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Summary: Decades of studies have shown that Bt corn, by reducing insect damage, has lower levels of mycotoxins (fungal toxins), such as aflatoxin and fumonisin, than conventional corn. We used crop insurance data to infer that this benefit from Bt crops extends to reducing aflatoxin risk in peanuts: a non‐Bt crop. In consequence, we suggest that any benefit–cost assessment of how transgenic Bt crops affect food safety should not be limited to assessing those crops alone; because the insect pest control offered by Bt crops affects the food safety profile of other crops grown nearby. Specifically, we found that higher Bt corn and Bt cotton planting rates in peanut‐growing areas of the United States were associated with lower aflatoxin risk in peanuts as measured by aflatoxin‐related insurance claims filed by peanut growers. Drought‐related insurance claims were also lower: possibly due to Bt crops' suppression of insects that would otherwise feed on roots, rendering peanut plants more vulnerable to drought. These findings have implications for countries worldwide where policies allow Bt cotton but not Bt food crops to be grown: simply planting a Bt crop may reduce aflatoxin and drought stress in nearby food crops, resulting in a safer food supply through an inter‐crop "halo effect." [ABSTRACT FROM AUTHOR]

The cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a significant cotton pest worldwide. Bacillus thuringiensis (Bt) cotton producing Cry1Ac has been used since 1997 for the control of this pest in China and a significant increase in H. armigera resistance to Cry1Ac has occurred in northern China. To mitigate resistance evolution, it is necessary to develop and plant pyramided 2- and 3-toxin Bt cotton to replace Cry1Ac cotton. For sustainable use of pyramided Bt cotton, we used diet overlay bioassays to measure the baseline susceptibility of H. armigera to Cry2Ab in 33 populations collected in 2017, 2018, and 2021 in 12 locations from major cotton-producing areas of China. The lethal concentration killing 50% (LC50) or 99% (LC99) of individuals from the populations ranged from 0.030 to 0.138 µg/cm2 and 0.365 to 2.964 µg/cm2, respectively. The ratio of the LC50 for the most resistant and susceptible population was 4.6, indicating moderate among-population variability in resistance. The susceptibility of H. armigera to Cry2Ab did not vary significantly over years. A diagnostic concentration of 2 µg/cm2 was calculated as twice the LC99 from an analysis of pooled data for the field-collected populations. This concentration discriminated well between susceptible and resistant individuals, as it killed all larvae from a susceptible laboratory strain and 0%, 0%, and 23% of larvae from 3 laboratory strains with > 100-fold resistance to Cry2Ab. These baseline susceptibility data and diagnostic concentration for Cry2Ab will be useful for monitoring the evolution of H. armigera resistance to pyramided Bt cotton in China. [ABSTRACT FROM AUTHOR]

ABSTRACT Scholars of critical agrarian political economy see agriculture in liberalization‐era India as a form of disguised unemployment, part of wider agrarian distress. This article engages with literature differentiating the class/caste responses to agrarian and non‐farm livelihood distress in India to understand the different diversification options that households have available. The article draws on research carried out in a village in dryland, Bt cotton‐dependent Telangana in south India to show these variegated practices. While Other Backward Caste households invested in livestock to cope with heavy Bt cotton investments and losses, Scheduled Caste households focused on the educated rural youth, relying on their non‐farm wage labour in jobs such as taxi driving. Despite rural–urban migration and higher levels of education, under/unemployment remains persistent for rural youth. In this context, Ryuthu Bandhu, a cash transfer programme pioneered in Telangana in 2018, proved crucial for rural livelihood survival in the study village, contributing up to 22 per cent of annual household incomes. However, negative average net incomes across all households show that attempts to diversify out of distress have been largely unsuccessful. [ABSTRACT FROM AUTHOR]

Background: Bt technology has played significant role in controlling bollworms and increasing cotton yield in earlier days of its introduction, a subsequent decline in yield became apparent over time. This decline may be attributed to various environmental factors, pest dynamics, or combination of both. Therefore, the present biophysical survey and questionnaire were designed to evaluate the impact of Bt cotton on bollworms management and its effect on reducing spray costs, targeting farmers with varied landholdings and educational backgrounds. Additionally, data on farmers' cultivated varieties and the prevalence of bollworms and sucking insects in their fields were recorded. Subsequently, about eleven thousand cotton samples from farmer fields were tested for Cry1Ac, Cry2Ab and Vip3A genes by strip test. Results: In this analysis, 83% of the farmers planting approved varieties believe that Bt technology control bollworms, while 17% hold contradictory views. Similarly, among farmers cultivating unapproved varieties, 77% agree on effectiveness of Bt technology against bollworms, while 23% disagree. On the other hand, 67% of farmers planting approved varieties believe that Bt technology does not reduce spray costs, while 33% agree with the effectiveness. Similarly, 78% of farmers cultivating unapproved varieties express doubt regarding its role to reduce spray costs, while 22% are in favour of this notion. Differences in opinions on the effectiveness of Bt cotton in controlling bollworms and reducing spray cost between farmers planting unapproved and approved varieties may stem from several factors. One major cause is the heavy infestation of sucking insects, which is probably due to the narrow genetic variation of the cultivated varieties. Additionally, the widespread cultivation of unapproved varieties (21.67%) is also an important factor to cause different opinions on the effectiveness of Bt cotton. Conclusion: Based on our findings, we propose that the ineffective control of pests on cotton crop may be attributed to large scale cultivation of unapproved varieties and non-inclusion of double and triple transgene technologies in country's sowing plan. On the basis of our findings, we suggest cotton breeders, regulatory bodies and legislative bodies to discourage the cultivation of unapproved varieties and impure seed. Moreover, the adoption of double and triple Bt genes in cottons with a broad genetic variation could facilitate the revival of the cotton industry, and presenting a promising way forward. [ABSTRACT FROM AUTHOR]

Cotton plays a crucial role in shaping Indian economy and rural livelihoods. The cotton crop is prone to numerous insect pests, necessitating insecticidal application, which increases production costs. The advent of the expression of Bacillus thuringiensis (Bt) insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health. After the introduction of transgenic cotton, the cultivated area expanded to 22 million hectares, with a 64% increase in adoption by farmers worldwide. Currently, Bt cotton accounts for 93% of the cultivated cotton area in India. However, extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm. Furthermore, the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides, favouring the emergence of secondary pests with significant challenges. This emphasizes the urgent necessity for developing novel pest management strategies. The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton, but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops. Although gene pyramiding was introduced as a solution, combining mono toxin also led to instances of cross-resistance. Therefore, there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton. Advanced biotechnological strategies, such as sterile insect release, RNA interference (RNAi)-mediated gene silencing, stacking Bt with RNAi, and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR-Cas), offer promising tools for identifying and managing resistance genes in insects. Additionally, CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation. These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis Berliner (Bt) cotton was widely grown in China from 1997. Since then, it has resulted in many misunderstandings and concerns about Bt cotton. However, extensive research and practical experience over the past 28 years in China have led to the resolution of many of these concerns. This short review explores how the concerns has been resolved, and provides valuable insights for the future utilization of genetically modified products. [ABSTRACT FROM AUTHOR]

