The pink bollworm (Pectinophora gossypiella, PBW) is a major cotton pest, causing economic losses by damaging seeds and fiber. Cotton growers typically use systemic and broad-spectrum insecticides for its management, which pose risks to human health and the environment. Consequently, there is a need for eco-friendly alternatives. This study evaluates the bio-efficacy of the entomopathogenic fungus Metarhizium anisopliae strain TMBMA1 against pink bollworm and assesses its compatibility with major insecticides. Additionally, to comprehend the dynamics of colonization and the infection processes of entomopathogenic fungi (EPF), scanning electron microscopy (SEM) of infected larvae was carried out. We challenged the second instar PBW larvae to eight different concentrations (1 × 103 to 1 × 1010 conidia mL−1) of an M. anisopliae strain TMBMA1. The highest mortality (100

Aim: To identify natural incidence pattern of pink bollworm larval parasitoids across different cotton growing zones in India. Methodology: Green bolls of cotton were collected from farmers field across India encompassing Northern, Central and Southern regions of cotton cultivation. In total 59 locations were selected for sampling and from each cotton field, five hundred matured green bolls were collected, packed and transferred to laboratory at CICR, Nagpur. Dead/inactive larvae were placed individually in plastic tubes under controlled laboratory conditions to monitor parasitoid emergence. Percent parasitization and parasitoid emergence were calculated accordingly. Results: The pink bollworm larval recovery varied among locations, with the highest average recovery and parasitised larvae observed in the Northern zone (480.50 and 12.10 larvae). Additionally, the average parasitization rate was higher in the Northern cotton zone (2.46 %) compared to the Southern (2.16 %) and Central zones (1.70 %). In terms of parasitoids, the Southern zone exhibited the highest average number of Bracon lefroyi (9.17 ± 3.59) with a range of 3.0-17.0 parasitoids, while the Northern zone recorded the highest average number of Apanteles angaleti (9.70 ± 2.83) with a range of 6.0-15.0 parasitoids. Interpretation: The natural parasitization of pink bollworm larvae by Bracon lefroyi and Apanteles angaleti ranged from 0.43 to 4.33 per cent across various cotton-growing zones. This natural occurrence presents a hopeful strategy for controlling pink bollworm populations, potentially reducing the need for chemical interventions and minimizing crop damage. Key words: Apanteles angaleti, Bracon lefroyi, Cotton, Larval parasitoid, Pink bollworm

Cotton is an important cash crop in India, confronts a significant threat from the pink bollworm, Pectinophora gossypiella (Saunders), a pest that has developed resistance to genetically modified cotton and various insecticides. Physiological adaptations, such as enhanced detoxification and altered target site sensitivity, high genetic diversity and growing long season with monoculture Bt cotton contributes P. gossypiella resistance against the various management strategies. The challenges posed by pest resistance impact cotton productivity and environmental sustainability, prompting a shift from conventional insecticide-centric methods to dynamic, adaptive pest management. This review investigates the mechanisms behind P. gossypiella resistance in Indian cotton, exploring genetic, physiological, and behavioral adaptations enabling the pest to withstand conventional control measures. Present analysis provides insights into the complex interaction between P. gossypiella and Indian cotton, offering a roadmap for sustainable pest management.

