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Background: The pink bollworm, Pectinophora gossypiella (Saunders), is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-II® cotton plants in recent years due to the evolution of Bt resistance. The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops. Hence, the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant (Field-R) and susceptible (Lab-S) population. Results: Prolonged larval duration (23.40 days in Field-R vs 18.80 days in Lab-S population), total life cycle (male = 50.00 vs 42.80 days; female = 53.60 vs 46.20 days), reduced fecundity (100.60 vs 154.20 eggs/female) and fertility (88.00 vs 138.00 fertile eggs/female) was observed. The demographic parameters indicated a significant reduction in the net reproductive rate (184.27 vs 276.72), innate capacity for increase in number (0.11 vs 0.15), finite rate of increase in number (1.12 vs 1.16 female progenies produced/female/day), weekly multiplication rate (2.16 vs 2.86), potential fecundity (545.06 vs 634.11 eggs), number of hypothetical F2 females (33 955.65 vs 76 572.41), but longer mean length of generation (47.54 vs 37.74 days) and population doubling time (6.30 vs 4.62 days) in Field-R compared with Lab-S population. A stage-specific life table demonstrated the differences in survival rates between susceptible and resistant populations at various life stages, with the resistant population having higher generation mortality (0.22 vs 0.19). Conclusions: The study confirms the involvement of fitness costs associated with Bt resistance in P. gossypiella. Despite reduced reproductive fitness, the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence. Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs. The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed. [ABSTRACT FROM AUTHOR]

Abstract Background The pink bollworm, Pectinophora gossypiella (Saunders), is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-II® cotton plants in recent years due to the evolution of Bt resistance. The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops. Hence, the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant (Field-R) and susceptible (Lab-S) population. Results Prolonged larval duration (23.40 days in Field-R vs 18.80 days in Lab-S population), total life cycle (male = 50.00 vs 42.80 days; female = 53.60 vs 46.20 days), reduced fecundity (100.60 vs 154.20 eggs/female) and fertility (88.00 vs 138.00 fertile eggs/female) was observed. The demographic parameters indicated a significant reduction in the net reproductive rate (184.27 vs 276.72), innate capacity for increase in number (0.11 vs 0.15), finite rate of increase in number (1.12 vs 1.16 female progenies produced/female/day), weekly multiplication rate (2.16 vs 2.86), potential fecundity (545.06 vs 634.11 eggs), number of hypothetical F2 females (33 955.65 vs 76 572.41), but longer mean length of generation (47.54 vs 37.74 days) and population doubling time (6.30 vs 4.62 days) in Field-R compared with Lab-S population. A stage-specific life table demonstrated the differences in survival rates between susceptible and resistant populations at various life stages, with the resistant population having higher generation mortality (0.22 vs 0.19). Conclusions The study confirms the involvement of fitness costs associated with Bt resistance in P. gossypiella. Despite reduced reproductive fitness, the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence. Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs. The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed.

Pectinophora gossypiella one of the most destructive pests of Bt cotton. P. gossypiella gradually became a serious threat after gaining resistance to Bt toxin after 2 decade owing to which resulted in huge economic losses to the cotton growers. Present investigation was carried in order to study the most favourable temperature of P. gossypiella for its growth and development under various altering temperature regimes (20:30°C, 24:30°C,28:30°C, 20:35°C, 24:35°C, 28:35°C, 20:40°C, 24:40°C and 28:40°C) of Integrated Pest Management Laboratory, Department of Entomology, PAU, Ludhiana during cotton crop season 2022-23. Three models (linear and nonlinear) were used to estimate the relation between temperature and development rate of different instars and stages of P. gossypiella. The results revealed that duration of all larval instars and total larval duration were significantly short at an alternating temperature of 28:40°C. The pupal duration, adult longevity and total developmental period of male and female were recorded significantly low at the alternate temperature of 28:40°C. The fecundity and survivability (egg, larval and pupal)was significantly highest at 28:30°C, whereas the larval and pupal weights were significantly highest at an alternate temperature of 28:35°C. The correlation between developmental parameters and fecundity showed significant negative correlation. The survival of egg, larva and pupa showed non-significant negative correlation, whereas the larval and pupal weights show non-significant positive correlation with alternate temperatures. Stinner nonlinear and Inverse second order polynomial model provided more suitable temperature conditions for the development of P. gossypiella. [ABSTRACT FROM AUTHOR]

Sterile Insect Technique (SIT) is the right eco-friendly method to overcome the pink bollworm Pectinophora gossypiella (Saunder) menace. In SIT attractiveness of released moths to their natural counterpart is most important as such this ability was examined in our study. For this, newly emerged five virgin female gamma irradiated with 0–250 Gy were used. These females were placed inside small plastic vial provided with aeration and suspended inside the delta traps by providing 10% honey solution. Traps were placed in the field during evening. Moth catches in each trap were counted and removed daily and these observations continued up to 5 days. In a same manner irradiated males were released separately inside the field cage to know its attractiveness to virgin female. The results indicated that attraction of male moths to irradiated virgin females decreased significantly with increasing doses of radiation i.e., at 200 and 250 Gy. The number of males captured per female was greatest on day 2nd due to its peak sexual activity, i.e., 25.60, 23.05, 19.45, 14, 9.4 and 5.9 moths at 0, 50, 100, 150, 150, 200, and 250 Gy, respectively. Gamma radiation also affected the irradiated males to find their natural mates at a higher dose; however, the maximum number of 5.30, 5.95 and 5.10 irradiated male moths were attracted to the natural pheromone secreted by female moths at 50, 100 and 150 Gy respectively, compared to the 6.80 moths at 0 Gy. The results on attractiveness of irradiated male moths towards virgin female-baited traps were considered a good measure of male competitiveness.