India ranks second in the global cotton balance, next only China. Cotton is the mainstay of India's textile industry, accounting for roughly 74% of total textile mill usage. India's cotton production has increased due to the introduction and rapid geographical expansion of bollworm resistant Bt cotton. The objective of this paper is to compare cotton balance analyses and to investigate the factors that have influenced cotton development over the last 22 years. The pertinent arguments presented in this article support the analytical discussion of the cotton trade's yearly trends. Between 2000-01 and 2021-22, there will be an average of 30 million bales of cotton produced, 5.6 million exported and 1.4 million imported by India. By adding observable carryover stocks, the entire supply of cotton in India has consistently outperformed the total demand. However, Indian cotton farmers face a variety of issues, including increasing production costs, unmanageable debts, stagnant yields, constant pesticide use, inadequate irrigation, a lack of modern technology, manual picking, vulnerability to contamination, deterioration in genetic purity, competition from artificial fibres, particularly synthetic fibre, fluctuating market prices and lack of CCI participation. To boost cotton output, governments must provide high-yielding, high-quality hybrid seeds and appropriate irrigation infrastructure. [ABSTRACT FROM AUTHOR]

During the boll formation stage, cotton bolls exhibit the lowest expression of Bacillus thuringiensis (Bt) insecticidal proteins. Resistance to insects varies notably among different organs, which poses challenges for controlling cotton bollworms. Consequently, an experimental strategy was designed in the 2020–2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation. Two Bt cultivars of Gossypium hirsutum, namely the hybrid Sikang 3 and the conventional Sikang 1, were used as test materials. Three treatments were applied at the peak flowering period: CK (the control), T1 (amino acids), and T2 (amino acids and EDTA). The results show that, in comparison to the CK group, the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments. The maximum levels of increase observed were 67.5% in cotton bolls and 21.7% in leaves. Moreover, the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%. Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism, which are independent of Bt gene expression levels. Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity, while reducing the catabolic enzyme activities, are instrumental in enhancing the Bt protein content. Consequently, the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.

Abstract Cotton plays a crucial role in shaping Indian economy and rural livelihoods. The cotton crop is prone to numerous insect pests, necessitating insecticidal application, which increases production costs. The advent of the expression of Bacillus thuringiensis (Bt) insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health. After the introduction of transgenic cotton, the cultivated area expanded to 22 million hectares, with a 64% increase in adoption by farmers worldwide. Currently, Bt cotton accounts for 93% of the cultivated cotton area in India. However, extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm. Furthermore, the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides, favouring the emergence of secondary pests with significant challenges. This emphasizes the urgent necessity for developing novel pest management strategies. The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton, but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops. Although gene pyramiding was introduced as a solution, combining mono toxin also led to instances of cross-resistance. Therefore, there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton. Advanced biotechnological strategies, such as sterile insect release, RNA interference (RNAi)-mediated gene silencing, stacking Bt with RNAi, and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR-Cas), offer promising tools for identifying and managing resistance genes in insects. Additionally, CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation. These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton.

Abstract Bacillus thuringiensis Berliner (Bt) cotton was widely grown in China from 1997. Since then, it has resulted in many misunderstandings and concerns about Bt cotton. However, extensive research and practical experience over the past 28 years in China have led to the resolution of many of these concerns. This short review explores how the concerns has been resolved, and provides valuable insights for the future utilization of genetically modified products.

Background: Sudden temperature drops, resulting from extreme weather events, often occur during the boll-setting period of cotton in Xinjiang, China, causing decreased expression of Bacillus thuringiensis (Bt) insecticidal proteins in cotton bolls. The precise threshold temperatures and durations that lead to significant changes in Cry1Ac endotoxin levels under low temperatures remain unclear. To address this, we investigated the effects of different temperatures and stress durations on Cry1Ac endotoxin levels in cotton bolls. In 2020–2021, two Bt transgenic cotton varieties, conventional Sikang1 and hybrid Sikang3, were selected as experimental materials. Various low temperatures (ranging from 16 to 20 °C) with different durations (12 h, 24 h and 48 h) were applied during the peak boll-setting period. Results: As the temperature decreased, the Cry1Ac endotoxin content in the boll shell, fiber, and seed exhibited a declining trend. Moreover, the threshold temperature which caused a significant reduction in Cry1Ac endotoxin content increased with the prolonged duration of low-temperature stress. Among the components of cotton bolls, seeds were most affected by low-temperature stress, with the threshold temperature for a significant reduction in Cry1Ac endotoxin content ranging from 17 °C to 19 °C. Correlation analysis indicated that low temperatures led to a decrease in protein synthesis capacity and an increase in degradation ability, resulting in reduced Cry1Ac endotoxin content. Pathway analysis revealed that both free amino acid and peptidase had significant negative effects on Cry1Ac endotoxin content. Conclusion: In summary, when the daily average temperature was ≤ 19 °C, implementing cultural practices to reduce free amino acid content and peptidase activity could serve as effective cold defense strategies for Bt cotton production. [ABSTRACT FROM AUTHOR]

The effectiveness of a hybrid unmanned aerial vehicle (UAV) for optimizing crop booster application on cotton crops (variety Co-14) at Tamil Nadu Agricultural University is evaluated in this research. The hybrid UAV, featuring a 12-litre sprayer tank and powered by an internal combustion engine and brushless direct current motor, was tested at heights of 1 and 2 m and speeds of 3 and 4 m s –1. The objective was to determine optimal parameters for maximizing droplet deposition and minimizing spray drift. The results indicated that at 1 m and 3 m s –1, the droplet density in the target area was 148 ± 8 drops/cm², compared to 136 ± 4 drops/cm² at 2 m. The volume median diameter at 1 m and 3 m s –1 was 361 µm, and the number median diameter was 392 µm, showing higher deposition and uniform droplet sizes at lower heights and lower speeds. Spray drift analysis indicated reduced off-target movement at 1 m and 3 m s –1, showing a non-target droplet density of 54 ± 4 drops/cm² compared to 42 ± 6 drops/cm² at 2 m. The study concludes that the optimal UAV operation parameters are 1 m height and 3 m s –1 speed, enhancing droplet deposition, minimizing drift, and improving spray efficiency. [ABSTRACT FROM AUTHOR]

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]

BACKGROUND: Transgenic crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) have been used to manage insect pests for nearly 30 years. Dose of a Bt crop is key to assessing the risk of resistance evolution because it affects the heritability of resistance traits. Western corn rootworm (Diabrotica virgifera virgifera, LeConte), a major pest of maize, has evolved resistance to all commercially available Bt traits targeting it, and threatens resistance to future transgenic traits. Past research shows the dose of Bt maize targeting western corn rootworm can be confounded by larval density‐dependent mortality. We conducted a 2‐year field study at two locations to quantify larval density‐dependent mortality in Bt and non‐Bt maize. We used these results to calculate dose for our method and compared it to three previously published methods. Additionally, adult emergence and root injury were analyzed for predicting initial egg density. RESULTS: Increased pest density caused greater proportions of larvae to die in Bt maize than in non‐Bt maize. All methods for calculating dose produced values less than high‐dose, and stochastic variation had the greatest impact on dose at high and low pest densities. Our method for calculating dose did not produce values positively correlated with pest density while the three other methods did. CONCLUSION: To achieve the most accurate calculation of dose for transgenic maize targeting western corn rootworm, density‐dependent mortality should be taken into account for both transgenic and non‐transgenic maize and assessed at moderate pest densities. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

