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Single-boll weight (SBW) is difficult to estimate after defoliant application because canopy spectra include numerous mixed pixels from lint, soil, and senescent leaves, leading to strong background interference. Here we propose a UAV multispectral workflow that combines object-based boll extraction, spectral feature selection, and machine-learning regression to improve SBW mapping. Data were collected from a two-year drip-irrigated cotton experiment in Xinjiang, China involving four varieties evaluated under five planting densities treatments. Boll extraction was treated as a supervised object-based classification problem, and maximum likelihood, mahalanobis distance, and parallelepiped classifiers were compared. Fifteen vegetation indices were computed from the extracted boll pixels; informative features were identified using Pearson correlation and SHapley Additive exPlanations importance ranking. SBW was then estimated with ridge regression, random forest regression, and neural network regression using an independent validation dataset. Maximum likelihood consistently achieved overall accuracy above 97% with Kappa values above 0.93, outperforming the other classifiers. Indices derived from the red, red-edge, and near-infrared bands, particularly those designed to reduce soil background effects, showed the strongest relationships with SBW and ranked highest in SHAP. The best-performing model, which integrated maximum likelihood-based boll extraction with neural network regression, achieved a coefficient of determination of 0.80 and a root mean square error of 0.31 g on the validation set. Relative errors remained below 15% across different years, varieties, and planting densities. This workflow reduces background interference and enables transferable SBW spatial estimation for breeding evaluation and density and harvest management.

Evidence of practical resistance of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) to Bt cotton in the United States is debatable, supported with occasional reports of boll damage in the field. Our objective was to provide both empirical and long-term observational evidence of practical resistance by linking both in-season and end-of-season measurements of H. zea damage to pyramided Bt cotton bolls and to provide Cry1Ac diet-based bioassay data in support of these damage estimates. In-season boll damage from H. zea was highly correlated to end-of-season damaged bolls. Across North Carolina, Bt cotton fields with end-of-season bolls damaged by H. zea increased during 2016 compared to previous years. Elevated damage was coupled with an increase in field sprays targeting H. zea during 2016, but not related to an increase in H. zea abundance. Bioassay data indicated that there was a range of Cry1Ac susceptibility across the southeastern United States. Given the range of susceptibility to Cry1Ac across the southeastern United States, it is probable that resistant populations are common. Since H. zea is resistant to cotton expressing pyramided Cry toxins, the adoption of new cotton varieties expressing Vip3Aa will be rapid. Efforts should be made to delay resistance of H. zea to the Vip3Aa toxin to avoid foliar insecticide use.

During 2018–19, unusually higher incidences of inner cotton boll rot were reported in farmers’ fields from cotton growing tracts of Maharashtra. Extensive survey was conducted to investigate these instances of boll rot. An unusual emerging problem in cotton has been associated with reduced boll development and yield. Green bolls with and without any sign of damage were collected from farmers fields and dissected under aseptic conditions. Bacterial species belonging to members of Enterobacteriaceae family (facultative anaerobe) were predominately isolated from rot affected cotton bolls. Four bacterial strains isolated from four locations were identified on the basis of morphological, biochemical and molecular characterization. Pathogenicity of all the four isolates (CBR2-YTML, CBR1-JLGN, CBR2-BLDN and CBR5-JLGN) was proved by Koch’s postulates. To the best of our knowledge, this is the first report of occurrence and association of phytopathogenic bacteria Pantoea dispersa, a member of the Enterobacteriaceae family as a potential and principal pathogenic agent causing inner cotton (G. hirsutum L.) boll rots in Maharashtra state, India.

The genus Aspergillus contains several species that are important plant pathogens. Plant pathogenic Aspergillus spp. affect agricultural crops in the field as well as after harvest, often associated with corn ear rot, cotton boll rot, peanut yellow mold, black mold of onion and garlic, fruit rot on grapes, pomegranates, olives, citrus, and apples. Coffee berries and coffee beans as well as tree nuts are also frequently infected by Aspergillus spp. Some of the plant pathogenic Aspergillus spp. are also mycotoxigenic, produced mycotoxin in the plant tissues leading to contamination of agricultural products. Over the years, reports of plant diseases caused by Aspergillus in various crops have increased, suggesting they are commonly encountered plant pathogens. This review focuses on agricultural crops or cultivated plants infected by Aspergillus spp. The compilation of plant pathogenic Aspergillus spp. provides information to mycologists, particularly those involved in plant pathology and crop protection, with updated information on plant diseases caused by various species of Aspergillus. The updated information also includes the locality or location, province, state and the country. The knowledge on the prevalence and geographic distribution of plant pathogenic Aspergillus spp. is beneficial in the application of crop protection.

Increases in the frequency of higher-than-optimum air temperatures can substantially reduce cotton production. Little is known about the influence of different combinations of day/nighttime temperature on cotton flowering and boll maturation under ambient and elevated CO conditions. This study examined the impacts of air temperature variations on the morphology of cotton flowers and seed yield under air CO concentrations at 425 ppm (ambient, aCO ) and elevated at 725 ppm (eCO ) in controlled Soil-Plant Atmospheric Research (SPAR) chambers. The four temperature conditions were: optimum (OT; 33/21°C, day/night), high temperature (HT; 36/24°C, day/night), high nighttime (OT+HNT; 33/24 °C, day/night), and high day/nighttime (HT+HNT; 36/28 °C, day/night). Various reproductive and seed yield traits, as well as the phenology of the plants, differed significantly (p < 0.001) under the treatments. The boll maturation period significantly decreased in plants grown under HT+HNT, with only 39 days under aCO and 38 days under eCO compared to 47 days at OT. In the HT and OT+HNT conditions, the duration was 42 days at aCO and 46 days at eCO , as opposed to 41 and 44 days, respectively, under aCO . Furthermore, there was a significant reduction in the number of pollen grains per anther, 13% for OT+HNT, 24% for HT, and 39% for HT+HNT, relative to OT treatments. The seed cotton weight also showed a drastic decline, decreasing from 105 g plant under OT to 90 g under OT+HNT, 47 g under HT, and 12 g plant under HT+HNT conditions. In the HT+HNT environment, lint percentage and seed weight per plant were reduced by 26% and 86%, respectively, when compared to OT. The eCO did not alleviate the reductions in cotton yield caused by higher air temperature exposure. This study highlights that high air temperature induces flower abscission and anther indehiscence, while diverting biomass allocation towards vegetative organs. The resulting source-sink imbalances between vegetative and reproductive structures resulted in significant reductions in seed and lint yield and growth patterns across CO and temperature environments. These findings provide insights into cotton management strategies under future environmental scenarios.

