Agrochemicals

Industrial hemp (Cannabis sativa) production is complex, with strict regulatory constraints and challenges associated with a lack of labeled pesticides due to its status as a novel crop in the US. Four experiments were conducted in 2020 and 2021 to establish herbicide tolerances for hemp production in the coastal plain of Georgia, USA. Objectives included evaluating hemp response to pretransplant or posttransplant herbicides, determining if planting method influenced herbicide injury from residual preplant applied herbicides, and understanding how plastic mulch may influence hemp flower yields. When applied one day prior to transplanting, maximum hemp crop visual injury was less than 12% compared to the untreated control, with acetochlor, flumioxazin, fomesafen, pendimethalin, and norflurazon while dithiopyr, halosulfuron, isoxaben, and isoxaflutole resulted in greater than 50% injury. Posttransplant applications of S-metolachlor, acetochlor, pendimethalin, and clethodim resulted in less than 15% injury while halosulfuron, metribuzin, trifloxysulfuron, imazethapyr, and prometryn applications resulted in greater than 50% injury to plants. Preplant and posttransplant applied herbicides were found to have little effect on total tetrahydrocannabinol (THC), cannabidiol (CBD), or total cannabinoids in the dry flower after harvest. In a separate experiment, injury from halosulfuron and metribuzin was 52% to 56% less when planted with a mechanical transplanter as compared to the practice of using a transplant wheel to depress a hole in the soil followed by hand transplanting. In the final experiment, hemp dry flower yield in a non-plastic mulched (bareground) system was similar to that in a plastic mulched system. However, early season plant above-ground biomass was less in the plastic mulched system, which may have been due to elevated soil temperatures inhibiting early season growth. Full article

Using predicted potential N mineralization (PNM) from its relationship with CO₂ flush at 1 d incubation (CF) of soil samples in recommended N rates can reduce N fertilization rates for crops. This study used predicted PNM at the 0–15 cm depth to reduce N fertilization rates and examined spring wheat (Triticum aestivum L.) yields at two sites (Froid and Sidney) in Montana, USA. Cropping sequences at Froid were fall and spring till continuous spring wheat (FSTCW), no-till continuous spring wheat (NTCW1), no-till spring wheat–pea (Pisum sativum L.) (NTWP1), and spring till spring wheat–fallow (STWF). At Sidney, cropping sequences were conventional till spring wheat–fallow (CTWF), no-till spring wheat–fallow (NTWF), no-till continuous spring wheat (NTCW2), and no-till spring wheat–pea (NTWP2). Soil samples collected to a depth of 15 cm in September 2021 at both sites were analyzed for CF, PNM, and NO₃-N contents, from which the reduction in N fertilization rate (RNFA) and the amount of N fertilizer applied (ANFA) to 2022 spring wheat were determined. In April 2022, spring wheat was grown with or without predicted PNM and annualized crop yields were compared. The CF and PNM were 114–137% greater for NTWP1 than STWF at Froid and 26–80% greater for NTCW2 than CTWF and NTWF at Sidney. The reduction in N fertilization rate was 26–102% greater for NTWP1 at Froid and 8–10% greater for NTCW2 and NTWF than other cropping sequences at Sidney. Annualized crop yield was 26–60% lower for crop–fallow than continuous cropping, but was not significantly different between with or without PNM at both sites. Using PNM can significantly reduce N fertilization rates for crops while sustaining dryland yields. Full article

The food security of Lima—Peru’s capital city, which shelters over 30% of the total country’s population—depends on the food production of its nearest agricultural areas, the Chancay-Huaral and Chillón valleys, wherein agrochemicals are widely used. This study primarily aimed to determine the characteristics of pesticide use in these two valleys, located 83 and 30 km north of Lima City, respectively. A second aim was to assess whether proximity to Lima provides access to technical assistance regarding agricultural activities. A questionnaire-based survey assessing socioeconomic aspects, occupational exposure, and agrochemical-related knowledge was conducted on a sample of 102 participants (farmers and fieldworkers). The results revealed that the average age for starting to handle pesticides was 15 years, while life-long occupational-exposure averaged 30 years. Most pesticides used were organophosphates and carbamates. Personal protective equipment was not used and, therefore, dermal exposure and inhalation were major routes of intoxication. Despite their proximity to Lima, both valleys lack an official agronomic advisory agency, and this void has been occupied by agrochemical manufacturing companies and trading houses focused on increasing their sales. Based on the results, it is urgent to implement an official technical advisory service and a capacity-building program on pesticide use in Peru, as well as the implementation of measures for improved control, trade, and storage of pesticides. Simultaneously, a permanent epidemiological surveillance at the country level is needed to improve public health and to contribute to achieving the Sustainable Development Goals of the United Nations’ 2030 Agenda in Peru. Full article