SUMMARY: Cotton is a globally cultivated crop, producing 87% of the natural fiber used in the global textile industry. The pigment glands, unique to cotton and its relatives, serve as a defense structure against pests and pathogens. However, the molecular mechanism underlying gland formation and the specific role of pigment glands in cotton's pest defense are still not well understood. In this study, we cloned a gland‐related transcription factor GhHAM and generated the GhHAM knockout mutant using CRISPR/Cas9. Phenotypic observations, transcriptome analysis, and promoter‐binding experiments revealed that GhHAM binds to the promoter of GoPGF, regulating pigment gland formation in cotton's multiple organs via the GoPGF‐GhJUB1 module. The knockout of GhHAM significantly reduced gossypol production and increased cotton's susceptibility to pests in the field. Feeding assays demonstrated that more than 80% of the cotton bollworm larvae preferred ghham over the wild type. Furthermore, the ghham mutants displayed shorter cell length and decreased gibberellins (GA) production in the stem. Exogenous application of GA3 restored stem cell elongation but not gland formation, thereby indicating that GhHAM controls gland morphogenesis independently of GA. Our study sheds light on the functional differentiation of HAM proteins among plant species, highlights the significant role of pigment glands in influencing pest feeding preference, and provides a theoretical basis for breeding pest‐resistant cotton varieties to address the challenges posed by frequent outbreaks of pests. Significance Statement: Pigment glands are essential for cotton's pest defense, but their formation mechanisms remained unclear. We demonstrated that the GhHAM transcription factor, through the GoPGF‐GhJUB1 pathway, is pivotal for gland development and pest resistance, offering new insights into breeding pest‐resistant cotton. [ABSTRACT FROM AUTHOR]

In India, after its introduction in 2002, Bt cotton showed a steep increment in terms of area coverage and presently occupies more than 95% of the total cotton cultivated area; recommended with the planting of structured refuge of the same non-Bt cotton hybrid iso-line at the periphery of the Bt cotton field. Structured refuge compliance is lacking due to farmers' lack of understanding of its significance, along with other challenges like non-isogenic 'refugia' seeds and asynchronous agronomy between main and refuge crops. Though the refugia in Bag concept was studied in 2012, the government introduced 'Refugia in Bag', which mandates 5-10% non-Bt seeds blended with 90-95% Bt seeds in every BG-II hybrid seed packet being sold in the market from June 2020. However, complaints about improper seed proportions led to qualitative ELISA testing, revealing that a substantial number of evaluated hybrids did not adhere to recommended 'refugia' proportions in 2022 and 2023, which may be due to improper dispensing and blending methods during seed packaging. The study emphasizes the need for standardizing blending procedures to ensure adherence to 'Refugia in Bag' standards for all stakeholders. [ABSTRACT FROM AUTHOR]

Over the years, thrips have transitioned from a minor nuisance to a major problem, significantly impacting the yield and quality of cotton. Unmanned aerial vehicles (UAVs) for plant protection have emerged as an effective alternative to traditional pesticide spraying equipment. UAVs offer advantages such as avoiding crop damage and enhancing pesticide deposition on the plants and have become the primary choice for pesticide application in cotton fields. In this study, a 2-year field experiment found that the thrips population in a cotton field in Xinjiang, China, exhibited gradual growth during the early flowering phase, peaking in late July. The thrips population gradually shifted from the lower canopy to the upper canopy as the cotton flowers opened layer by layer. From 09:00 to 11:00 (GMT+8) and 19:00 to 21:00 (GMT+8), thrips mainly flew outside the flowers, while from 17:00 to 19:00 (GMT+8), they mostly inhabited the inner whorls of flowers. The insecticides 10% cyantraniliprole oil dispersion and 10% spinetoram suspension concentrate, sprayed by UAV, had the best control effect on thrips, with 80.51% and 79.22% control effect after 7 days of spraying, respectively. The optimal spraying time for 10% cyantraniliprole oil dispersion was 19:00 (GMT+8), and the control effect on thrips reached 91.16% at 7 days of spraying. During the cotton flowering period, thrips inhabited flowers in the evening and flew outside during the day. The best control effect on thrips was achieved with UAV-sprayed 10% cyantraniliprole oil dispersion at 19:00 (GMT+8). [ABSTRACT FROM AUTHOR]

In cotton ecosystem, number of insect pests simultaneously occur and cause enormous damage to crop. Hence, investigation on succession of sucking pests in Bt cotton cultivar was carried out during 2022 and 2023 at S. D. Agricultural University, Sardarkrushinagar, Gujarat, India. The order of sequential occurrence of pests in Bt cotton was jassid > thrips > whitefly > aphid. Maximum incidence of aphid was observed during 46th standard meteorological week (SMW) (32.30 aphids/3 leaves), while maximum jassids (18.90 jassids/3 leaves) were observed during 42nd SMW. The incidence of whitefly reached to peak level (4.56 whiteflies/3 leaves) during 43rd SMW, however the peak activity of thrips was noticed during 41st SMW (19.72 thrips/3 leaves). The relationship obtained clearly showed that aphid and jassid population exhibited negative and significant correlation with morning and evening relative humidity. The whitefly exhibited negative and significant correlation with morning relative humidity. Highly significant and positive influence on whitefly, thrips and jassid population was noticed with maximum temperature during the study period. [ABSTRACT FROM AUTHOR]

Yield of cotton (Gossypium hirsutum) does not always fall with high temperature (HT) even though this induces significant reductions in fruit retention. To investigate the underlying mechanisms, a greenhouse experiment was conducted with two temperature regimes [control treatment, 28 °C; high temperature (HT), 34 °C] for 7 d. Results showed HT did not significantly influence cotton yield, but reduced boll number and increased boll weight. The 13C distribution ratio of the leaf subtending the cotton boll (LSCB) decreased while that of the cotton boll increased under HT. Transcriptomic and proteomic analyses of the LSCB revealed up-regulated genes involved in cytokinin and jasmonic acid synthesis, as well as SWEET15 (GH_D01G0218), which positively regulated photosynthesis and transport photosynthate, ultimately leading to increased boll weight. After 7 d recovery from HT, the 13C distribution ratio of the LSCB increased while that of the cotton boll decreased. However, boll weight still increased, which was related to increased amylase and sucrose phosphate synthase activities and up-regulated sucrose transport genes in the main-stem leaf and capsule wall. Thus, both accelerated sucrose synthesis and transport in the LSCB under HT and increased sucrose supply ability of the main-stem leaf and capsule wall after recovery from HT contributed to an increased boll weight, which finally maintained cotton yield. [ABSTRACT FROM AUTHOR]

UASD Bt cotton Event-78 based early segregating generations (FF2 & F3) derived from three diverse crosses were evaluated for field incidence of cotton leaf hopper during kharif-F20F21 & F20F2F2 at Agricultural Research Station, UAS, Dharwad. A total 600 FF2 plants from the crosses viz., UASD Bt-78 x DHS-F29, UASDBt-78 x Suvin and Suvin x UASD Bt-78 were screened of which 103,100 and 10F2 plants respective to the three crosses were found to be resistant. The segregation of FF2 population for the jassid tolerance deciphered the implicit "Inhibitory epistasis" mechanism of host plant resistance. Further evaluation of F3 families of these crosses leads to identification of 103 resistant lines from all the three crosses, the mean leafhopper population ranges from 0.67-F2.67 leafhoppers / 3 leaves with the LHRI score of 1. [ABSTRACT FROM AUTHOR]