The objective of this study was to identify a boron (B) application strategy maximizing cotton yield. In a two-year experiment across two soil types with three B application rates, B availability significantly regulated boll biomass accumulation rate in a 12–19-d post-anthesis window; B concentrations of 41–74 mg B kg−1 in leaves subtending bolls maximized boll weight; and moderate B application increased source–sink carbon flux by increasing net photosynthetic rate, sucrose biosynthesis, and phloem loading efficiency. Integrating these three findings will increase photoassimilate partitioning to reproductive sinks, boosting cotton yield and B-use efficiency.

[This corrects the article DOI: 10.3389/fpls.2022.960592.].

The boll weevil is a key pest of cotton in Central and South America. Its thermal requirements, development time, oviposition, survival, adult longevity, and sex ratio were determined under laboratory conditions, and the data were used to construct a fertility life table. Based on the results and a GIS (Geographic Information System), the R[sub.0] was estimated for different Brazilian regions and represented on a map. This information can be useful for developing strategies to manage the pest in cotton crops. The boll weevil, Anthonomus grandis grandis Boh., is the most important cotton pest in Central and South America. The biological characteristics and thermal requirements of boll weevils reared on an artificial diet were assessed at seven constant temperatures (18, 20, 22, 25, 28, 30, and 32 ± 1 °C) under laboratory conditions. These data were used to determine the ecological zoning for the pest in Brazil. The development time; oviposition period; the number of eggs produced; survival of eggs, larvae, and pupae; adult longevity; and sex ratio were recorded, and additional life table parameters were calculated. The total development duration ranged from 16.1 (32 °C) to 46.2 (18 °C) days. Temperature significantly affected the number of eggs laid per female (fecundity), with the highest number of eggs observed at 25 °C (251 ± 15.8). The parameters from the fertility life table indicated the greatest population growth at 25 °C and 28 °C. The net reproductive rate (R[sub.0] ) at these temperatures was 22.25 times higher than at 18 °C. Based on R[sub.0] and temperature, an ecological zoning of the pest was developed for Brazil. Brazilian regions with mean temperatures above 20 °C and below 30 °C are most favorable for the population growth of the boll weevil. The most suitable crop areas were found to be the north, midwest, and part of the northeast region, although the weevil can occur throughout Brazil if the host plants are available.

Estimating the boll development and boll yield from single-leaf photosynthesis is difficult as the source-sink relationship of cotton (Gossypium hirsutum L.) is complicated. As the boll-leaf system (BLS), which includes the main-stem leaf, sympodial leaf, and non-leaf organs, is the basic unit of the cotton source-sink relationship and yield formation, the concept of \"BLS photosynthesis\" is introduced in this study. We speculate that the characteristics of BLS gas exchange can more accurately reflect the photosynthetic function of the system, thus revealing the law of photosynthesis in the process of boll development. The results showed that the photosynthetic rate of single leaves measured by a BLS chamber was consistent with that measured by a standard single-leaf chamber. BLSs exhibited typical light response curves, and the shape of the curves was similar to those of single leaves. The light compensation point and respiration rate of BLSs were higher than those of single leaves, while the apparent quantum efficiency of BLSs was lower. Compared with single leaves, the duration of the photosynthetic function of BLSs was longer. Increasing plant density decreased the gas exchange rate per unit BLS more significantly under field conditions. There was a better linear correlation between the net CO2 assimilation rate, respiration rate of BLSs and boll biomass. Therefore, we think that the gas exchange of BLSs can better reveal the changes in photosynthetic function of BLSs and boll development. This provides a new basis for analyzing the mechanism and regulation of cotton yield formation.

A simple and inexpensive method that uses freshly excised green bolls (~10 d old) of cotton (Gossypium hirsutum L.) is developed for laboratory rearing of pink bollworm, Pectinophora gossypiella (Saunders). The adult females of pink bollworm preferred to lay eggs on the bracts and sometimes also on the rind of bolls, either singly or in a group of 2–3 eggs. The larvae fed and pupated within the bolls itself. The developing larvae can be removed at any stage of their development for morphometric studies, conducting bioassays, etc. The newly formed pupae can easily be removed and maintained till adult emergence. The egg hatching and adult emergence were 89.94 ± 3.61% and 92.32 ± 2.34%, respectively with a mean fecundity of 203.73 ± 38.83 per female and a mean generation time of 34.43 ± 0.61 days. All the biological parameters of pink bollworm reared by this method were reasonably comparable with literature reports on its rearing using different natural as well as artificial diets. The insect raised by this method retained its ability to infest field grown cotton. We could successfully raise up to five generations of pink bollworm by this method with the input of one labourer. This method is easily applicable and less expensive, and it would be highly useful in understanding the pink bollworm phenology mediated through alterations and or aberrations in nutritional status of its host crop i.e. cotton.