Aquatic ecosystems can suffer inadvertent contamination from widely used herbicides. This study delves into the relative toxicity of 36 herbicides on green algae, exploring 11 distinct modes of action and 25 chemical structure classes. Through a 72-h algal growth inhibition test, it was found that herbicides targeting acetolactate synthase (ALS), photosystem II (PSII inhibitors), microtubule assembly, very-long-chain fatty acid (VLCFA) synthesis, and lipid synthesis exhibited high toxicity, with 72-h EC50 (half-maximal effective concentration) values ranging from 0.003 mg/L to 24.6 mg/L. Other pesticide types showed moderate to low toxicity, with EC50 values ranging from 0.59 mg/L to 143 mg/L. Interestingly, herbicides sharing the same mode of action but differing in chemical composition displayed significantly varied toxicity. For instance, penoxsulam and pyribenzoxim, both ALS inhibitors, demonstrated distinct toxicity levels. Similarly, terbuthylazine and bentazone, both PSII inhibitors, also exhibited differing toxicities. Notably, herbicides approved for rice cultivation showed lower toxicity to green algae compared to those intended for terrestrial plants. These data offer valuable insights for assessing the potential risks posed by these chemicals to aquatic organisms. Additionally, to prevent or minimize herbicide residual effects, modern management practices were reviewed to offer practical guidance. Full article

In this case study, the current situation faced by coffee growers attempting to control coffee leaf rust (Hemileia vastatrix) in Hawaii is reported. CLR is considered the most devastating disease affecting coffee crops worldwide and was detected in Hawaii in 2020. Three small coffee farms from the South Kona district of Hawaii Island were selected. The goals of this case study were to: (1) assist coffee growers in the early detection of CLR incidence, and consequently support farmers with recommendations for control, (2) record agronomic information and management practices, and (3) estimate the cost to control CLR during 2021 and 2022 seasons. Low CLR incidence (<4%) was initially observed at all farms (January–June 2021), but increased as the harvest began, ending the season (December 2021) at 77%, 21% and 6% incidence at farms 1, 2 and 3, respectively. At the end of 2022 season (December), CLR incidence reached 43%, 20% and 3% at farms 1, 2 and 3, respectively. The number of sprays per season (5–10), the type of fungicides applied (preventive, curative), the timing of sprays, the efficacy of applications and weather conditions all played a role in determining the infection rates at each farm. Effective control of CLR is possible in Hawaii if the sprays of fungicides are carried out with the right products, appropriate timing and good coverage. Full article

Apple scab incited by the ascomycete Venturia inaequalis poses a significant threat to apple cultivation, necessitating a reassessment of existing disease management strategies. Attempts to manage apple scab include diverse approaches like developing disease forecasting models and the extensive application of synthetic chemical fungicides. However, the efficacy of these methods is compromised by inconsistencies, environmental concerns, and the pathogen’s resistance, necessitating the exploration of alternative sustainable strategies. Addressing the challenges associated with apple scab management, this review strongly supports a shift towards the integration of biological control agents (BCAs). Emphasising the transformative synergy between BCAs and their bioactive secondary metabolites, we highlight their efficacy in advancing precision disease control through innovative and sustainable solutions. The review effectively presents a strong justification for the integration of BCAs and their by-products into apple scab management, offering insights into associated benefits, risks, and challenges while outlining promising prospects. Ultimately, it is expected to drive the adoption of environmentally conscious practices for effective apple scab management. Full article

This study aimed to evaluate the efficiency of air assistance associated with electrostatic spraying in terms of spray deposition and yield (Experiment 1), and the coverage and droplet density on soybean crops at different working speeds (Experiment 2). The treatments in Experiment 1 corresponded to combinations of electrostatic systems associated with air assistance at three airspeeds (21, 25, and 30 m·s⁻¹) plus a conventional treatment without electrostatic or air assistance. The treatments in Experiment 2 corresponded to three working speeds (3.3, 4.2, and 5.0 m·s⁻¹) with or without the use of an electrostatic system. All applications were performed with a self-propelled sprayer, delivering 75 L·ha⁻¹ with ATR 2.0 nozzles. A blue tracer, detectable as absorbance with a spectrophotometer, was added to the spray solution to evaluate deposition. The results indicate that an air assistance at 21 m·s⁻¹ plus electrostatic system increased the amount of spray deposited on the middle and top leaves of the plants in relation to the conventional system, with yield increments of up to 621 kg·ha⁻¹. The slowest working speed (3.3 m·s⁻¹) combined with air assistance and an electrostatic system provided the greatest spray deposition, droplet coverage, and density on the bottom leaves of soybean crops. Full article