Context: The development of pink bollworm (PBW) resistance to Bt cotton and the rise of boll rot (BR) disease pose significant challenges to cotton production in India. Both PBW and BR significantly reduce cotton yields by damaging seeds and lint. Damage caused by PBW often resembles BR infection leading to misdiagnosis and incorrect control measures. The lack of precise methods for quantifying yield losses caused by PBW and BR prompted genesis of this study. Objective: This study aimed to develop a reliable and robust method for quantifying yield losses caused by PBW and BR, and to predict future yield loss trends for PBW by integrating a phenology model with field data collected from various cotton-growing regions of India. Methods: Yield loss calculation involved assessing the PBW and BR incidence levels and working proportionate weight loss in randomly sampled loculi from cotton fields. Using a temperature-driven phenology model coupled with a geographic information system, PBW infestation risk was mapped across India's cotton-growing areas and its population growth was simulated under various climate change scenarios predicting temperature rise between 0.5 and 2.5 degrees C over current temperature. Phenology model driven activity index, expressed as population abundance of PBW was regressed over field damage data from 15 different Indian cotton-growing locations to predict future yield loss trends under climate change scenarios. Results and conclusions: Without control measures, PBW and BR individually could cause potential yield losses of similar to 25 %, equating to an annual loss of 4.27 million tons out of 17.09 million tons of seed cotton produced in India. With control measures, PBW caused an actual yield loss of 3.75 %, equating 0.64 million tons of seed cotton, annually. Currently PBW undergoes over six generations annually in about 60 % of India's cotton-growing areas, increasing to 80 % by 2050 with climate change. Future PBW population abundance is expected to decline due to reduced survival and reproduction at higher temperatures, resulting in a slight decline in future yield loss trends. Significance: This study provides a robust and reliable tool for quick yield loss assessment during pest or disease outbreaks and also introduces a new dimension of linking PBW phenology model with actual field damage data to improve management strategies for cotton pink bollworm.

Pink bollworm strains (F0) collected from 59 geographically different locations across India were advanced to F1 and screened for Cry toxin resistance using 21-days diet incorporation bioassay. The survived population from five locations with the highest LC50 values for Cry1Ac were grouped as highly resistant, while those from five locations with lower LC50 values were grouped as relatively less resistant. Similarly, populations with high and relatively low resistance to Cry2Ab were also developed. Further, these populations advanced to next generation. One-day-old neonate larvae from all populations, along with a susceptible strain (F194), were exposed to various selected doses to evaluate the precise impact of these concentrations on biological fitness. The results indicated that higher concentrations of Cry toxin prolonged the larval, pupal, and total developmental durations, while reducing adult longevity, fecundity, and egg hatchability. Egg incubation period, however, remained unaffected. Susceptible strains on toxin-free diet exhibited the shortest development times (larval: 18.48 ± 0.95 d; pupal: 7.22 ± 0.36 d; total: 39.41 ± 2.52 d), longest adult life (9.78 ± 0.35 d), highest fecundity (123.15 ± 4.95 eggs/female), and greatest survival rates (> 95%). Their growth (5.28) and survival indices (0.97) reflected robust development under non-stress conditions. Conversely, toxin exposure increased mortality and malformations, particularly in susceptible strains. Fitness costs due to Cry1Ac exposure were highest in susceptible strains (84.42% at 1.0 µg/ mL), followed by less resistant (79.46%) and highly resistant strains (60.07% at 10.0 µg/ mL). For Cry2Ab, the relatively less resistant strain showed the highest fitness cost (74.51%), followed by susceptible (58.82%) and highly resistant strains. Overall, fitness costs were closely linked to reduced fecundity, egg hatchability, larval survival, adult emergence, and prolonged development.

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a serious pest known for its ability to feed on various crops, particularly maize, inflicting significant reduction in maize yield. Farmers have traditionally dependent on chemical insecticides to manage this pest. These insecticides are frequently ineffective because the pest’s hidden feeding habits hinder the chemicals from reaching their intended target. In response to this challenge, an in vitro bioassay was performed to evaluate the virulence of an entomopathogenic nematode Steinernema siamkayai against third-instar larvae of Spodoptera frugiperda and wax moth (Galleria mellonella) at different concentrations of infective juveniles. Mortality rates were monitored from 24 to 96 h post-inoculation, with S. siamkayai demonstrating notable effectiveness against both insect species. For the fall armyworm, mortality rates risen progressively, beginning at 16.66% for 100 IJs larva-1 after 24 h, reaching 83.33% at 48 h, and achieving 100% by 96 h for doses of 30 IJs larva-1 or more. Wax moth larvae, on the other hand, showed greater susceptibility, with 22.91% mortality at 5 IJs larva-1 within 24 h and 100% mortality at 100 IJs larva-1 by the 48-hour mark. After 96 h, complete mortality was recorded in both species at doses of 30 IJs larva-1 or higher. Probit analysis indicated lower LC50 values for G. mellonella (1.83 and 0.87 IJs larva-1 at 72 and 96 h) compared to FAW (9.83 and 5.47 IJs larva-1). These findings suggest that S. siamkayai is a highly efficient bio-control agent, especially for managing S. frugiperda, and shows potential for integration into pest management programs.