The inherent insect protection provided by transgenic cotton [Gossypium hirsutum L. (Malvaceae)] has played an appreciable role in profitable cotton production in the U.S. Understanding the effects of variable crystalline protein expression in fruiting structures of dual-gene transgenic cotton on bollworm (Helicoverpa zea Boddie (Noctuidae) larval survival is important to managing the development of insect resistance. Enzyme-linked immunosorbent assays were used to evaluate the relative expression of two crystalline proteins (Cry1Ac and Cry2Ab) present in squares, blooms, and bolls of a Bollgard II cotton variety over time. The effects of these proteins were assessed using third instar larvae from a susceptible colony of bollworms in laboratory bioassays on the respective plant tissues. Both crystalline proteins were positively correlated with bollworm larval mortality and negatively correlated with larval penetration of the epicarp across all fruiting structures of Bollgard II cotton. Bollworm larval mortality was higher in squares (49%) of Bollgard II cotton than in bolls (20%) or blooms (13%). Bollworm larval penetration of fruiting structures was lower in Bollgard II (42%) than non-Bt cotton (75%). In Bollgard II cotton, larval penetration was highest in squares (78%), followed by bolls (63%), and then flowers (36%). Our findings indicate that optical density was effective for assessing the effects of protein expression on bollworm larval mortality in various cotton fruiting structures of a Bollgard II cotton variety. Techniques from this study can be used to understand the contribution of an additional protein, Vip3A that has recently been approved but not tested here, to bollworm larval mortality in newer, third-generation transgenic cottons recently released in the U.S. Resumen La protección inherente de insectos proporcionada por el algodonero transgénico [Gossypium hirsutum L. (Malvaceae)] ha jugado un papel apreciable en la rentabilidad de la producción de algodón en los Estados Unidos. Entendiendo el efecto de las variables de la expresión de proteína cristalina en estructuras fructíferas de los genes duales del algodonero sobre la sobrevivencia de larvas de bellotero [Helicoverpa zea Boddie (Noctuidae)] es importante para manejar el desarrollo de resistencia. Se utilizaron bioensayos con enzimas-ligadas inmunosorbentes para evaluar la expresión relativa de dos proteínas cristalinas (Cry1Ac and Cry2Ab) a través del tiempo en cuadros, flores y frutos del algodonero de la variedad Bollgard II. Se evaluó el efecto de esas proteínas utilizando larvas de tercer instar de una colonia susceptible de bellotero bajo condiciones de laboratorio sobre los respectivos tejidos de plantas. Ambas proteínas cristalinas estuvieron positivamente correlacionadas con la mortalidad de las larvas y negativamente correlacionadas con su penetración de las larvas en las bellotas de la variedad de algodón Bollgard II. La mortalidad de las larvas fue más alta en cuadros (48.89% ± 4.16) de la variedad Bollgard II que en los frutos (20.00% ± 2.66) o flores (13.33% ± 1.93). La penetración de larvas de bellotero sobre las estructuras fructíferas fue más baja en la variedad Bollgard II (42.47% ± 4.59) que en el algodonero no-Bt (75.1% ± 4.76). La penetración de las larvas en la variedad Bollgard II fue más alta en cuadros (77.78% ± 5.76), seguida de los frutos (62.6% ± 4.83) y finalmente de las flores (35.93% ± 6.15). Nuestros resultados indican que la densidad óptica fue efectiva para evaluar el efecto de la expresión de las proteínas sobre la mortalidad de las larvas de bellotero en varias estructuras fructíferas de la variedad de algodón Bollgard II. Las técnicas desarrolladas en este estudio pueden ser utilizadas para tener un mejor entendimiento de la contribución de la proteína Vip3A sobre la mortalidad de larvas con la más nueva, tercera-generación de algodonero transgénico liberado recientemente en los E.U. [ABSTRACT FROM AUTHOR]

Insecticidal Bacillus thuringiensis Berliner (Bt) toxins produced by transgenic cotton (Gossypium hirsutum L.) plants have become an essential component of cotton pest management. Bt toxins are the primary management tool in transgenic cotton for lepidopteran pests, the most important of which is the bollworm (Helicoverpa zea Boddie) (Lepidoptera: Noctuidae) in the United States (U.S.). However, bollworm larvae that survive after consuming Bt toxins may experience sublethal effects, which could alter interactions with other organisms, such as natural enemies. Experiments were conducted to evaluate how sublethal effects of a commercial Bt product (Dipel) incorporated into artificial diet and from Bt cotton flowers impact predation from the convergent lady beetle (Hippodamia convergens Guérin-Méneville) (Coleoptera: Coccinellidae), common in cotton fields of the mid-southern U.S. Sublethal effects were detected through reduced weight and slower development in bollworm larvae which fed on Dipel incorporated into artificial diet, Bollgard II, and Bollgard 3 cotton flowers. Sublethal effects from proteins incorporated into artificial diet were found to significantly alter predation from third instar lady beetle larvae. Predation of bollworm larvae also increased significantly after feeding for three days on a diet incorporated with Bt proteins. These results suggest that the changes in larval weight and development induced by Bt can be used to help predict consumption of bollworm larvae by the convergent lady beetle. These findings are essential to understanding the potential level of biological control in Bt cotton where lepidopteran larvae experience sublethal effects. [ABSTRACT FROM AUTHOR]

Sporopollenin, as the main component of the pollen exine, is a highly resistant polymer that provides structural integrity under unfavourable environmental conditions. Tetraketone α‐pyrone reductase 1 (TKPR1) is essential for sporopollenin formation, catalyzing the reduction of tetraketone carbonyl to hydroxylated α‐pyrone. The functional role of TKPR1 in male sterility has been reported in flowering plants such as maize, rice, and Arabidopsis. However, the molecular cloning and functional characterization of TKPR1 in cotton remain unaddressed. In this study, we identified 68 TKPR1s from four cotton species, categorized into three clades. Transcriptomics and RT‐qPCR demonstrated that GhTKPR1_8 exhibited typical expression patterns in the tetrad stage of the anther. GhTKPR1_8 was localized to the endoplasmic reticulum. Moreover, ABORTED MICROSPORES (GhAMS) transcriptionally activated GhTKPR1_8 as indicated by luciferase complementation tests. GhTKPR1_8‐knockdown inhibited anther dehiscence and reduced pollen viability in cotton. Additionally, overexpression of GhTKPR1_8 in the attkpr1 mutant restored its male sterile phenotype. This study offers novel insights into the investigation of TKPR1 in cotton while providing genetic resources for studying male sterility. [ABSTRACT FROM AUTHOR]

Traditional pesticide formulations have some shortcomings, including limited efficacy and the usage of huge amounts of insecticide, which has a negative impact on the environment. Using nano‐pesticide formulations reduces the amount of pesticide applied, minimizing pest control expenses and environmental contamination. As a result, this study was conducted to develop a microemulsion formulation containing emamectin benzoate or beta‐cyfluthrin with improved morphology, droplet size, emulsion stability, and persistence of foam. Moreover to assess the efficacy of the developed microemulsion in comparison to the convention alone against the Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.) under both laboratory and field conditions. The results showed that the optimum conditions for emamectin benzoate microemulsion was 2% active ingredient, 5% (w/w) ethyl acetate, and DMF (3:2), 3.5% (w/w) Geronol ff4 and Etocas 35 (6:1), 5% (w/w) ethanol, and 86.5% (w/w) water, while for beta‐cyfluthrin, a 5.0% active ingredient, 15% (w/w) Solvesso 100 and ethyl acetate (2:1), 7.0% (w/w) Geronol ff4 and Etocas 35 (6:1), 10% (w/w) ethanol, and 68% (w/w) water. Under laboratory conditions, emamectin benzoate was more toxic than beta‐cyfluthrin to Spodoptera littoralis second and fourth instar larvae. Emamectin benzoate was more effective that beta‐cyfluthrin against Spodoptera littoralis in the field, whether as a microemulsion or a commercial product. Thus, microemulsions of tested insecticides with better formulation qualities may be more effective than traditional ones in controlling cotton leaf worm. [ABSTRACT FROM AUTHOR]