Imidacloprid (IDP) products are applied via soil drenching in the citrus critical root zone (CCRZ) at 0–60 cm soil depth. This study aimed to determine the uptake and leaching of IDP in the CCRZ of a Florida Entisol. The treatments include: (1) a control with no IDP applied, (2) 1.6 g of active ingredient (a.i.) per tree (×2), and (3) 3.2 g a.i. per tree of IDP (×4). The treatments were applied to two trees within each experiment unit, replicated five times, and completely randomized. The IDP concentration in the Entisol was affected by the amount of water received within the sampling intervals. IDP movement in the Entisol was evident for the field trials in Fall 2021 and 2022, irrespective of the treatment. A total of 10 mm of daily irrigation was the major driver of IDP movement in Fall 2021 (September–December 2021), while 11.7 cm of cumulative rainfall plus 10 mm of daily irrigation were the major drivers for IDP in Fall 2022 (November–December 2022). The IDP uptake level by leaves was relatively low probably because of the relatively low temperature and humidity. More applications of IDP did not result in its higher uptake by citrus leaves in the Entisol. Given the persistence of IDP, there is a possibility of leaching, which could potentially contaminate the groundwater, surface water, and non-target organisms. Therefore, it is crucial to carefully manage the use of IDP in citrus production systems to mitigate the unintended environmental impacts. Full article

Pollinators play important roles in providing pollination services, maintaining biodiversity, and boosting crop production. Even though pollinators are essential to the environment and agriculture, their decline has been noted across multiple studies in the recent past. Both natural and anthropogenic factors have contributed to their decline. Much of the focus has been placed on climate change, habitat loss, pests and pathogens, and synthetic pesticides, but relatively little is known about the effects of biopesticides. Biopesticides are biological control agents derived from living organisms and are classified into three groups: microbial, biochemical, and plant-incorporated protectant-based products. Biopesticides are formulated similarly to their synthetic counterparts and are readily available and used within urban and agricultural settings by pest management experts and household residents. The general public and much scientific literature support the prevailing idea that biopesticides are environmentally safe and pollinator friendly in comparison with synthetic versions. However, such generalizations are based on studies with a few key pollinator species and may not be relevant to several other species that provide crop pollination services. Studies focused on native pollinators have shown that some biopesticides have lethal and sublethal effects. Because each biopesticide exhibits varying effects across pollinator species, it could be dangerous to generalize their non-toxicity across taxa and environmental settings. In this article, recent research in this direction is discussed. Full article

The importance of antioxidants has gained much attention due to the increase in the prevalence of various non-communicable diseases such as cancer, diabetes mellitus, and cardiovascular diseases, which occur due to excess reactive species. The widespread use of synthetic antioxidants in the food industry has raised concerns about their potential harmful effects on health. As a result, the utilization of natural antioxidants to preserve food and as a source of dietary antioxidants has gained attention. Essential oils extracted from Apiaceae family plants are an excellent source of antioxidants. In this review, research findings regarding the antioxidant activity of selected Apiaceae family members and their applications are discussed. Full article

Currently, there are no known human biomonitoring studies that concurrently examine biomarkers of dicamba and 2,4-D. We sought to compare biomarkers of exposure to herbicides in pregnant women residing in the US Midwest before and after the adoption of dicamba-tolerant soybean technology using urine specimens obtained in 2010–2012 from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (N = 61) and in 2020–2022 from the Heartland Study (N = 91). Specific gravity-standardized concentration levels for each analyte were compared between the cohorts, assuming data are lognormal and specifying values below the LOD as left-censored. The proportion of pregnant individuals with dicamba detected above the LOD significantly increased from 28% (95% CI: 16%, 40%) in 2010–2012 to 70% (95% CI: 60%, 79%) in 2020–2022, and dicamba concentrations also significantly increased from 0.066 μg/L (95% CI: 0.042, 0.104) to 0.271 μg/L (95% CI: 0.205, 0.358). All pregnant individuals from both cohorts had 2,4-D detected. Though 2,4-D concentration levels increased, the difference was not significant (p-value = 0.226). Reliance on herbicides has drastically increased in the last ten years in the United States, and the results obtained in this study highlight the need to track exposure and impacts on adverse maternal and neonatal outcomes. Full article