Abstract Background Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) has become a potential pest of cotton by causing substantial yield losses around the world including Pakistan. Keeping in view the facts like limited research investigations, unavailability, and high cost of artificial diet’s constituents and their premixes, the present research investigations on the dietary aspect of P. gossypiella were conducted. The larvae of P. gossypiella were reared on different diets that were prepared using indigenous elements. The standard/laboratory diet comprised of wheat germ meal 34.5 g, casein 30.0 g, agar–agar 20.0 g, sucrose 10.0 g, brewer’s yeast 5.0 g, α-cellulose 1.0 g, potassium-sorbate1.5 g, niplagin 0.5 g, decavitamin 0.01 g, choline-chloride 0.06 g, maize-oil 3.30 g, honey 2.0 g, and water 730.0 mL. Alternatives to cotton bolls and wheat germ meal were okra seed sprouts, okra fruit, cottonseed meal, and okra seed meals, which were included in the study to introduce an efficient and economic mass-rearing system. Results The larval development completed in 19.68 d ± 0.05 d with a weight of 20.18 mg ± 0.20 mg at the fourth instar fed on the cottonseed meal-based diet instead of wheat germ meal based diet. On the same diet, 84.00% ± 4.00%, 17.24 mg ± 0.03 mg, and 7.76 d ± 0.06 d were recorded as pupae formation, pupal weight, and pupal duration, respectively. Adult emergence, 76.00% ± 1.00% was recorded from pupae collected from larvae raised on cottonseed meal-based diet. These male and female moths lived for 40.25 d ± 0.10 d, and 44.34 d ± 0.11 d, respectively. Females deposited 21.28 ± 0.04 eggs per day with the viability of 65.78% ± 0.14%. The larval mortality at the fourth instar was 37.20% ± 1.36% and malformed pupation of 12.00% ± 1.41% was recorded. Replacement of wheat germ meal with that of local meals (cottonseed and okra seed) in the standard laboratory diet has saved 463.80 to 467.10 PKR with 1.62 to 1.63 cost economic returns, respectively. Conclusion This research is of novel nature as it provides a concise and workable system for the economic and successful rearing of P. gossypiella under laboratory conditions.

An experiment was conducted at the Department of Cotton, Tamil Nadu Agricultural University, Coimbatore to evaluate the field efficacy of an egg parasitoid, Trichogrammatoidea bactrae Nagaraja through inundative releases against Pectinophora gossypiella (Saunders) in cotton for two successive field trials during Kharif 2021 and 22. The parasitisation efficacy of T. bactrae was tested in the cotton ecosystem and the results revealed that the parasitism on the eggs was found be on par with that observed with NSKE 5% concentration (24.63%), neem formulation 1500 ppm 1% concentration (24.10%), Pongamia extract 5% concentration (23.13%), Jatropha extract 5% concentration (23.93%) and were found the safest to T. bactrae. The emamectin benzoate 5 SG at 190g/ ha (19.49%) and clorantraniliprole 18.5 SC at 150 mL/ha (15.26%) were on par with each other. Results suggested that among the insecitcides tested emamectin benzoate 5 SG and chlorantraniliprole 18.5 SC were safer to T. bactrae and inundative release of T. bactrae can achieve sizeable control of P. gossypiella, hence it can be integrated with other components for IPM. [ABSTRACT FROM AUTHOR]

Background: Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) has become a potential pest of cotton by causing substantial yield losses around the world including Pakistan. Keeping in view the facts like limited research investigations, unavailability, and high cost of artificial diet's constituents and their premixes, the present research investigations on the dietary aspect of P. gossypiella were conducted. The larvae of P. gossypiella were reared on different diets that were prepared using indigenous elements. The standard/laboratory diet comprised of wheat germ meal 34.5 g, casein 30.0 g, agar–agar 20.0 g, sucrose 10.0 g, brewer's yeast 5.0 g, α-cellulose 1.0 g, potassium-sorbate1.5 g, niplagin 0.5 g, decavitamin 0.01 g, choline-chloride 0.06 g, maize-oil 3.30 g, honey 2.0 g, and water 730.0 mL. Alternatives to cotton bolls and wheat germ meal were okra seed sprouts, okra fruit, cottonseed meal, and okra seed meals, which were included in the study to introduce an efficient and economic mass-rearing system. Results: The larval development completed in 19.68 d ± 0.05 d with a weight of 20.18 mg ± 0.20 mg at the fourth instar fed on the cottonseed meal-based diet instead of wheat germ meal based diet. On the same diet, 84.00% ± 4.00%, 17.24 mg ± 0.03 mg, and 7.76 d ± 0.06 d were recorded as pupae formation, pupal weight, and pupal duration, respectively. Adult emergence, 76.00% ± 1.00% was recorded from pupae collected from larvae raised on cottonseed meal-based diet. These male and female moths lived for 40.25 d ± 0.10 d, and 44.34 d ± 0.11 d, respectively. Females deposited 21.28 ± 0.04 eggs per day with the viability of 65.78% ± 0.14%. The larval mortality at the fourth instar was 37.20% ± 1.36% and malformed pupation of 12.00% ± 1.41% was recorded. Replacement of wheat germ meal with that of local meals (cottonseed and okra seed) in the standard laboratory diet has saved 463.80 to 467.10 PKR with 1.62 to 1.63 cost economic returns, respectively. Conclusion: This research is of novel nature as it provides a concise and workable system for the economic and successful rearing of P. gossypiella under laboratory conditions. [ABSTRACT FROM AUTHOR]

A laboratory experiment was conducted to study the biology of pink bollworm Pectinophora gossypiella (Saunders) on cotton at four different temperature levels. It was found that males have a considerably shorter total life cycle duration on cotton at 35±1°C (29.5 days) followed by 30±1°C (37.2 days), 25±1°C (46.9 days) and highest at 20±1°C (50.8 days). Similarly, minimum total life cycle duration of female P. gossypiella was recorded at 35±1°C (30.2 days) followed by 30±1°C (38.0 days), 25±1°C (47.3 days) and maximum at 20±1°C (51.7 days). The highest fecundity was observed at 30±1°C (106.2) followed by 25±1°C (100.1), 35±1°C (60.1) and lowest at 20±1°C (55.2). Male as to female sex ratio was highest at 35±1°C (1:1.5) followed by 25±1°C (1:1.4), 30±1°C (1:1.3) and lowest at 20±1°C (1:1.2). These findings revealed that variation in temperature significantly influences the life cycle duration, fecundity and sex ratio of pink bollworms on cotton, with higher temperatures accelerating development and enhancing reproductive success. [ABSTRACT FROM AUTHOR]

Abstract Background The cryptic nature of pink bollworm Pectinophora gossypiella (Saunders) larvae enables its reduced vulnerability to insecticidal control. Further, the development of resistance against Bacillus thuringiensis (Bt) toxins posed a serious threat to transgenic cotton cultivation. This necessitated determining the critical timing of spray applications on the control effectiveness. This study assessed the influence of egg age (freshly laid vs. three-day-old) and the location of larvae (directly exposed to the insecticide residues on the boll rind vs. burrowed inside the bolls) on insecticide control efficacy. Results The results revealed a significant decrease in the ovicidal activity of tested insecticides with an increase in the age of eggs from one day old to three days old (paired t-test, P 80% mortality) than the larvae exposed after they had burrowed inside the bolls (