Cotton crop is infested by numerous arthropod pests from sowing to harvesting, causing substantial direct and indirect yield losses. Knowledge of seasonal population trends and the relative occurrence of pests and their natural enemies is required to minimize the pest population and yield losses. In the current study, analysis of the seasonal population trend of pests and natural enemies and their relative occurrence on cultivars of three cotton species in Central India has been carried out. A higher number and diversity of sucking pests were observed during the vegetative cotton growth stage (60 days after sowing), declining as the crop matured. With the exception of cotton jassid (Amrasca biguttula biguttula Ishida), which caused significant crop damage mainly from August to September; populations of other sucking insects seldom reached economic threshold levels (ETL) throughout the studied period. The bollworm complex populations were minimal, except for the pink bollworm (Pectinophora gossypiella Saunders), which re-emerged as a menace to cotton crops during the cotton cropping season 2017–2018 due to resistance development against Bt-cotton. A reasonably good number of predatory arthropods, including coccinellids, lacewings, and spiders, were found actively preying on the arthropod pest complex of the cotton crop during the early vegetative growth stage. Linear regression indicates a significant relationship between green boll infestations and pink bollworm moths in pheromone traps. Multiple linear regression analyse showed mean weekly weather at one- or two-week lag periods had a significant impact on sucking pest population (cotton aphid, cotton jassid, cotton whitefly, and onion thrips) fluctuation. Gossypium hirsutum cultivars RCH 2 and DCH 32, and G. barbadense cultivar Suvin were found susceptible to cotton jassid and onion thrips. Phule Dhanvantary, an G. arboreum cotton cultivar, demonstrated the highest tolerance among all evaluated cultivars against all sucking pests. These findings have important implications for pest management in cotton crops. Susceptible cultivars warrant more attention for plant protection measures, making them more input-intensive. The choice of appropriate cultivars can help minimize input costs, thereby increasing net returns for cotton farmers.

Climate change factors, including elevated carbon dioxide (eCO2), elevated ozone (e03), and the combined effect of elevated temperature and CO2 (eT+eCO2), significantly influence the population dynamics, development, and feeding behavior of the Brown Planthopper (Nilaparvata lugens, BPH) and its impact on rice yield. A two-year field study (2019–2020) showed that BPH populations were highest under eCO2 (61.6 ± 13.5 and 50.6 ± 12.3 N. lugens/hill) and moderate under eT+eCO2 (44.5 ± 9.4 and 47.5 ± 12.1 N. lugens/hill), while e03 drastically reduced populations (17.7 ± 3.1 and 25.1 ± 7.0 N. lugens/hill). Fecundity followed a similar trend, with the highest egg production under eCO2 (219.7 ± 3.3 and 234.3 ± 9.7 eggs/female), moderate under eT+eCO2 (194.2 ± 6.3 and 223.5 ± 9.2 eggs/female), and lowest under e03 (108.4 ± 6.0 and 135.6 ± 3.7 eggs/female). Developmental duration was shortest under eT+eCO2 (14.9 ± 0.3 and 15.9 ± 0.4 days) and longest under e03 (18.2 ± 0.40 and 21.7 ± 0.40 days). Feeding intensity, indicated by honeydew excretion, was highest under eCO2 (124.8 ± 5.3 and 131.3 ± 4.2 mm²), reduced under eT+eCO2 (105.7 ± 4.9 and 107.6 ± 3.4 mm²), and lowest under e03 (44.2 ± 2.5 and 48.9 ± 2.6 mm²). Results indicated that eCO2 promoted overall plant growth, with the highest plant height (65.4 ± 0.8 cm) and reproductive tillers (22.2 ± 0.6). However, under BPH infestation, eCO2 also resulted in the highest yield reduction (15.9%) despite producing the highest grain yield under uninfested conditions (40.1 ± 0.3 g/hill). The eT+eCO2 treatment exhibited moderate reductions in plant height (62.4 ± 0.6 cm) and grain yield (38.1 ± 0.4 g/hill), with a yield loss of 11.5% under infestation. The e03 treatment negatively impacted plant growth, significantly reducing plant height (54.8 ± 1.0 cm), total tillers (17.7 ± 0.9), and grain yield (27.5 ± 0.2 g/hill) in uninfested conditions, with a lower yield reduction (8.72%) under infestation. The findings of this study indicate that pests and host plants benefited under eCO2 and eT+eCO2 conditions; however, increasing BPH populations caused yield losses. Nevertheless, e03 had a detrimental effect on pests as well as host plants. The results pertaining to the collective impact of climate change factors on both the host plant and pests have the potential to contribute to the advancement of insect pest management strategies in response to shifting climates.