Intercropping presents an opportunity to optimise land use and resource efficiency in cotton cultivation, particularly for small and marginal farmers facing climate-related challenges and rising input costs. This study explores the potential of intercropping short-duration vegetables with cotton to transform this production system into a more economically viable and sustainable one. The study was conducted in the Cotton Department of Tamil Nadu Agricultural University in Coimbatore during the winter irrigated season, from August to January, in both 2020 and 2021. The growth, yield parameters, equivalent yield (3645 and 4234 kg ha−1), and net return (Rs. 123,434 ha−1 and Rs. 154,034 ha−1) were higher in the intercropping system with the paired row planting of Bt cotton with two rows of cluster bean. Upon comparing sole cropping and the paired row method of planting, it was found that adopting the paired row system of planting Bt cotton with two rows of cluster bean was highly profitable in all aspects of crop production. Therefore, the adoption of paired row cropping systems with compatible intercrops that promote synergistic effects on the main crop should be considered for enhancing overall productivity, as well as sustainability. [ABSTRACT FROM AUTHOR]

Simple Summary: Historically, the pesticidal Bacillus thuringiensis proteins in transgenic cotton cultivars have shown no activity on mirid pests such as the cotton fleahopper. Therefore, control options are limited to foliar applied insecticides, which are often not optimized for reducing potential yield losses. With the inclusion of the Mpp51Aa2 protein, termed ThryvOn, damage from cotton fleahopper feeding can be mitigated. While the effect of the protein has been observed in field studies, there is a limited understanding of the interaction of the protein and the insect. Therefore, the focus of this study was the use of electropenetrography to monitor the feeding behaviors of the cotton fleahopper on both ThryvOn and a non-ThryvOn cotton cultivars. We found that although attempts were made by insects to feed on ThryvOn cotton, they exhibited shorter durations of plant fluid ingestion when feeding. Additionally, the percentage of ingestion events per insect that were sustained was lower. These findings indicate potential damage to the insect gut, consistent with the known symptoms associated with the activity of Bt proteins. Prior to the recent implementation of the Mpp51Aa2 pesticidal protein (ThryvOn), transgenic cotton cultivars have historically offered no control of the cotton fleahopper (Pseudatomocelis seriatus (Reuter)). To evaluate the feeding behavior of cotton fleahoppers on ThryvOn cotton, electropenetrography (EPG) using a Giga-8 DC instrument was used to monitor the probing activity of fourth- and fifth-instar cotton fleahopper nymphs on both ThryvOn and non-ThryvOn cotton squares. Nymphs were individually placed on an excised cotton square for 8 h of EPG recording, after which resulting waveforms were classified as non-probing, cell rupturing, or ingestion. Although there were significantly more cell rupturing events per insect on ThryvOn (mean ± SEM, 14.8 ± 1.7) than on non-ThryvOn squares (mean ± SEM, 10.3 ± 1.6), there was no difference attributable to ThryvOn in the average number of ingestion events per insect. However, the average duration of ingestion events was significantly shorter on squares with ThryvOn (mean ± SEM, 509 ± 148 s) than on squares without (mean ± SEM, 914 ± 135 s). This suggests that cotton fleahoppers continued to probe despite their inability to sustain ingestion. These results provide conclusive evidence that the Mpp51Aa2 pesticidal protein affects the feeding behavior of cotton fleahopper nymphs. [ABSTRACT FROM AUTHOR]

This paper interrogates technological fix narratives on the genetically modified crop Bt cotton in India that claim to address poverty under climate change. Furthermore, I focus on the political economy of input markets as the mechanism for technology adoption and theoretically maximizing profitability for farmers. I compare these narratives to empirical reality by drawing on 94 interviews and 151 household surveys conducted in the south Indian state of Telangana, the second biggest Bt cotton producing state in India. I show how Bt cotton has been propagated as a technological climate fix crop through its technical traits of thriving in higher temperatures and adapting to particular pests in rainfed conditions relative to non-GM cotton varieties. Yet, I show how Bt cotton increases economic risks for farmers due to higher input costs, which are financed by debt relations with market intermediaries. These debt relations, which I term 'indebtedness treadmills', are intrinsically linked to droughts and rainfall climatic variability in Telangana, owing to the increasingly unreliable agroecological rainfed and semi-arid Bt cotton growing conditions. The paper therefore highlights unintended consequences of technological fix climate narratives that arise from siloing technologies from their contextual conditions of adoption to the detriment of real-world outcomes. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable agriculture, efficient water management remains crucial, with growers relying on advanced techniques for informed decision-making. Cotton yield prediction, a critical aspect of agricultural planning, benefits from cutting-edge technologies. However, traditional methods often struggle to capture the nuanced complexities of crop health and growth. This study introduces a novel approach to cotton yield prediction, leveraging the synergy between Unmanned Aerial Vehicles (UAVs) and scale-aware convolutional neural networks (CNNs). The proposed model seeks to harness the spatiotemporal dynamics inherent in high-resolution UAV imagery to improve the accuracy of the cotton yield prediction. The CNN component adeptly extracts spatial features from UAV-derived imagery, capturing intricate details related to crop health and growth, modeling temporal dependencies, and facilitating the recognition of trends and patterns over time. Research experiments were carried out in a cotton field at the USDA-ARS Cropping Systems Research Laboratory (CSRL) in Lubbock, Texas, with three replications evaluating four irrigation treatments (rainfed, full irrigation, percent deficit of full irrigation, and time delay of full irrigation) on cotton yield. The prediction revealed that the proposed CNN regression models outperformed conventional CNN models, such as AlexNet, CNN-3D, CNN-LSTM, ResNet. The proposed CNN model showed state-of-art performance at different image scales, with the R 2 exceeding 0.9. At the cotton row level, the mean absolute error (MAE) and mean absolute percentage error (MAPE) were 3.08 pounds per row and 7.76%, respectively. At the cotton grid level, the MAE and MAPE were 0.05 pounds and 10%, respectively. This shows the proposed model's adaptability to the dynamic interplay between spatial and temporal factors that affect cotton yield. The authors conclude that integrating UAV-derived imagery and CNN regression models is a potent strategy for advancing precision agriculture, providing growers with a powerful tool to optimize cultivation practices and enhance overall cotton productivity. [ABSTRACT FROM AUTHOR]

The emergence of resistance among pests to conventional pesticides underscores the necessity for substantial efforts in identifying alternatives for managing cotton pests. So the research aimed to use the photosensitizing compounds Rose Bengal, Rhodamine B, and Methylene Blue for sustainable and eco-friendly managing of cotton pests, mainly, the second instar larvae of Earias insulana. Results indicated a high efficacy of Rose Bengal when scored 1.24x10−5M and 1.26x10−4M LC50 and LC90, respectively followed by other compounds. Rose Bengal, Rhodamine B and Methylene Blue scored 2 h highest LT50 at concentrations 3x10−5M. While LT50 values were 0.30, 0.55 and 1:45 h at 1x10−4M. Rose Bengal was high effective against E. insulana larvae compared to Methylene Blue and Rhodamine B. Moreover, the findings revealed a discernible negative correlation between the concentrations applied and the necessary median lethal time for all tested compounds indicating their efficacy against E. insulana larvae. [ABSTRACT FROM AUTHOR]