Abstract Background The emergence of pink bollworm (PBW), Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), in cotton due to Bt resistance and concealed feeding habit has created a need for alternative, eco-friendly, and cost-effective control methods. This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes (EPNs), Heterorhabditis indica, namely CICR-HI-CL and CICR-HI-MN, against PBW larvae and pupae under in-vitro conditions. Results The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd, 3rd, and 4th instar larvae, with median lethal dose (LD 50) values of 5.45, 4.45, and 4.60 infective juveniles (IJs) per larva, respectively. In case of pupal bioassay, both EPN strains demonstrated greater virulence when applied directly (LD 50 values: 29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN, respectively) compared to soil application (147.84 and 272.38 IJs per pupa). Both EPN strains successfully penetrated and reproduced on 4th instar larvae, resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva. Conclusion The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H. indica (CICR-HI-CL and CICR-HI-MN) against PBW, a dreaded pest of cotton. Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply, sustain and perpetuate on larval and pupal stages of PBW. The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate. The soil-dwelling life stages viz., last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H. indica for sustainable management of PBW in the cotton ecosystem. However, before taking these EPN strains to field for managing PBW, detailed studies investigating their biocontrol potential against PBW under field conditions are needed.

Background: The cryptic nature of pink bollworm Pectinophora gossypiella (Saunders) larvae enables its reduced vulnerability to insecticidal control. Further, the development of resistance against Bacillus thuringiensis (Bt) toxins posed a serious threat to transgenic cotton cultivation. This necessitated determining the critical timing of spray applications on the control effectiveness. This study assessed the influence of egg age (freshly laid vs. three-day-old) and the location of larvae (directly exposed to the insecticide residues on the boll rind vs. burrowed inside the bolls) on insecticide control efficacy. Results: The results revealed a significant decrease in the ovicidal activity of tested insecticides with an increase in the age of eggs from one day old to three days old (paired t-test, P < 0.05). The larvae directly exposed to the insecticide residues on the boll rind were more susceptible (> 80% mortality) than the larvae exposed after they had burrowed inside the bolls (< 49% mortality). The inhibitory effects of tested insecticides on developmental biology were more pronounced in the experiment on pre-larval release insecticide treatment compared with insecticide treatment given post-larval release and entry inside the bolls. Conclusion: Egg age influences the insecticide susceptibility, as does the larval location, directly exposed vs burrowed inside the bolls. Older eggs and the larvae that had burrowed inside the green bolls of cotton were relatively less susceptible to the insecticide treatments. The toxic effects of insecticides on egg and larval stages were primarily ephemeral. These findings are significant for devising a comprehensive strategy for pink bollworm management on a sustainable basis. [ABSTRACT FROM AUTHOR]

Population fluctuations of Aphis gossypii, Chloridea virescens, Anthonomus vestitus, Dysdercus peruvianus and Pectinophora gossypiella, besides their natural enemies were studied during the entire phenological period of a Tangüis cotton crop at La Molina (Lima), using three sampling techniques: direct plant evaluation, plant shake falls and pitfall traps. A. gossypii was the most abundant pest, being more important in the vegetative development, followed by D. peruvianus and P. gossypiella, both with greater importance in the fructification stage. Predatory insects and spiders were recorded during the whole crop period, where the most frequent were, in predatory insects Hippodamia convergens, Hyalochloria denticornis and Rhinacloa forticornis, and in spiders Misumenops sp. morpho 1, Zelotes laetus and Theridion volubile. Parasitoidism was low or scarce in most of the pests, highlighting Lysiphlebus testaceipes as A. gossypii parasitoid due to its abundance in the vegetative development of the cotton field. [ABSTRACT FROM AUTHOR]

The pink bollworm, Pectinophora gossypiella (Saund.) is an important pest that causes severe economic loss for cotton crop. The potent bioactive properties of three tested compounds; the two IGRs compounds; Dimilin (Diflubenzuron) and Nomolt (Teflubenzuron), and the bio-pesticide compound Emacte (Emamectin benzoate); were tested against two different ages of P. gossypiella eggs under laboratory conditions of 26±1°C and 70±5% RH. Results revealed that older eggs of P. gossypiella are more susceptible to pesticides than the younger ones where LC50 values were 155.4, 185.85, and 1.95 ppm. for 0-1-day-old eggs, while decreased to 81.42, 103.42, and 1.30 ppm, for 2-3 days-old eggs in Dimilin, Nomolt, and Emacte treatments, respectively. The incubation periods for eggs were prolonged as a result of the treatments, in comparison to the untreated check. In addition, the estimated developmental periods for the immature stages increased to 19.6, 17.9 and15.85 days for larva and 12.5, 11.8, and 9.76 days for pupa, in treatment of 0-1 day old eggs and to 20.2, 18.8, and 16.9 days for larva and 13.6, 11.98 and 10.36 days for pupa in treatment of 2-3 days old eggs in Dimilin, Nomolt and Emacte treatments respectively, compared to 14.55 days for larval stage and 8.03 days for pupal stage in the untreated. The present study noted also, light changes in the levels of the total protein, carbohydrate and chitin composition during embryogenesis for P. gossypiella eggs as a result of treatments in comparison to the untreated. [ABSTRACT FROM AUTHOR]

Background: The emergence of pink bollworm (PBW), Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), in cotton due to Bt resistance and concealed feeding habit has created a need for alternative, eco-friendly, and cost-effective control methods. This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes (EPNs), Heterorhabditis indica, namely CICR-HI-CL and CICR-HI-MN, against PBW larvae and pupae under in-vitro conditions. Results: The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd, 3rd, and 4th instar larvae, with median lethal dose (LD50) values of 5.45, 4.45, and 4.60 infective juveniles (IJs) per larva, respectively. In case of pupal bioassay, both EPN strains demonstrated greater virulence when applied directly (LD50 values: 29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN, respectively) compared to soil application (147.84 and 272.38 IJs per pupa). Both EPN strains successfully penetrated and reproduced on 4th instar larvae, resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva. Conclusion: The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H. indica (CICR-HI-CL and CICR-HI-MN) against PBW, a dreaded pest of cotton. Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply, sustain and perpetuate on larval and pupal stages of PBW. The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate. The soil-dwelling life stages viz., last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H. indica for sustainable management of PBW in the cotton ecosystem. However, before taking these EPN strains to field for managing PBW, detailed studies investigating their biocontrol potential against PBW under field conditions are needed. [ABSTRACT FROM AUTHOR]

A laboratory experiment was conducted to study the biology of pink bollworm Pectinophora gossypiella (Saunders) on cotton at four different temperature levels. It was found that males have a considerably shorter total life cycle duration on cotton at 35±1°C (29.5 days) followed by 30±1°C (37.2 days), 25±1°C (46.9 days) and highest at 20±1°C (50.8 days). Similarly, minimum total life cycle duration of female P. gossypiella was recorded at 35±1°C (30.2 days) followed by 30±1°C (38.0 days), 25±1°C (47.3 days) and maximum at 20±1°C (51.7 days). The highest fecundity was observed at 30±1°C (106.2) followed by 25±1°C (100.1), 35±1°C (60.1) and lowest at 20±1°C (55.2). Male as to female sex ratio was highest at 35±1°C (1:1.5) followed by 25±1°C (1:1.4), 30±1°C (1:1.3) and lowest at 20±1°C (1:1.2). These findings revealed that variation in temperature significantly influences the life cycle duration, fecundity and sex ratio of pink bollworms on cotton, with higher temperatures accelerating development and enhancing reproductive success.