Oviposition deterrents are the semiochemicals that provide the first line of defense by modifying the behavior of conspecific females. In the present study, the oviposition deterrent effect of four fatty acids (linoleic, palmitic, myristic and stearic acid) and six vegetable oils (groundnut, rice bran, safflower, sesame, soybean and sunflower) having fatty acids was confirmed in bioassays under laboratory conditions at different concentrations against the old-world bollworm Helicoverpa armigera. The value of the avoidance index (Ai) and percent effective deterrence (PED) confirmed the role of fatty acids and vegetable oils as an oviposition deterrent. It was found that there was a negative correlation between the ratio of the number of eggs laid and the concentrations of fatty acids tested against H. armigera. The efficacy of fatty acids and vegetable oils as oviposition deterrents concerning Ai and PED was observed. The highest Ai and PED values were observed in palmitic acid (Ai = 0.57, PED = 73

The study investigated the comparative biology of pink bollworm (PBW) reared on artificial diet and okra under controlled laboratory conditions with the temperature (27 ± 2 °C), relative humidity (65 ± 5%), and a 14:10 hours light-dark photoperiod during 2021-22 at ICAR-Central Institute for Cotton Research (CICR), Nagpur.The results indicated no significant difference in egg incubation, larval, prepupal, pupal, and oviposition periods between PBW reared on artificial diet and okra.However, adult longevity, total life cycle duration, and oviposition-related parameters exhibited significant differences.The study also highlighted differences in prepupal and pupal periods, with significant variations in adult longevity.Furthermore, the research demonstrated variations in fecundity and the highest number eggs laid when reared on artificial diet (126.19 ± 13.47) as compared to okra (91.95 ± 6.57).A higher percentage of egg hatching (88.70%) was observed in eggs laid by adults that were fed on an artificial diet, in contrast to pink bollworms fed on okra (84.90 %).Similarly, the percentage of adult emergence and survival rate was greatest (89.64% and 87.48%, respectively) in pink bollworms nourished with an artificial diet compared to those fed on okra (81.34% and 74.16 %, respectively).The total life cycle duration was found to be longer on artificial diet (40.92±4.89)compared to okra (38.60±3.60),emphasizing the influence of diet on PBW development.Overall, this investigation provides valuable insights into the biology and development of pink bollworm in relation to different food sources.

Cocoa is a commercially important beverage crop that faces new challenges in the context of climate change, which can alter pest and disease dynamics in cocoa plantations. In the Dakshina Kannada district of Karnataka, India, an abrupt increase in cocoa wilt was observed during the 2017-18 and 2018-19 periods. Systematic examination of affected trees revealed consistent attacks of Euwallacea fornicatus (Eichhoff, 1868; Coleoptera: Curculionidae: Scolytinae. In-depth studies of the wilted trees revealed the association of the plant pathogenic fungus Fusarium sp. with Euwallacea fornicatus. The identity of the obtained pure culture from the insect and infected tree was confirmed as Fusarium sp. using amplification of ribosomal DNA, RNA polymerase II largest subunit (RPB1) and translation elongation factor 1 (Tef1) genes. Notably, this study reports a remarkable case of mutualistic association between ambrosia beetles and Fusarium sp., belonging to the Fusarium solani species complex (FSSC), rather than the Ambrosia Fusarium clade (AFC). This finding highlights the intriguing diversity of mutualistic relationships in nature and sheds new light on the complex interactions between organisms. The present study also investigated the impact of rainfall on the colonization and spread of the Euwallacea-Fusarium complex. The findings revealed that rainfall was identified as a predisposing factor for the incidence and spread of attacks. Additionally, the study conducted a comprehensive analysis of the modeling of Euwallacea-Fusarium complex spread over a specific period of time.