In order to study the effects of different irrigation amounts on the root characteristics and yield of cotton without film mulching (abbreviated as filmless cotton) under drip irrigation in Southern Xinjiang, five irrigation amounts of filmless cotton (300, 375, 450, 525 and 600 mm, represented by W1, W2, W3, W4 and W5) and one irrigation amount of cotton with film mulching (abbreviated as filmed cotton) (450 mm, represented by WCK) were set. The effects of irrigation amount on root length density (RLD), root surface area (RSA), root average diameter (RAD), root volume (RV), root weight density (RED) and yield of filmless cotton were analyzed. The results of the two-year experiment showed the following: (1) The indexes of cotton root growth reached the maximum at the flowering and bolling stage, and the growth of soil root in the periphery (30 cm from the main root) and the lower layer (40–60 cm soil layer) reached the peak at the flowering and bolling stages, respectively; (2) The average value of root growth index of film-free cotton in each treatment was W2 > W3 > W4 > W5 and W1. The RLD of W2 and W3 increased by 19.41–106.67% and 13.66–84.22% in the peripheral and lower soil layer, and the proportion of RSA in the peripheral and middle soil layer (20–40 cm soil layer) increased by 1.64–3.41% and 0.49–4.09% compared with other treatments. The RAD, RV and RWD after W2 treatment were relatively large at various distribution points in the soil, followed by W3 treatment; (3) The average root indexes of WCK were not significantly different from those of W3, but the indexes of the lower soil layer were the smallest, at only 29.18–66.84% of the average value of the non-film mulching treatment, while the root indexes of the surface layer (0–20 cm soil layer) and the surrounding soil were larger, with an increase of 11.43–102.17% and 29.60–111.57%, respectively, compared with the non-film mulching treatment; (4) The seed cotton yield of W3 was the highest in the non-film mulching treatment, reaching 4833.25 kg·hm−2, but was still lower than that of WCK by 27.79%. Conclusion: An appropriate water deficit is conducive to root growth and increases the uniformity of its distribution in the soil layer. The irrigation amount of 375–450 mm for filmless cotton in Southern Xinjiang can promote root growth, prevent senescence and increase yield, which can be used as a reference in production. [ABSTRACT FROM AUTHOR]

Transgenic Bt cotton is effective to a high degree of, with respect to target lepidoptran bollworms, however sucking pests especially whitefly posed a serious issues in absence of bollworm in genetically modified (GM) crops. Therefore, to understand the efficacy of various biorational compounds against whitefly under non-weedy as well as weedy field conditions, studies on whitefly carried out during kharif 2018, to know the changes in number of whitefly adults as well as nymphs. Transgenic hybrid cotton variety RCH 650 was sown with a spacing of 100x45 cm and replicated four times in both non-weedy and weedy habitat. Although, standard check Dimethoate 30 EC proved it's efficacy after first and second spray in cotton crop against whitefly. Not with standing, after the application of biorational first time as spray in 29th Standard Meteoroloical Week (SMW), Nimbecidine 300 ppm was admitted as most effective in non-weedy (66.76 and 60.65% mean mortality in whitefly adult and nymph, respectively) as well as in weedy habitat that caused 56.77 and 55.54% mean mortality in adult and nymph, respectively over a period of seven days after application. Entomopathogenic fungi Verticillium lecanii found better to control whitefly adults (42.06 and 40.63%), while Metarhizium anisopliae (42.39 and 36.01%) found more effective for nymphal mortality in non-weedy as well as in weedy habitat. One and same pattern of efficacy of biorational was reconstructed against whitefly again after second application of biorational in all the treatment selected to test against whitefly. [ABSTRACT FROM AUTHOR]

Intensification in agriculture affects many insect species, including butterflies. Insect‐resistant crops, such as Bt (Bacillus thuringiensis) maize, which produces a toxin active against Lepidoptera, are an alternative to insecticide sprays. Genetically modified crops are regulated in most countries and require an environmental risk assessment. In the European Union, such assessments include the use of simulation models to predict the effects on nontarget Lepidoptera (NTL). To support the assessment of protected NTL, we extended an individual‐based, stochastic, spatially explicit mathematical model (LepiX) to include a wider range of exposure scenarios, a species‐sensitivity distribution, and an option for repeated exposure of individuals. We applied the model to transgenic maize DAS‐1507, which expresses a high concentration of Bt toxin in pollen that may be consumed by NTL larvae on their host plants nearby. Even in the most conservative scenario without repeated exposure, mortality estimates for highly sensitive species ranged from 41% to 6% at distances of 10–1000 m from the nearest maize field. Repeated exposure can cause additional mortality and thus is relevant for the overall risk assessment. Uncertainties in both exposure and ecotoxicity estimates strongly influenced the predicted mortalities. Care should be taken to include these uncertainties in the model scenarios used for decision‐making. In accordance with other modeling results, our simulations demonstrated that mean mortality may not be safe for protected species. With its high pollen expression, DAS‐1507 maize may pose risks to sensitive and protected butterfly and moth species that may be difficult to manage. High expression of Bt toxin in pollen is unnecessary for controlling target pests. Consequently, we suggest that Bt maize with high pollen expression not be cultivated in regions where protected butterflies are to be conserved. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is one of the most important insect pests affecting corn crops worldwide. Although planting transgenic corn expressing Bacillus thuringiensis (Bt) toxins has been approved as being effective against FAW, its populations' resistance to Bt crops has emerged in different locations around the world. Therefore, it is important to understand the interaction between different Bt proteins, thereby delaying the development of resistance. In this study, we performed diet-overlay bioassays to evaluate the toxicity of Cry1Ab, Cry1Ac, Cry1B, Cry1Ca, Cry1F, Cry2Aa, Cry2Ab, Vip3Aa11, Vip3Aa19, and Vip3Aa20, as well as the interaction between Cry1Ab-, Cry1F-, Cry2Ab-, and Vip3Aa-class proteins against FAW. According to our results, the LC50 values of Bt proteins varied from 12.62 ng/cm2 to >9000 ng/cm2 (protein/diet), among which the Vip3Aa class had the best insecticidal effect. The combination of Cry1Ab and Vip3Aa11 exhibited additive effects at a 5:1 ratio. Cry1F and Vip3Aa11 combinations exhibited additive effects at 1:1, 1:2, and 5:1 ratios. The combination of Cry1F and Vip3Aa19 showed an antagonistic effect when the ratio was 1:1 and an additive effect when the ratio was 1:2, 2:1, 1:5, and 5:1. Additionally, the combinations of Cry1F and Vip3Aa20 showed antagonistic effects at 1:2 and 5:1 ratios and additive effects at 1:1 and 2:1 ratios. In addition to the above combinations, which had additive or antagonistic effects, other combinations exhibited synergistic effects, with variations in synergistic factors (SFs). These results can be applied to the establishment of new pyramided transgenic crops with suitable candidates, providing a basis for FAW control and resistance management strategies. [ABSTRACT FROM AUTHOR]