Abstract Background During field surveillance in Gujarat, India, in 2009, scientists found that pink bollworm was surviving in the first generation of Bollgard cotton, which contains a single protein. This survival was observed in four districts of Gujarat. From 2012 to 2014, surveys revealed that pink bollworm larvae had higher survival rates on Bollgard II cotton in Amreli and Bhavnagar districts. In 2016, a pink bollworm outbreak in Maharashtra caused significant losses in cotton production, leading to damage, yield losses, and increased management costs in several regions. The objective of the present study was to determine the reaction of Pectinophora gossypiella to Cry1Ac and Cry2Ab toxins. Results Neonates of P. gossypiella collected from six distinct locations in Vidarbha were subjected to seven different concentrations of Cry1Ac. The highest LC50 value was recorded in the population collection of Yavatmal (1.362 μg/ml diet) but the lowest LC50 value of 0.600 μg/ml diet in Buldana population. The highest MIC50 value was recorded in the population collected from Yavatmal (0.743 μg/ml diet) and the lowest MIC50 value of 0.413 μg/ml diet in the Buldana population (0.431 μg/ml diet). The highest IC50 value was recorded in the population collected from Yavatmal (0.303 μg/ml diet) but the lowest IC50 value of 0.127 μg/ml diet in the Buldana population. Neonates of P. gossypiella collected from six different locations in Vidarbha were exposed to seven different concentrations (9.0, 3.0, 1.0, 0.333, 0.111, 0.037 and 0.012 for Cry1Ac and 27.0, 9.0, 3.0, 1.0, 0.333, 0.111 and 0.037 μg/ml for Cry2Ab) which revealed that the Yavatmal population had the highest LC50 value of 94.294 μg/ml diet and the lowest LC50 value was recorded in the Amravati population (42.144 μg/ml diet). The highest MIC50 value of 27.258 μg/ml diet was recorded in Buldana population, but the lowest MIC50 value was recorded in the Amravati population (12.881 μg/ml diet). The highest IC50 value of 3.209 μg/ml diet was observed in Yavatmal population, and the lowest one was recorded in the Amravati population (1.574 μg/ml diet). Conclusions According to the LC50 values, all of the P. gossypiella populations in Vidarbha were extremely insensitive and had field-evolved resistance to the Bt proteins found in the transgenic cotton varieties of Bollgard II.

Pectinophora gossypiella (Saunders) is a potential threat for the successful cultivation of cotton all over the world. Despite the use of modern management strategies, the damage caused by this pest is increasing. The repeated exposure of this pest to Bacillus thuringenisis (Bt) crops resulted in resistance development, which has threatened the continued success of Bt cotton cultivation. Salicylic acid has been reported to enhance the efficiency of crops. The present study was carried out to determine the effect of salicylic acid on the oviposition (pre-oviposition and post-oviposition time) and feeding behavior (pre-feeding time and post-feeding time) of pink bollworm larvae in two cotton varieties, i.e., CIM-70 and NIAB-78. In the first experiment, leaves and bolls treated with different concentrations of salicylic acid were kept in an oviposition chamber and adults were released in a chamber with a ratio of 5:5 males to females, respectively. The experiment was performed following a Completely Randomized Design (CRD) with three replications and six concentrations of salicylic acid (0, 10, 20, 40, 80, and 160 ppm). In a second complementary experiment, salicylic acid was evaluated against feeding behavior, i.e., larval duration, pre-feeding time, feeding time, post-feeding time, and percentage mortality of pink bollworm. In both experiments, the results revealed that the application of salicylic acid at a maximum concentration was effective against the oviposition and feeding of pink bollworm only in the NIAB-78 cultivar. It is concluded that salicylic acid has the potential to reduce pink bollworm risks, and the present investigation will help researchers as well as farmers plan for the timely sustainable management of pink bollworm. [ABSTRACT FROM AUTHOR]

Abstract 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.