Aim: This preliminary study aimed to investigate the movement patterns of Pectinophora gossypiela (Saunders) (Lepidoptera: Gelechiidae) larvae in the rosette flowers. Methodology: Field experiments conducted on the migration behavior of pink bollworm larvae with respect to rosette flowers in cotton fields. Observations included monitoring infested flowers, larval stage duration within rosette flowers, and larval movement to soil for pupation, larval mortality post-drop, and larval migration to early bolls, all conducted without insecticide application to reflect natural conditions. Results: The movement of the larvae was tracked and recorded from the start of flowering to the boll formation stage. Nearly, 44.88% of the larvae present on the infested flowers had moved to the soil for pupation, while 14.29% had moved to newly formed bolls on the same rosette flower. Additionally, 30.90% of the larvae had moved to dry leaf debris on the soil, and the remaining 9.93% either escaped or died due to environmental factors such as damp soil. Notably, the study showed that dry soils or light debris accumulation were the most favorable environments for pink bollworm larvae. Interpretation: The present study has generated useful information regarding the movement of PBWs larvae from rosette flowers to bolls that contribute to infestation. Hence, by implementing integrated pest management strategies during the early crop periods between 60 and 100 DAS, green boll infestations can be avoided and economic yields improved.

India is the world’s largest cotton producer and the only country that grows all four cultivated cotton species. There have been very few studies on the diversity and abundance of natural enemies of cotton insect pests in these cultivated cotton species. Therefore, the current study (2016–2018) was conducted to assess the diversity and abundance of natural enemies that cultivated cotton species harbour. Phule Dhanwantari, Suraj, Suvin, RCH-2, and DCH-32 were the five genotypes used in the study, each with a distinct genetic background. Using the adiv 2.0.1 and vegan R packages, we identified significant differences in natural enemies in terms of species diversity, richness, evenness, and abundance. Analysis of Similarity (ANOSIM) and Non-metric Multidimensional Scaling (NMDS) indicated substantial differences in the natural enemy community structure among the examined genotypes. A total of 17,279 natural enemies were collected and identified across genotypes from seven predatory families and five parasitoid families. The percentage share of these natural enemy families across genotypes and years, in descending order, is Coccinellidae (28.23%) < Tachinidae (19.23%) < Braconidae (12.68%) < Chrysopidae (11.65%) < Chalcididae (9.41%) < Aphelinidae (6.33%) < Pentatomidae (3.29%) < Ichneumonidae (2.37%) < Syrphidae (2.33%) < Vespidae (1.81%) < Asilidae (1.79%) < Geocoridae (0.89%). Coccinellidae, Tachinidae, Braconidae, Chrysopidae, Chalcididae, and Aphelinidae are the six major families that account for more than 85% of all recorded natural enemies. These six families have a higher percentage share in Phule Dhanwantary (90%) compared to the other genotypes. The conservation and better utilization of these natural enemies are crucial for the ecological and safe management of insect pests in the cotton ecosystem.

The biological traits and thermal needs of Trichogrammatoidea bactrae Nagaraja was assessed on the eggs of the Pink bollworm, Pectinophora gossypiella to predict the ideal temperature for the release of the parasitoid. A card with 300 P. gossypiella eggs was offered to T. bactrae adults in a 5:1 ratio at temperatures 18, 20, 22, 24, 26, 28, 30, 32, 34 and 36 oC. All developmental stages of T. bactrae were monitored at each temperature, however, no parasitism or development occurred at temperature 36°C. The highest parasitism rate was observed at 28°C (76.03%), and emergence rates exceeded 85.65% between 18 and 30°C. Temperature variations affected both the development duration and adult longevity, with higher temperatures leading to shorter development times and reduced lifespan. The highest proportion of female offspring was recorded at 20°C (73.67%). The total heat requirement for complete development was calculated to be 136.98 degree-days (K), with a lower threshold temperature identified at 11.75°C.