The expression of Bacillus thuringiensis (Bt) toxins in transgenic cotton confers resistance to insect pests. However, it has been demonstrated that its effectiveness varies among cotton cultivars and different tissues. In this study, we evaluated the expression of Bt protein in 28 cotton cultivars and selected 7 cultivars that differed in Bt protein expression for transcriptome analysis. Based on their Bt protein expression levels, the selected cultivars were categorized into three groups: H (high Bt protein expression), M (moderate expression), and L (low expression). In total, 342, 318, and 965 differentially expressed genes were detected in the H vs. L, M vs. L, and H vs. M comparison groups, respectively. And three modules significantly associated with Bt protein expression were identified by weighted gene co-expression network analysis. Three hub genes were selected to verify their relationships with Bt protein expression using virus-induced gene silencing (VIGS). Silencing GhM_D11G1176, encoding an MYC transcription factor, was confirmed to significantly decrease the expression of Bt protein. The present findings contribute to an improved understanding of the mechanisms that influence Bt protein expression in transgenic cotton. [ABSTRACT FROM AUTHOR]

Nitrogen plays a crucial role in cotton growth, making the precise diagnosis of its nutrition levels vital for the scientific and rational application of fertilizers. Addressing this need, our study introduced an EMRDFC-based diagnosis model specifically for cotton nitrogen nutrition levels. In our field experiments, cotton was subjected to five different nitrogen application rates. To enhance the diagnostic capabilities of our model, we employed ResNet101, MobileNetV2, and DenseNet121 as base models and integrated the CBAM (Convolutional Block Attention Module) into each to improve their ability to differentiate among various nitrogen levels. Additionally, the Focal loss function was introduced to address issues of data imbalance. The model's effectiveness was further augmented by employing integration strategies such as relative majority voting, simple averaging, and weighted averaging. Our experimental results indicated significant accuracy improvements in the enhanced ResNet101, MobileNetV2, and DenseNet121 models by 2.3%, 2.91%, and 2.93%, respectively. Notably, the integration of these models consistently improved accuracy, with gains of 0.87% and 1.73% compared to the highest-performing single model, DenseNet121FC. The optimal ensemble model, which utilized the weighted average method, demonstrated superior learning and generalization capabilities. The proposed EMRDFC model shows great promise in precisely identifying cotton nitrogen status, offering critical insights into the diagnosis of crop nutrient status. This research contributes significantly to the field of agricultural technology by providing a reliable tool for nitrogen-level assessment in cotton cultivation. [ABSTRACT FROM AUTHOR]

Cotton is one of the ancient and most important commercial crops next only to food grains and is the principal raw material for a flourishing textile industry. Among important diseases, Alternaria blight mainly infect the leaf on which small, dull to dark brown, circular or irregular shaped spots appear, varying in diameter from 0.5 to 10 mm. There is a need to understand different aspects of the major fungal foliar pathogen Alternaria spp. with respect to its pathogenic and genetic variability since not much work has been done on these aspects in the past. Alternaria blight infected samples were collected from different fields of Northern Karnataka region and morphological identification was confirmed. Total genomic DNA from fungal isolates were extracted by following CTAB method. Molecular characterization of the pathogen was performed by using universal fungal primers ITS1 and ITS4. DNA amplicon was observed at the region of 400 to 600 bp. Based on the National Centre for Bioinformatics (NCBI) blast programme (Basic local alignment search tool) sequence comparison, the isolates were confirmed as Alternaria species. [ABSTRACT FROM AUTHOR]

Upon acquisition of persistent circulative viruses such as poleroviruses, the virus particles transcytose through membrane barriers of aphids at the midgut and salivary glands via hemolymph. Such intricate interactions can influence aphid behavior and fitness and induce associated gene expression in viruliferous aphids. Differential gene expression can be evaluated by omics approaches such as transcriptomics. Previously conducted aphid transcriptome studies used only one host species as the source of virus inoculum. Viruses typically have alternate hosts. Hence, it is not clear how alternate hosts infected with the same virus isolate alter gene expression in viruliferous vectors. To address the question, this study conducted a transcriptome analysis of viruliferous aphids that acquired the virus from different host species. A polerovirus, cotton leafroll dwarf virus (CLRDV), which induced gene expression in the cotton aphid, Aphis gossypii Glover, was assessed using four alternate hosts, viz., cotton, hibiscus, okra, and prickly sida. Among a total of 2,942 differentially expressed genes (DEGs), 750, 310, 1,193, and 689 genes were identified in A. gossypii that acquired CLRDV from infected cotton, hibiscus, okra, and prickly sida, respectively, compared with non-viruliferous aphids that developed on non-infected hosts. A higher proportion of aphid genes were overexpressed than underexpressed following CLRDV acquisition from cotton, hibiscus, and prickly sida. In contrast, more aphid genes were underexpressed than overexpressed following CLRDV acquisition from okra plants. Only four common DEGs (heat shock protein, juvenile hormone acid O-methyltransferase, and two unannotated genes) were identified among viruliferous aphids from four alternate hosts. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations indicated that the acquisition of CLRDV induced DEGs in aphids associated with virus infection, signal transduction, immune systems, and fitness. However, these induced changes were not consistent across four alternate hosts. These data indicate that alternate hosts could differentially influence gene expression in aphids and presumably aphid behavior and fitness despite being infected with the same virus isolate. [ABSTRACT FROM AUTHOR]

Introduction: Excessive application of nitrogen fertilizer in cotton field causes soil and water pollution as well as significant increase of aphid population. Reasonable fertilization is an important approach to improve agricultural production efficiency and reduce agriculture-derived pollutions. This study was aimed to explore the effects of nitrogen fertilizer on the Bt cotton physiological characteristics and the growth and development of A. gossypii, a sap-sucking cotton pest. Methods: Five different levels of Ca(NO3)2 (0.0 g/kg, 0.3 g/kg, 0.9 g/kg, 2.7 g/kg and 8.1 g/kg) were applied into vermiculite as nitrogen fertilizer in order to explore the effects of nitrogen fertilizer on the growth and development of Bt cotton and aphids. Results: The results showed that the medium level of nitrogen fertilizer (0.9 g/kg) effectively facilitated the growth of Bt cotton plant and suppressed the population expansion of aphids, whereas high and extremely high nitrogen application (2.7 and 8.1 g/kg) significantly increased the population size of aphids. Both high and low nitrogen application benefited aphid growth in multiple aspects such as prolonging nymph period and adult lifespan, enhancing fecundity, and improving adult survival rate by elevating soluble sugar content in host Bt cotton plants. Cotton leaf Bt toxin content in medium nitrogen group (0.9 g/kg) was significantly higher than that in high (2.7 and 8.1 g/ kg) and low (0.3 g/kg) nitrogen groups, but Bt toxin content in aphids was very low in all the nitrogen treatment groups, suggesting that medium level (0.9 g/kg) might be the optimal nitrogen fertilizer treatment level for promoting cotton seedling growth and inhibiting aphids. Discussion: Overall, this study provides insight into trophic interaction among nitrogen fertilizer levels, Bt cotton, and cotton aphid, and reveals the multiple effects of nitrogen fertilizer levels on growth and development of cotton and aphids. Our findings will contribute to the optimization of the integrated management of Bt cotton and cotton aphids under nitrogen fertilization. [ABSTRACT FROM AUTHOR]