Background: During field surveillance in Gujarat, India, in 2009, scientists found that pink bollworm was surviving in the first generation of Bollgard cotton, which contains a single protein. This survival was observed in four districts of Gujarat. From 2012 to 2014, surveys revealed that pink bollworm larvae had higher survival rates on Bollgard II cotton in Amreli and Bhavnagar districts. In 2016, a pink bollworm outbreak in Maharashtra caused significant losses in cotton production, leading to damage, yield losses, and increased management costs in several regions. The objective of the present study was to determine the reaction of Pectinophora gossypiella to Cry1Ac and Cry2Ab toxins. Results: Neonates of P. gossypiella collected from six distinct locations in Vidarbha were subjected to seven different concentrations of Cry1Ac. The highest LC50 value was recorded in the population collection of Yavatmal (1.362 μg/ml diet) but the lowest LC50 value of 0.600 μg/ml diet in Buldana population. The highest MIC50 value was recorded in the population collected from Yavatmal (0.743 μg/ml diet) and the lowest MIC50 value of 0.413 μg/ml diet in the Buldana population (0.431 μg/ml diet). The highest IC50 value was recorded in the population collected from Yavatmal (0.303 μg/ml diet) but the lowest IC50 value of 0.127 μg/ml diet in the Buldana population. Neonates of P. gossypiella collected from six different locations in Vidarbha were exposed to seven different concentrations (9.0, 3.0, 1.0, 0.333, 0.111, 0.037 and 0.012 for Cry1Ac and 27.0, 9.0, 3.0, 1.0, 0.333, 0.111 and 0.037 μg/ml for Cry2Ab) which revealed that the Yavatmal population had the highest LC50 value of 94.294 μg/ml diet and the lowest LC50 value was recorded in the Amravati population (42.144 μg/ml diet). The highest MIC50 value of 27.258 μg/ml diet was recorded in Buldana population, but the lowest MIC50 value was recorded in the Amravati population (12.881 μg/ml diet). The highest IC50 value of 3.209 μg/ml diet was observed in Yavatmal population, and the lowest one was recorded in the Amravati population (1.574 μg/ml diet). Conclusions: According to the LC50 values, all of the P. gossypiella populations in Vidarbha were extremely insensitive and had field-evolved resistance to the Bt proteins found in the transgenic cotton varieties of Bollgard II. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is an important pest of cotton worldwide; causing significant economic loss to cotton growers. Its control under field condition is difficult, as it remains inside the boll and feeds internally. Therefore, under this study we have evaluated different insecticides viz., Quinalphos 25% EC, Profenofos 50% EC, Thiodicarb 75% WP, Chlorantraniliprole 18.5% SC, Spinosad 45% SC, Neem oil (0.3% W/W), Cypermethrin 25% EC, Triazophos 40% EC, Deltamethrin 2.8% EC and the combination of Profenofos 40% + Cypermethrin 4% EC and Deltamethrin 1% + Triazophos 35% EC for the management of P. gossypiella in cotton under rainfed conditions. The results revealed that combination of Profenofos 40% + Cypermethrin 4% EC showed most effective and offered lowest number of exit holes (0.3 to 0.5), mines on epicarp (2.0 to 7.0), larvae/plant (0.3 to 1.0) and per cent locule damage (1.3 to 7.3%) in green bolls as compared to individual formulations. Among individual formulations, Cypermethrin 25% EC effectively controlled pink bollworm larval damage (0.3 to 1.1 exit holes, 3.3 to 4.0 mines on epicarp, 0.9 to 1.7 larvae and 1.3 to 13.0% locule damage in green bolls after 10 days of spray) as compared to other treatments. Further, maximum seed cotton yield was recorded (11.6 to 12.04 q/ha) in Profenofos 40% + Cypermethrin 4% EC treated fields. The integration of these insecticide molecules proved to be effective in the management of pink bollworm under field conditions. [ABSTRACT FROM AUTHOR]

The pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), is a major global pest of cotton. Current management practices include chemical insecticides, cultural strategies, sterile insect releases, and transgenic cotton producing crystalline (Cry) protein toxins of the bacterium Bacillus thuringiensis (Bt). These strategies have contributed to the eradication of P. gossypiella from the cotton-growing areas of the United States and northern Mexico. However, this pest has evolved resistance to Bt cotton in Asia, where it remains a critical pest, and the benefits of using transgenic Bt crops have been lost. A complete annotated reference genome is needed to improve global Bt resistance management of the pink bollworm. We generated the first chromosome-level genome assembly for pink bollworm from a Bt-susceptible laboratory strain (APHIS-S) using PacBio continuous long reads for contig generation, Illumina Hi-C for scaffolding, and Illumina whole-genome re-sequencing for error correction. The pseudo-haploid assembly consists of 29 autosomes and the Z sex chromosome. The assembly exceeds the minimum Earth BioGenome Project quality standards, has a low error rate, is highly contiguous at both the contig and scaffold levels (L/N50 of 18/8.26 MB and 14/16.44 MB, respectively), and is complete, with 98.6% of lepidopteran single-copy orthologs represented without duplication. The genome was annotated with 50% repeat content and 14,107 protein-coding genes, further assigned to 41,666 functional annotations. This assembly represents the first publicly available complete annotated genome of pink bollworm and will serve as the foundation for advancing molecular genetics of this important pest species. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate how irradiated hosts affected the mass rearing of the ectoparasitoid Bracon brevicornis Wesmael. To investigate the development of B. brevicornis stages on three hosts; full-grown larvae of Pectinophora gossypiella, Galleria mellonella, and Spodoptera litoralis were irradiated with 100, 200, and 300 Gy. The use of 100Gy in irradiating P. gossypiella and G. mellonella produced utilization in promoting parasitism and adult emergence of B. brevicornis, with parasitism percentages of 77.00% and 80.00% for P. gossypiella and G. mellonella, respectively, when compared to control larvae or other irradiated doses. The results of the biochemical experiments showed that G. mellonella > P. gossypiella > S. littoralis was the order of the insects in terms of total protein, lipids, and glucose. It could be concluded that using 100Gy irradiated P. gossypiella and G. mellonella larvae would aid in improving B. brevicornis mass production and the effectiveness of B. brevicornis. [ABSTRACT FROM AUTHOR]

Simple Summary: The pink bollworm, Pectinophora gossypiella, is one of the most damaging pests of cotton worldwide. Cotton has been genetically engineered to produce insect-killing proteins from the bacterium Bacillus thuringiensis (Bt) to control major lepidopteran pests, including the pink bollworm. The Bt proteins in genetically engineered crops are not toxic to people, other vertebrates, or most beneficial insects. Advantages of Bt crops can include pest suppression, improved yields, increased farmer profits, and decreased use of conventional insecticides. In the United States, Bt cotton, sterile moth releases, and other tactics were used to eradicate the pink bollworm. For more than 20 years, Bt cotton has been effective against pink bollworm in China. However, the benefits of Bt crops are reduced when pests evolve resistance, as exemplified by pink bollworm resistance to Bt cotton in India. For each of the two Bt proteins used widely in Bt cotton, the genetic basis of resistance is similar between resistance selected in the lab versus the field, regardless of the country of origin. The results suggest that lab selection can be useful for identifying genes likely to be important in field-evolved resistance to Bt crops and that differences in management practices among countries caused different outcomes. Transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) control some important insect pests. However, evolution of resistance by pests reduces the efficacy of Bt crops. Here we review resistance to Bt cotton in the pink bollworm, Pectinophora gossypiella, one of the world's most damaging pests of cotton. Field outcomes with Bt cotton and pink bollworm during the past quarter century differ markedly among the world's top three cotton-producing countries: practical resistance in India, sustained susceptibility in China, and eradication of this invasive lepidopteran pest from the United States achieved with Bt cotton and other tactics. We compared the molecular genetic basis of pink bollworm resistance between lab-selected strains from the U.S. and China and field-selected populations from India for two Bt proteins (Cry1Ac and Cry2Ab) produced in widely adopted Bt cotton. Both lab- and field-selected resistance are associated with mutations affecting the cadherin protein PgCad1 for Cry1Ac and the ATP-binding cassette transporter protein PgABCA2 for Cry2Ab. The results imply lab selection is useful for identifying genes important in field-evolved resistance to Bt crops, but not necessarily the specific mutations in those genes. The results also suggest that differences in management practices, rather than genetic constraints, caused the strikingly different outcomes among countries. [ABSTRACT FROM AUTHOR]