Cotton (Gossypium sp.) is the one of the major commercial fibre crops cultivated across the country. The yield is severely affected by insect pests and diseases. Pink bollworm, Pectinophora gossypiella (Saunders, 1844) is one of the major insect pests threatening the cultivation of cotton. The major constraint limiting cotton production is resistance, which prevails to date due to the indiscriminate use of the insecticides and noncompliance of the refugia. Hence the status of the pest needs to be ascertained periodically to initiate timely and dynamic management tactics. For conducting laboratory screening, a higher number of individuals is the prime requirement, which is facilitated through massrearing techniques. We have evaluated different oviposition substrates like paper and muslin cloth for enhancing the recovery of eggs. Our results are quite promising and the use of black muslin cloth has shown a recovery of eggs on par with natural substrate (cotton twig). Adoption of the artificial substrate has huge potential in rearing techniques and avoids drawbacks like tissue drying, carry-over of diseases and reusability.

Pink bollworm (PBW) Pectinophora gossypiella is an important pest cotton worldwide. There are multiple factors which determines the occurrence and distribution of P. gossypiella across different cotton growing regions of the world, and one such key factor is ‘temperature’. The aim was to analyze the life history traits of PBW across varying temperature conditions. We systematically explored the biological and demographic parameters of P. gossypiella at five distinct temperatures; 20, 25, 30, 35 and 40 ± 1 °C maintaining a photoperiod of LD 16:8 h. The results revealed that the total developmental period of PBW shortens with rising temperatures, and the highest larval survival rates were observed between 30 °C and 35 °C, reaching 86.66% and 80.67%, respectively. Moreover, significant impacts were observed as the pupal weight, percent mating success, and fecundity exhibited higher values at 30 °C and 35 °C. Conversely, percent egg hatching, larval survival, and adult emergence were notably lower at 20 °C and 40 °C, respectively. Adult longevity decreased with rising temperatures, with females outliving males across all treatments. Notably, thermal stress had a persistent effect on the F1 generation, significantly affecting immature stages (egg and larvae), while its impact on reproductive potential was minimal. These findings offer valuable insights for predicting the population dynamics of P. gossypiella at the field level and developing climate-resilient management strategies in cotton.

Silicon (Si) is known to enhance plant resistance in rice and other Poaceae plants by priming chemical defence, physiological, and mechanical barriers. However, the effects of application of Si to the soil on plant defence through antioxidative enzymes and changes in the nutrient composition of soil and rice straw under climate change conditions remain unclear. Thus this study was aimed at investigating the effects of Si on plant defence and other biochemical changes in the brown planthopper (BPH), Nilaparvata lugens (St & aring;l, 1854), soil and rice plants under elevated CO 2 levels (570 +/- 25 ppm) and elevated temperature ( <^> 3 degrees C higher than ambient) in open-top chambers (OTCs) during the rainy season of 2019 and 2020. The results revealed that under elevated CO 2 , Si amendment significantly enhanced the activity of defensive antioxidative enzymes, namely catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) upon BPH feeding in both plants and BPH, besides enhancing available forms of major nutrients, namely nitrogen (N), phosphorus (P), potassium (K), and minor nutrients, namely calcium (Ca), magnesium (Mg) and sulphur (S), and Si in soil and rice plants. The antioxidative enzymes' mediated plant defence and positive alteration of the nutrient composition of soil along with other reported plant defences, namely callose deposition, silicification, and positive alteration of photosynthesis-related parameters, indicated Si amendment as a potential alternative strategy for BPH management under climate change conditions.

The rice leaf folder Cnaphalocrocis medinalis Guenee has become a major concern, causing outbreaks in various parts of India. A lifetable study was conducted to analyze the growth, survival, reproduction, and mortality of C. medinalis, aiming to determine the weakest lifestages and unravel its population dynamics. The study observed the highest survival rate at the fourth-instar larval stage and the lowest during the egg and first-instar larval stages. A population trend index of 5.9 was observed, indicating significant population growth.