosphatase activity was estimated in midgut homogenates, Non-denaturing SDS-PAGE and Native polyacrylamide gel electrophoresis was performed by the following standard procedures. Results: The study showed increased alkaline phosphatase activity in pink bollworm midgut is correlated with insect resistance in response to Cry2Ab. The non-denaturing SDS-PAGE analysis of pink bollworm midgut alkaline phosphatase isozymes had differential banding patterns in resistant and susceptible populations. Yavatmal (R1), Hingoli (R4) and Parbhani (R5) showed similar banding patterns ranging from 65-95 kDa; Guntur (R2) and Hingoli (R3) showed near similar banding patterns ranging from 70-95 kDa; whereas susceptible population showed banding pattern in the range of 50-70 kDa. Interpretation: The expression profiles of alkaline phosphatase isomers in resistant and susceptible populations can be utilized as a biomarker to aid for the screening of PBW infected Bt -cotton fields and development of pink bollworm management strategies. Key words: Alkaline Phosphatase, Cry2Ab, Insect resistance, Pectinophora gossypiella, SDS-PAGE
Background
After the commercialization of insect-resistant transgenic
Bt
cotton Bollgard I & II, India ranks first in the world in cotton production. Cotton insecticide consumption was drastically ...reduced as nearly 95% of the cotton area was replaced with Bollgard II. However, the benefits of transgenic cotton appear to have been diminished as the pink bollworm,
Pectinophora gossypiella
(Saunders) (Lepidoptera: Gelechiidae) developed field resistance to Cry1Ac expressing
Bt
cotton in India in 2008. In 2015, there was an unusual survival of
P. gossypiella
on Bollgard II cotton in some parts of Gujarat and Maharashtra, which is a cause for concern.
Results
In the present study, PCR analysis and gel visualization of BGII resistant field population of
P. gossypiella
showed that the presence of r1, r2, r3, r1s, r2s, r3s, and ss mutated cadherin alleles, which produced amplicon sizes of 750 bp, 700 bp, 730 bp, 12,700 bp, 750 bp, 980 bp, 600 bp and 1600 bp, respectively, when seven different types of cadherin allele(s) specific primers were used. The r1 mutant allele was detected in Amaravati, Wardha, Yavatmal, and Nagpur, but not in Akola and Buldhana, using primers r1disfor and Int-540. The r2 mutant allele was detected in Akola, Wardha, and Nagpur, but not in Buldhana, Amaravati, and Yavatmal, using primers r2disback and Cad2366. The r3 mutant allele was detected in all locations using primers r3disback and Cad3221. Amplicons of sizes 750 bp, 700 bp and 730 bp were obtained for r1, r2, and r3 mutant alleles, respectively. The sizes of the amplicons were 1270 bp for r1s, 750 bp for r2s, and 980 bp for r3s.The absence of bands for r1, r2, and r3 cadherin alleles in individuals indicated the possibility of having the ss allele, which was confirmed using primers Cad3324 and Int-651. The presence of ss mutant allele was observed in field-collected
P. gossypiella
populations from BG II cotton in various locations, with a 600 bp and 1600 bp size amplicons produced using the same primers.
Conclusions
PCR analysis revealed the presence of r1, r2, r3, r1s, r2s, r3s, and ss mutated cadherin alleles in field-collected populations of Vidarbha which provide evidence to field-evolved resistance of
P. gossypiella
to BGII cotton.
Pink bollworm (PBW), Pectinophora gossypiella is one of the most destructive pest's globally inflicting huge economic losses in cotton even during later stages of crop growth. In the present ...investigation, the population genetic structure, distribution, and genetic diversity of P. gossypiella in cotton growing zones of India using partial mitochondrial DNA cytochrome oxidase-I (COI) gene was addressed. The overall haplotype (Hd), number of nucleotide differences (K), and nucleotide diversity (π) were 0.3028, 0.327, and 0.00047, respectively which suggest that entire population exhibited low level of genetic diversity. Zone-wise clustering of population revealed that central zone recorded low level of Hd (0.2730) as compared to north (0.3619) and south (0.3028) zones. The most common haplotype (H1) reported in all 19 locations could be proposed as ancestral/original haplotype. This haplotype with one mutational step formed star-like phylogeny connected with 11 other haplotypes. The phylogenetic relationship studies revealed that most haplotypes of populations are closely related to each other. Haplotype 5 was exclusively present in Dharwad (South zone) shared with populations of Hanumangarh and Bathinda (North zone). The result indicated that there is no isolation by distance effect among the Indian populations of PBW. The present study reports a low genetic diversity among PBW populations of India and H1, as ancestral haplotype from which other haplotypes have evolved suggests that the migration and dispersal over long distance and invasiveness are major factors.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Cotton seed based artificial diet has been standardized for continuous rearing of pink bollworm Pectinophora gossypiella (Saunders) at the Central Institute for Cotton Research, Regional Station, ...Coimbatore. The ingredients of the diet are easily available and are cost effective. Basic ingredients of the diet are cotton seed flour (processed) and chick pea flour, Carbohydrate, Protein, Fat sources, multi vitamin, antimicrobial agents and agar as thickening agent are used as other ingredients. Micro centrifuge tubes with lid were used as rearing containers. Individual neonate larvae were released on each piece of the diet inside the micro centrifuge tube and the lids were closed. This prevented larval escape, retaining them inside the tubes and also prevented diet dehydration. The recovery of insect reared on diet was recorded as 95.56%. Egg hatchability and adult emergence were 100% while pupal malformation was nil. Eggs, larval and pupal periods were recorded as 4.8±0.632, 25.10±0.994 and 7.9±0.88days, respectively. Larval and pupal weights were recorded as 21.40mg±3.63, 18.00mg±2.73, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
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