Simple Summary: Bt (Cry1Ac) cotton has been commercialized in China since 1997. Two tactics have mainly been used in targeted pest resistance management for small farmers. The first is the use of natural refuges composed of corn, soybeans, vegetables, peanuts, and other crops to delay the development of the resistance of multi-host crop pests such as the cotton bollworm (Helicoverpa armigera) to Bt cotton. The second is to use the offspring of F2 generation hybrids (Bt and non-Bt cotton hybrids) to produce a 25% seed mix refuge formed by non-Bt cotton, further delaying the evolution of resistance of single cotton-eating target pests such as the pink bollworm (Pectinophora gossypiella). The 25-year production practice has demonstrated that this dual strategy of Bt cotton resistance management in China has been very successful to date, with no failures observed in lepidopteran pest control in the production process. China is one of the major cotton producers globally with small farmers. Lepidopteran pests have always been the main factor affecting cotton production. To reduce the occurrence of and damage caused by lepidopteran pests, China has employed a pest control method focused on planting Bt (Cry1Ac) cotton since 1997. Chinese resistance management tactics for the main target pests, the cotton bollworm and pink bollworm, were also implemented. For polyphagous (multiple hosts) and migratory pests such as the cotton bollworm (Helicoverpa armigera), the "natural refuge" strategy, consisting of non-Bt crops such as corn, soybean, vegetables, peanuts, and other host crops, was adopted in the Yellow River Region (YRR) and Northwest Region (NR). For a single host and weak migration ability pest, such as the pink bollworm (Pectinophora gossypiella), the seed mix refuge strategy yields a random mixture within fields of 25% non-Bt cotton by sowing second-generation (F2) seeds. According to field monitoring results for more than 20 years in China, practical resistance (Bt cotton failure) of target pests was avoided, and there were no cases of Bt (Cry1Ac) failure of pest control in cotton production. This indicated that this Chinese resistance management strategy was very successful. The Chinese government has decided to commercialize Bt corn, which will inevitably reduce the role of natural refuges; therefore, this paper also discusses adjustments and future directions of cotton pest resistance management strategies. [ABSTRACT FROM AUTHOR]

Indian populations of the Pink Bollworm (PBW) are resistant to Bt (Bacillus thuringiensis) cotton hybrids containing Cry1Ac and Cry2Ab genes. Segregation of these Cry genes in F1 hybrids could subject PBW to sublethal concentrations. Moreover, planting hybrids with varying zygosities of Cry genes could produce diverse segregation patterns and expose PBW populations to highly variable toxin concentrations. This could potentially promote the rate of resistance development. Therefore, we studied the segregation patterns of Cry genes in different commercial Bt hybrids cultivated in India. Results showed that two hybrids segregated according to the Mendelian mono-hybrid ratio, three segregated according to the Mendelian di-hybrid ratio, and one showed a mixed segregation pattern. The assortment of seeds containing Cry genes varied between bolls of the same hybrid. In India, different Bt cotton hybrids are cultivated in small patches next to each other, exposing PBW populations to sublethal doses and wide variations in the occurrence of Cry genes. It is necessary to avoid segregation of Cry genes in the seeds produced by F1 hybrids. This study recommends using Bt parents homozygous for Cry genes in commercial Bt cotton hybrid development. This breeding strategy could be effective for similar transgenic crop hybrids as well. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at Regional Agricultural Research Station, Lam, Guntur, Andhra Pradesh during kharif, 2018 to evaluate the bio-efficacy of certain insecticides against Pectinophora gossypiella. The treatments under study were emamectin benzoate, flubendiamide, chlorantraniliprole, chlorantraniliprole + lambda cyhalothrin, deltamethrin, NSKE 5%, profenophos and cypermethrin along with one untreated control. Three sprays were given at 10 days interval and the data on larval population was collected at three, seven and ten days after spraying. The results of three sprays revealed that chlorantraniliprole + lambda cyhalothrin was effective in the control of P. gossypiella, which recorded 78.54, 85.24 and 94.36 per cent reduction larval population for 20 bolls over control at first, second and third sprays respectively followed by cypermethrin with per cent reduction of 74.03, 83.52 and 90.87 over control at first, second and third sprays respectively. Chlorantraniliprole + lambda cyhalothrin recorded highest number of good opened bolls per plant and seed cotton yield of 42.33 and 3786 kg ha-1, respectively followed by cypermethrin 25 EC (40.93 and 3662 kg ha-1) when compared to untreated control (22.40 and 2304 kg ha-1). [ABSTRACT FROM AUTHOR]

Aphis craccivora (Hemiptera) is a major sucking pest of cowpea. Aphis craccivora is also known as the cowpea aphid. Pectinophora gossypiella (Lepidoptera) is an oligophagous chewing pest of cotton, commonly known as the pink bollworm. These insects cause severe losses in the production of cowpeas and cotton, respectively. The α-amylases of these insects were characterized to shed light on the complement of amylases of these two insects from different orders. The α-amylases of A. craccivora and P. gossypiella were found highly active at pH 8 and 9 respectively. At 37 °C, the activities of α-amylase in P. gossypiella and A. craccivora were 1.720.078 mg/min/ml and 0.36430.007 mg/min/ml, respectively. As calculated by Lineweaver–Burk plots, the Km values of A. craccivora and P. gossypiella were 10.5 ± 1.5 µM and 27.7 ± 6.5 µM respectively. The Vmax value of A. craccivora amylase was 5 ± 0 mM/min/µg and 21.8 ± 4 µM/min/µg for P. gossypiella. Electrophoretic visualization indicated 6 isoforms of α-amylase in both the 3rd and 4th instar larvae of P. gossypiella. In A. craccivora, 3 isoforms were observed. The molecular weight of P. gossypiella amylases was around 30 to 294 kDa and A. craccivora amylases were around 77 to 160 kDa. Fe and Mn activated amylase activity in P. gossypiella, while Co and Zn were inhibitory. In A. craccivora, Mn activated the amylase activity. The biochemical and electrophoretic characterizations of the amylases of these insects may significantly contribute to the understanding of the physiology of these chewing and sucking pests. The insights may be exploited for amylase inhibitor-based pest control strategies against this differently-feeding insect. [ABSTRACT FROM AUTHOR]