Poultry litter (PL) is known to have residual effects on crop productivity long after applications cease. Whether this advantage is greater if applied by subsurface vs. surface broadcast is unknown. The objective of this study was to determine whether the residual benefit of PL to corn and cotton production is greater if applied in subsurface bands vs. surface broadcast and identify PL components contributing to this effect. The residual effect of PL applied by the two methods or synthetic nitrogen (sN) at seven plant available N rates (0–292 kg ha−1 yr−1) in 2014–2015 was tested on corn and cotton in 2016–2019. Corn was grown without applying PL or sN in 2016, and cotton was grown in 2017–2019 after applying 90 kg ha−1 yr−1 sN to all plots. Corn produced 40% greater grain and cotton produced 29% more lint yield due to residuals from PL than sN. Residuals from PL distinctly increased cotton leaf K over sN regardless of the method of application. Corn and cotton yield benefits from PL residual were greater if applied by subsurface banding vs. surface broadcast. This difference diminished with time. The overall results show PL components persist in the soil for up to 4 years and affect corn and cotton production, but this persistence is greater if the PL is applied by subsurface banding. This study identified K as the key PL nutrient that persisted in the soil and benefited cotton yield 4 years after the last application. [ABSTRACT FROM AUTHOR]

Fall armyworm (FAW, Spodoptera frugiperda) is a polyphagous and migratory lepidopteran pest insect in field crops and is notoriously invasive worldwide. In large portions of the Americas, its populations are managed using transgenic maize or cotton varieties producing insecticidal proteins from Bacillus thuringiensis (Bt), primarily Vip3Aa pyramided with Cry Bt proteins. We determined the susceptibility of FAW field populations from locations pressured with such maize hybrids for over five years. We used time–mortality bioassays with F1 third-instar larvae of six geographically distinct populations collected in maize fields of a tropical agricultural region encompassing four Brazilian states. We maintained the neonate progeny from the field populations on an artificial diet until the third instar, and then determined their survival curves on the foliage of three Vip3Aa/Cry-producing Bt maize hybrids. Death of the mid-size, third-instar FAWs occurred relatively rapidly, with larval mortality rates reaching 98–100% in less than five days regardless of Bt maize hybrid. However, median survival time (ST50) for the larvae differed among the populations, with the lowest and highest ST50 values occurring for PI-Cr (42 h, 1.75 d) and PI-Ur populations (66–90 h, 2.75–3.75 h), respectively. Therefore, the F1 third-instar larvae of FAW populations were largely susceptible to Vip3Aa/Cry-producing maize foliage, and the most contrasting susceptibility occurred in the insects from Piauí state, Brazil. These results indicate that progeny of FAWs from areas highly pressured with Vip3Aa/Cry Bt maize hybrids are killed on maize foliage producing Vip3Aa and Cry Bt proteins despite field reports of increased leaf damage by the larvae in some locations. This research informs decision making for Bt-crop resistance management by producers, technicians, and researchers in local, regional, and world agriculture. [ABSTRACT FROM AUTHOR]

Anthonomus grandis Boheman (Coleoptera: Curculionidae) is comprised of two subspecies: the boll weevil (A. g. grandis) and the thurberia weevil (A. g. thurberiae). The thurberia weevil is generally regarded as a non-pest variant of the species, whereas the boll weevil is an important economic pest of commercial cotton. In the USA, a nationwide eradication program has been largely successful against the boll weevil, but reintroductions of eradicated zones remain a threat. In 2015, A. grandis was trapped in the functionally eradicated Winter Garden growing region in Texas, where it had not been found since 2012. Weevils established in the area and triggered a multi-year, multi-million-dollar mitigation effort. In 2017, the species was trapped in Hidalgo County, New Mexico, another area where it had been previously eradicated. In this study, we obtained specimens from both trapping events and used double digest restriction site-associated DNA sequencing to obtain genetic data in homology with previously published A. grandis population genetic data. We conducted source tracing to match the captured weevils to previously described populations to determine a likely source population. We also compared the accuracy of the approach to other diagnostic methods currently used by the United States Department of Agriculture. The results suggested that a small founder population of weevils dispersed from the Lower Rio Grande Valley population in southern Texas and northern Tamaulipas and established in the Winter Garden. In Hidalgo Co., NM, the weevils were found to be genetically indistinct from non-pest populations of thurberia weevil associated with Arizona wild cotton (Gossypium thurberi). Thurberia weevils in Arizona remain unlikely to threaten commercial growers. Improved rapid diagnostic tools may be desirable to enable better assessment of trap captures and allow for a reduction in the application of mitigation efforts when the non-pest variant is identified. [ABSTRACT FROM AUTHOR]

There are difficulties in tracking host use by pests and mating between pests exposed to Bt selection and non-Bt hosts across landscapes. We used stable isotope analyses of sampled bulked and individual Helicoverpa armigera moths across the major cotton producing area of northwestern China to estimate contributions made by the predominant crops, Bt cotton (C3) and non-Bt corn (C4; a putative refuge). 'Effective mating' that between moths originating from cotton and the putative refuge (corn) was estimated using the isotope signal of sampled females and their spermatophores. Across the 4 years (2012–2015), substantially fewer moths were produced from putative refuges versus Bt cotton, and an asynchrony in population phenology occurred in moths originating from both sources at certain critical times. The proportion of C4 moths in bulked samples, and as individual females, was the highest during spring and autumn. Furthermore, the percentage of C4 moths originating from corn was positively correlated with its percentage in the landscape. However, mating was biased toward pairs of moths originating from the same host type. The proportion of 'effective mating' ranged from 24 to 45%, and was greatest during spring and autumn correspondingly. Our study suggests that the refuge role of corn might be overestimated in northwestern China because asynchrony of population phenology and a bias in mating toward pairs of moths that originate from host type are not being considered. Therefore, increasing the diversity of refuge crops temporally would better facilitate resistance management instead of relying on a single refuge host. [ABSTRACT FROM AUTHOR]

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Copyright of Arab Journal of Plant Protection is the property of Arab Society for Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crop growth and development is affected by intraspecies competition. This study was conducted to determine whether cotton productivity and profitability could be manipulated through planting geometry. The effects of row spacing, planting pattern, and variety on cotton fruit distribution, yield, and net returns were investigated near Bella Mina, AL, on a Decatur silt loam (fine, kaolinitic, thermic Rhodic Paleudults); Jackson, TN, on a Calhoun silt loam (fine‐silty, mixed, active, thermic Typic Glossaqualfs); Starkville, MS, on a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts); and Stoneville, MS, on a Bosket very fine sandy loam (fine‐loamy, mixed, active, thermic Mollic Hapludalfs). For both the 76‐ and 97‐cm row spacing, transitioning from a solid to a 2 × 1 skip row pattern reduced cotton lint yield by 19%. Reduced lint yield in the 2 × 1 skip row pattern was attributed primarily to a 7% decrease in the number of Zone 1 and first‐position bolls. Consequently, planting on a solid rather than skip row pattern increased net returns by 21%. Planting cotton in either 76‐ or 97‐cm rows using a solid rather than skip row pattern likely increases crop productivity and profitability across the US cotton belt. Core Ideas: Alternative cotton row spacings and patterns may improve net returns due to reduced input costs or greater yield.Regardless of row spacing, transitioning from a solid to 2 × 1 skip row pattern decreased cotton lint yield by 19%.Planting on a solid pattern rather than 2 × 1 skip row increased net returns by 21%. [ABSTRACT FROM AUTHOR]