Recent advances in the microbial degradation of persistent organic pollutants have the potential to mitigate the damage caused by anthropogenic activities that are harmfully impacting agriculture soil ecosystems and human health. In this paper, we summarize the pollution characteristics of neonicotinoid insecticides (NNIs) in agricultural fields in China and other countries and then discuss the existing research on screening for NNI-degrading functional bacterial strains, their degradation processes, the construction of microbial consortia, and strategies for their application. We explore the current needs and solutions for improving the microbial remediation rate of NNI-contaminated soil and how these solutions are being developed and applied. We highlight several scientific and technological advances in soil microbiome engineering, including the construction of microbial consortia with a broad spectrum of NNI degradation and microbial immobilization to improve competition with indigenous microorganisms through the provision of a microenvironment and niche suitable for NNI-degrading bacteria. This paper highlights the need for an interdisciplinary approach to improving the degradation capacity and in situ survival of NNI-degrading strains/microbial consortia to facilitate the remediation of NNI-contaminated soil using strains with a broad spectrum and high efficiency in NNI degradation. Full article

Herbicide volatility and drift are serious problems for chemical weed control. The extended use of dicamba, especially due to the commercial release of dicamba-resistant crops, revealed many off-target dicamba injury issues for sensitive crops. The objective of the present study is to give information on the chemical properties and volatility of dicamba and highlight some key issues, while a systematic review of the recently reported cases is attempted. Unfortunately, the problem is increasing, with a huge majority of the injuries reported in the USA, but it is also present in many other countries. Several arable, horticultural, and perennial crops suffer from such damage. Specific measures and approaches are suggested in order to quantify, reduce, and prevent such problems, while the training of farmers and stakeholders and further research are certainly required for the optimization of the several alternative options. Full article

Sustainable crop and weed management is among the crucial challenges in the era of the EU Green Deal. The main objective of the present study was to apply an innovative approach for the rapid assessment of herbicide efficacy in maize (Zea mays) crop in four different trials during two years. Weed NDVI values were recorded at two weeks after treatment, while weed biomass and crop yield were also measured. The results revealed significant differences between the several treatments. In many cases, significant effects of herbicide application on the normalized difference vegetation index (NDVI) values and weed biomass were noticed at two weeks after treatment. Moreover, the mixture nicosulfuron + rimsulfuron + mesotrione resulted in high efficacy on the crop yield of all fields. Consequently, our approach can allow for an early prediction of the real field efficacy of several herbicides and thus act as an alert for the farmers in order to choose the most efficient herbicide, avoid applications of low efficacy and reduce the herbicide inputs. Full article

Plant probiotic bacteria are being increasingly used to maximize both the productivity and quality of field crops. Pseudomonas chlororaphis O6 (PcO6) is a plant root colonizer with probiotic activities. This bacterium produces an array of metabolites, including a group of phenazines that are functional in plant protection. The paper reports responses of PcO6 to a nonionic triblock copolymer surfactant, Pluronic F68. This Pluronic exhibits membrane “healing” activity and improves cryopreservation recovery in eukaryotic cells. The product is FDA-approved and is applied as an adjuvant in formulations used in agriculture, medicine, and biotechnology. Growth of PcO6 on lysogeny broth at 25 °C was unhindered by 0.1 and 1.0 g/L F68, reduced at 10 g/L, and with significant inhibition at 100 g/L F68; micelle formation could account for inhibited growth at higher doses. Phenazine production was not changed by F68, whereas the surfactant activity of F68 induced the spread of bacterial colonization on 0.5% agar. Exposure of cells to fluorescein-labeled F68 resulted in intense fluorescence, stable to washing, showing a direct association of the Pluronic with the bacterium. However, neither protection nor harm was found for PcO6 cells suspended in either 0.1% or 1% F68 after three freeze (−20 °C)/thaw cycles. These findings suggest that F68 could be compatible for use in agricultural formulations with little effect on probiotics such as PcO6. Full article