Pectinophora gossypiella (Saunders) is a potential threat for the successful cultivation of cotton all over the world. Despite the use of modern management strategies, the damage caused by this pest is increasing. The repeated exposure of this pest to Bacillus thuringenisis (Bt) crops resulted in resistance development, which has threatened the continued success of Bt cotton cultivation. Salicylic acid has been reported to enhance the efficiency of crops. The present study was carried out to determine the effect of salicylic acid on the oviposition (pre-oviposition and post-oviposition time) and feeding behavior (pre-feeding time and post-feeding time) of pink bollworm larvae in two cotton varieties, i.e., CIM-70 and NIAB-78. In the first experiment, leaves and bolls treated with different concentrations of salicylic acid were kept in an oviposition chamber and adults were released in a chamber with a ratio of 5:5 males to females, respectively. The experiment was performed following a Completely Randomized Design (CRD) with three replications and six concentrations of salicylic acid (0, 10, 20, 40, 80, and 160 ppm). In a second complementary experiment, salicylic acid was evaluated against feeding behavior, i.e., larval duration, pre-feeding time, feeding time, post-feeding time, and percentage mortality of pink bollworm. In both experiments, the results revealed that the application of salicylic acid at a maximum concentration was effective against the oviposition and feeding of pink bollworm only in the NIAB-78 cultivar. It is concluded that salicylic acid has the potential to reduce pink bollworm risks, and the present investigation will help researchers as well as farmers plan for the timely sustainable management of pink bollworm.

The pink bollworm, Pectinophora gossypiella, (Saunders) (Lepidoptera: Gelechiidae) considers as one of the world's most invasive insects, is a voracious lepidopteran pest of cotton. To control this insect pest and increase crop yield, chemical pesticides was mainly used and that caused resistant population and side effects for human and environment. Therefore, there is a need to increase of alternative methods such as the biological control. During the current study, five fungi isolates, one of Beauveria bassiana (AUMC 9896) and four of Metarhizium anisopliae (M1, M2, M3 &M4) were evaluated against the eggs, new hatched larvae, and pupa of P. gossypiella under laboratory conditions. Bioassay was performed using spores suspension concentrations (1.0 × 106, 1.0× 107 and 1.0×108 spores/ml). Results showed that B. bassiana (AUMC 9896) proved to be more toxicity than M. anisopliae isolates as depicted by the calculated LC50 values on all treated stages, egg, larva, and pupa. On the other hand, the highest egg and pupal mortality percentages were recorded to B. bassiana (76.7 and 80.0%), respectively, at the same concentration (1×108 spores/ml). Whereas the isolate M. anisopliae (M4) showed the least one (23.3 and 46.6 %). Also, M. anisopliae isolates (M1 & M4) had recorded the highest value of larval mortality (86.7%). Thus, it can be concluded that the isolates B. bassiana (AUMC 9896 and M1) were strong pathogenicity while the isolates (M3&M4) were moderate and (M2) was showed low pathogenicity. [ABSTRACT FROM AUTHOR]

The present study on biology of pink bollworm on two modified artificial diets separately was carried out in the Toxicology laboratory, Department of Agriculture Entomology, Post Graduate Institute, Dr PDKV, Akola during October to February 2018-19 and 2019-20 with controlled conditions such as 25±2oC temperature 65±5% RH and photoperiod of 14:10 h light: dark. Two modified artificial diets were prepared separately with some modifications in the ingredients, pink bollworm larvae are reared on two above said modified artificial diets and observations were recorded on different biological parameters like egg incubation period (days), larval period (days), pupal period (days), adult emergence (%), adult male and female longevity(days), preoviposition period (days), oviposition (days), fecundity(no of eggs per female), total life cycle(days) and on morphometry of different stages pink bollworm like egg, first, second, third and fourth instar larval stages, male and female pupa and male and female adult moth. Our results indicated that pink bollworm has four larval instars with mean larval duration of 18.60±0.54 days in modified artificial diet 1 and 17.72±0.36 days in modified artificial diet 2 population respectively. Total life cycle from egg to adult was 46.74±0.31 and 54.71±0.62 days in modified artificial diet 1 and modified artificial diet 2 population respectively. Total life cycle of pink bollworm was completed somewhat earlier in in modified artificial diet 1 in comparison to modified artificial diet 2. Our results showed that there was only a little difference in the biology of pink bollworm on both modified artificial diets, and hence both modified artificial diets can be used for laboratory rearing purposes. [ABSTRACT FROM AUTHOR]

The effect of four cultivated species of cotton on the oviposition behaviour and/or preference of pink bollworm, Pectinophora gossypiella was studied under laboratory conditions. Blends of volatile organic compounds from squares of all four species of cotton (Gossypium arboreum , G. herbaceum , G. hirsutum , G. barbadense) were identified using gas chromatography-mass spectroscopy (GC-MS). Differences were observed across the species with respect to the relative proportion of identified compounds, viz., pinene, carene, caryophyllene, humulene and γ terpinene. In order to evaluate the ovipositional preference of pink bollworm, a series of no-choice and choice experiments were conducted using square extract, artificial blend-treated muslin cloth and cotton twig as substrate for oviposition. All four species of cotton had differences in the volatile blend composition that were reflected in the mean number of eggs laid under no-choice and choice experiments. A substantially higher number of eggs was laid on cotton twig under both no-choice and choice experiments than on square extract and artificial blend treatments. In both no-choice and choice experiments G. herbaceum was found to be the least preferred for egg laying compared to the other three species. [ABSTRACT FROM AUTHOR]

BACKGROUND: Transgenic crops that make insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized management of some pests. However, evolution of resistance to Bt toxins by pests diminishes the efficacy of Bt crops. Resistance to crystalline (Cry) Bt toxins has spurred adoption of crops genetically engineered to produce the Bt vegetative insecticidal protein Vip3Aa. Here we used laboratory diet bioassays to evaluate responses to Vip3Aa by pink bollworm (Pectinophora gossypiella), one of the world's most damaging pests of cotton. RESULTS: Against pink bollworm larvae susceptible to Cry toxins, Vip3Aa was less potent than Cry1Ac or Cry2Ab. Conversely, Vip3Aa was more potent than Cry1Ac or Cry2Ab against laboratory strains highly resistant to those Cry toxins. Five Cry‐susceptible field populations were less susceptible to Vip3Aa than a Cry‐susceptible laboratory strain (APHIS‐S). Relative to APHIS‐S, significant resistance to Vip3Aa did not occur in strains selected in the laboratory for > 700‐fold resistance to Cry1Ac or both Cry1Ac and Cry2Ab. CONCLUSIONS: Resistance to Cry1Ac and Cry2Ab did not cause strong cross‐resistance to Vip3Aa in pink bollworm, which is consistent with predictions based on the lack of shared midgut receptors between these toxins and previous results from other lepidopterans. Comparison of the Bt toxin concentration in plants relative to the median lethal concentration (LC50) from bioassays may be useful for estimating efficacy. The moderate potency of Vip3Aa against Cry1Ac‐ and Cry2Ab‐resistant and susceptible pink bollworm larvae suggests that Bt cotton producing this toxin together with novel Cry toxins might be useful as one component of integrated pest management. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is the most destructive insect-pest among the bollworm complex of cotton in the recent epoch. The global downfall in cotton production is attributed to the increasing resistance developed in bollworms especially the P. gossypiella. An efficient mass production system is a pre-requisite to address such yield losses. Inadequate historical investigations lead to initiate the present study. Locally available and cost effective materials were evaluated to find their impact on the adult biology of P. gossypiella under laboratory condition maintained at 27 ± 2 °C, 60 ± 10% relative humidity, and 14:10 (L: D) photoperiod. The principle parameters of P. gossypiella biology included pre-oviposition, oviposition, post oviposition, female and male life span, fecundity, and average fecundity. Results revealed that the moths started to deposit eggs within 2.33 ± 0.33 to 3.00 ± 0.00 days. The female moths laid 238.00 ± 3.79 eggs, spent 13.67 ± 0.33 and 6.67 ± 0.67 days as oviposition and post-oviposition period when muslin cloth (black) was used as oviposition substrate. The male and female completed their life span in 49.11 ± 0.04 and 59.15 ± 0.03 days respectively. The research findings lead to the conclusion that muslin cloth (black) could be used as a substitute of Gouche sheets for oviposition among the indigenous substrates. Hence, the use of muslin cloth (black) as oviposition substrates can contribute towards an efficient and cost effective rearing system for Pectinophora gossypiella (Saunders) (Gelechiidae: Lepidoptera) with special emphasis on fecundity. [ABSTRACT FROM AUTHOR]

Cotton is one of the major commercial crops cultivated in India. One constraint limiting the potential yield in cotton is due to the bollworm complex, among which pink bollworm (PBW), Pectinophora gossypiella (Saunders), is major. To reduce this impact of PBW, farmers have opted for chemical insecticides to manage the pest. Indiscriminate use of these insecticides has led to the problem of resistance. Hence continuous monitoring is a must to keep check on the changing status and trends in the resistance. In order to conduct laboratory studies, a uniform population of sufficient size, producing the insect in high numbers and throughout the year, is required. Hence, a semi-synthetic diet will greatly help in maintaining such populations in the laboratory. The protocol followed for the rearing has resulted in increased larval and pupal weights which depict the suitability of the semi-synthetic diet as well as the efficiency of the rearing technique. This study on the biology of PBW has revealed that the rearing protocol on semi-synthetic diet is ideal, and this has enables us to obtain maximum recovery (less mortality) in a short period of time under laboratory conditions. [ABSTRACT FROM AUTHOR]

The susceptibility of three different field strains collected from Beni Suef, Monufia and Beheira Governorates of the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) to chlorpyrifos, profenofos, alpha-cypermethrin, esfenvalerate, lambda-cyhalothrin, emamectin benzoate, spinetoram and spinosad was evaluated by bioassay tests in Central Agricultural Pesticides Laboratory. The results indicated that spinosad was the most toxic to all strains studied and in all tested seasons, 2017, 2018 and 2019. Its LC50 values were 31.6, 40.0 and 67.2 mg/L in 2017, 60.0, 69.4 and 47.7 mg/L in 2018 and 42.0, 27.8 and 20.0 mg/L in 2019 of Monufia, Beheira and Beni Suef, respectively. Both chloropyrifos and alphacypermethrin were the lowest toxic to the three strains investigated. [ABSTRACT FROM AUTHOR]

Abstract Cotton is an important cash crop in many developing countries, supporting the livelihoods of millions of poor people. Crop productivity has increased globally since the introduction of Bt cotton. Despite the Bt cotton area expanding year after year, most farmers are not getting guaranteed yields due to the high incidence of Pink bollworm (PBW). The Integrated Pest Management tactics including, the use of pheromone traps, manual destruction of rosette flowers, the application of biopesticides (Azadirachtin 1500 ppm) and synthetic insecticide (Thiodicarb 75% WP) were evaluated against cotton PBW farmer’s field conditions in Southern Telangana Zone of Telangana state, India during 2018–19, 2019–20, and 2020–21. The observations on incidence and percentage of reduction of PBW, extension gap, technology gap and technology index, were worked out in farmer’s field and demonstration field. During three growing seasons, the mean PBW infestation of cotton crops ranged between 38.3 ± 5.87, 40 ± 8.34, and 40.4 ± 3.80, respectively. In the present study, the activity of PBW adults were started at initial square formation to flowering stage (i.e. 55–60 days after sowing) and more number of adults was trapped post boll picking during all the observed years. During the studied years, the mean pest population reduction due to azadirachtin and thiodicarb application ranged from 30.37 to 43.71 and 35.14 to 53.78%, respectively. The benefit-cost ratio analysis shows that the adoption of IPM practices gives more benefit per rupee invested, i.e. 1.35, 2.07, and 1.51, compared to farmer’s practice 1.11, 1.71, and 1.36, respectively during 2018–19, 2019–20, and 2020–21. Similarly, the technology gap, extension gap, and technology index in the demonstration field ranged from 2 to 13.09, 1.02 to 3.9, and 6.67 to 43.63%, respectively. The lower technological index (6.67) in the study area indicates the greater technological feasibility under farmer field conditions. [ABSTRACT FROM AUTHOR]

Pink bollworm (PBW), Pectinophora gossypiella (Saunders) is a notorious monophagous pest of cotton. Any changes in the nutritional quality of cotton have direct influences on the life cycle of the pink bollworm. In this regard, the host-mediated effect of elevated carbon dioxide (CO2) and temperature on the life cycle of pink bollworm, P. gossypiella on Bt cotton was studied in the open top chambers at the Center for Agro-climatic Studies, UAS, Raichur. The results revealed that variations in phyto-chemistry of Bt cotton particularly the Crytoxin expression and nitrogen have reduced in elevated CO2 and temperature conditions and also reduced the larval, pupal period, adult longevity, fecundity and incubation period. However, there was no significant difference in the biology of PBW among the climate change treatments. Similar results were noticed when PBW was reared on Bt cotton collected from different open top chambers and reared separately in growth chambers and the same larvae were analyzed for their enzyme activity. The results showed that there was significant increase in the activity of midgut proteases (trypsin and chymotrypsin) and carbohydrases (a-amylase) and decrease in the activity of lipase enzyme was noticed. [ABSTRACT FROM AUTHOR]