Trichome is a hair-like structure involved in mechanical and chemical defenses of plants against herbivorous insects. Nicotiana benthamiana, a wild tobacco plant, has well-developed glandular trichomes that secrete sugar esters with potent repellent and insecticidal properties. However, there is a lack of information about the effectiveness of trichome extract in the control of plant-sapping insects. The objective of this study was to investigate the effects of N. benthamiana trichome exudates on Bemisia tabaci MED (Gennadius) (Hemiptera: Aleyrodidae), a highly destructive insect pest that poses significant threats to both vegetable and ornamental plants globally. First, we determined the host preference and mortality of B. tabaci adults using the choice test and feeding assay towards tomato and N. benthamiana plants. B. tabaci preferred tomato over N. benthamiana plants. Second, we extracted N. benthamiana trichome exudates by washing the leaves with either water or ethanol and evaluated their oral toxicities against B. tabaci adults using a parafilm feeding chamber containing 20% sucrose solution. Oral ingestion of both extracts significantly increased mortality in a concentration-dependent manner. Oral ingestion of ethanol-washed 10% trichome extract caused >60% mortality in B. tabaci adults after 36 h. Third, trichome exudates were concentrated by drying to obtain a powder form, which was more potent in killing whiteflies than the liquid form. Oral ingestion of 1% trichome powder was completely lethal to B. tabaci within 36 h. N. benthamiana trichome exudates are highly toxic to B. tabaci through oral ingestion, suggesting that N. benthamiana can be used as a potential natural pesticide for whitefly management. Full article

Recently, the search for sustainable and environmentally friendly agrochemicals from natural origin is steadily growing. Propolis, a resinous substance collected by honeybees, well known for its diverse biological activities, has attracted the attention of scientists and farmers with its agrochemical potential in the last years. This review article aims to delve into the fascinating world of propolis and its utilization in agriculture. Here, we provide a brief overview of propolis: its chemical composition and the bioactive substances responsible for its biological properties. The effectiveness of propolis in controlling common pests and diseases that affect crops, suppressing postharvest illnesses of fruits and vegetables, stimulating plant defenses and increasing stress resistance, is reviewed. Discussion of the challenges and future perspectives related to the integration of propolis in agriculture is also one of our objectives, including chemical variability, standardization and regulatory considerations. We also focused on the latest research trends and technological advances that promise to unlock the full potential of propolis as a sustainable agricultural tool. Full article

Membrane fractionation with track-etched membranes was used to size-profile the microelement composition of water-extractable soil colloids (WESCs). The aim of the study is the element composition of narrow WESC fractions of typical chernozems in the range of 0.01–10 µm. Micro-/ultrafiltration through a cascade of track-etched polycarbonate membrane filters with pore sizes of 5, 2, 1, 0.8, 0.4, 0.2, 0.1, 0.05, 0.03, and 0.01 µm at room temperature was used. ICP–AES using direct spraying of obtained fractions without decomposition was used; Al, Ba, Cd, Cr, Cu, Fe, Mn, Si, Sr, Ti, Zn, Ca, K, Mg, Na, P, and S were found. Narrow WESC fractions differ significantly. For macro- and microelements, maximum amounts of Si, Al, Fe, and Ti and their maximum percentages are observed in fractions with sizes above 1 µm, while Ca, Mg, Mn, Cu, Zn, K, and S are accumulated more in fractions with sizes below 1 µm. The developed approach provides preparative isolation of a detailed set of narrow WESC fractions in the micrometer–nanometer range. This provides element soil profiles that reveal distinct differences and the individual character of each fraction as well as trends in changes in the mineral matrix and microelement composition with fraction size. Full article

In Benin, synthetic insecticides are the main pest control option used by farmers to protect and enhance their production. However, failures to control the target pests are often observed after application and may be related to agricultural practices or insecticide quality. The present work was designed to assess a rapid, simple, and reliable analytical method for detecting and quantifying the most commonly used insecticides (λ-cyhalothrin and acetamiprid) in Benin. The analytical standard technical grade separation was performed by gradient reversed-phase high-performance liquid chromatography on a C₁₈ stationary-phase column. The mobile phase consisted of a mixture of acetonitrile/water using a gradient flow. The flow rates were 1 and 1.4 mL·min⁻¹ for λ-cyhalothrin and acetamiprid, respectively. The analysis times were 15 and 20 min, with retention times of 2.35 and 7.94 min for λ-cyhalothrin and acetamiprid, respectively. Results reveal that most of the surveyed farmers were not educated (70% < Primary School Certificate) and were men (95%). Of the main insecticides applied by farmers, λ-cyhalothrin and acetamiprid were found to be the most technical-grade ones. Furthermore, the analysis of insecticides showed that the concentrations obtained in our study often differed from the ones mentioned on insecticide labels. The proposed method is useful for quantifying insecticides in various technical and commercial formulations with little interference from additives. Full article