Foliar Spray Research Articles

Antibacterial activity of high surface area zinc oxide nanoparticles for controlling black rot disease of Chinese kale

AbstractZinc oxide nanoparticles (ZnO NPs) are inorganic compounds listed as “generally recognized as safe” (GRAS) materials and have been used in plant production as well as for plant disease control. This study investigated the antibacterial efficacy of ZnO NPs with various surface areas against Xanthomonas campestris pv. campestris, assessed the effectiveness of ZnO NPs in controlling black rot disease in Chinese kale, and examined the influence of ZnO NPs application on soil bacterial communities. The results showed that ZnO NPs with high surface area effectively inhibited X. campestris pv. campestris by restraining growth and causing cell damage. Seed treatment and foliar spray application of high surface area ZnO NPs at 250 μg/mL significantly reduced the disease severity of black rot. Furthermore, in the greenhouse experiment, the soil bacterial communities in the treatment of plants applied with ZnO NPs did not differ from those in soil of nontreated plants. Therefore, ZnO NPs have the potential to serve as an alternative substance for plant disease management.

Exogenous applications of ascorbic acid improve wheat growth, physiology and yield under salinity stress via a balance in antioxidant production and ROS scavenging

ABSTRACT Ascorbic acid (AsA) improves plant tolerance against abiotic stresses, but key mechanisms of salt tolerance by its different application modes are obscure. In this study, 5 mM AsA was applied in seed priming (SP), foliar spray (FS) and medium supplementation (MS) modes to explore their comparative effectiveness in improving salinity (170 mM) tolerance in wheat (Triticum aestivum L. cv. Galaxy-2013). For SP, seeds were primed while FS and MS were administered at tillering. One set of plants was harvested 30 days after treatment to record data for growth, pigments, leaf gas exchange and water relations, as well as shoot and root osmolytes accumulation, antioxidative defence and ionic contents. Another set was harvested at ripening to measure grain yield (GY) components. Salinity stress reduced growth, photosynthesis, water relations, antioxidants defence, enhanced free amino acids, soluble sugars, free proline and glycine betaine, hydrogen peroxide and malondialdehyde. The correlations heatmap revealed positive associations among growth, physiological and GY; being stronger in MS mode. All AsA modes reduced salinity damage, but MS was highly promising. Conclusively, maintenance of a balance in reactive oxygen species dousing and antioxidant production following tissue absorption of AsA in diminishing oxidative damage is a plausible mechanism of wheat salt tolerance.

Effect of Bee Attractants on the Attraction of Apis dorsata and their Impact on Seed Yield of Niger Guizotia abyssinica (L.f.) Cass Crop

The study was conducted at the experimental farm of the PC Unit Sesame and Niger, College of Agriculture, Jawaharlal Nehru Krishi Vishwa Vidyalaya (JNKVV), located in Jabalpur, Madhya Pradesh, during the Kharif season of 2021. The primary objective of the experiment was to assess the influence of bee attractants on the attraction of Apis dorsata (giant honey bees) and their subsequent impact on the seed yield of niger crop. The experiment was designed using a Randomized Block Design (RBD) with nine treatments and three replications. This experimental setup allows for systematic testing of the effects of different bee attractants on both bee behavior and crop yield while controlling for potential sources of variation. By utilizing this design, researchers can obtain reliable data on the efficacy of various bee attractants in enhancing pollination and improving seed yield in niger crops. The results showed that the both at 10% and 50% flowering stage Apis dorsata visit was numerically the highest with flower extract of Madhuca longifolia 10% with 20.42 and 19.25 Apis dorsata/m2/5min, respectively. This was followed by rose water spray with 19.25 and 15.33 Apis dorsata/m2/5min, respectively. The population of Apis dorsata was received from the controlled condition 4.08 and 6.08 Apis dorsata/m2/5min at 10% and 50% flowering stage, respectively. This was followed by water spray 5.75 and 8.58 Apis dorsata/m2/5min at 10% and 50% flowering stage, respectively. The foliar spray of mahua flower extract and rose water 10% were found significantly superior over others in respect to record higher seed yield and recorded 6.90 q and 6.70 q/ha seed yield, respectively.

Exploring Nitric Oxide as a Regulator in Salt Tolerance: Insights into Photosynthetic Efficiency in Maize

The growing issue of salinity is a significant threat to global agriculture, affecting diverse regions worldwide. Nitric oxide (NO) serves as an essential signal molecule in regulating photosynthetic performance under physiological and stress conditions. The present study reveals the protective effects of different concentrations (0–300 µM) of sodium nitroprusside (SNP, a donor of NO) on the functions of the main complexes within the photosynthetic apparatus of maize (Zea mays L. Kerala) under salt stress (150 mM NaCl). The data showed that SNP alleviates salt-induced oxidative stress and prevents changes in the fluidity of thylakoid membranes (Laurdan GP) and energy redistribution between the two photosystems (77K chlorophyll fluorescence ratio F735/F685). Chlorophyll fluorescence measurements demonstrated that the foliar spray with SNP under salt stress prevents the decline of photosystem II (PSII) open reaction centers (qP) and improves their efficiency (Φexc), thereby influencing QA− reoxidation. The data also revealed that SNP protects the rate constants for two pathways of QA− reoxidation (k1 and k2) from the changes caused by NaCl treatment alone. Additionally, there is a predominance of QA− interaction with plastoquinone in comparison to the recombination of electrons in QA QB− with the oxygen-evolving complex (OEC). The analysis of flash oxygen evolution showed that SNP treatment prevents a salt-induced 10% increase in PSII centers in the S0 state, i.e., protects the initial S0–S1 state distribution, and the modification of the Mn cluster in the OEC. Moreover, this study demonstrates that SNP-induced defense occurs on both the donor and acceptor sides of the PSII, leading to the protection of overall photosystems performance (PIABS) and efficient electron transfer from the PSII donor side to the reduction of PSI end electron acceptors (PItotal). This study clearly shows that the optimal protection under salt stress occurs at approximately 50–63 nmoles NO/g FW in leaves, corresponding to foliar spray with 50–150 µM SNP.

The Alteration in Physiological Status, Growth and Essential Oil Profile of French Marigold (Tagetes patula L.) Owing to Seaweed Extract and Salicylic Acid Application

Abstract Purpose Medicinal plants show a relevant importance in human life and health. The use of natural substances in crop management is not only significant for the plant healthy growth and yield, but also for obtaining safe products. The study aimed to examine the effect of seaweed extract (SW) as a natural source of nutrition and salicylic acid (SA) on plant health, physiology and essential oil profile of French marigold (Tagetes patula L.). Methods Three levels of salicylic acid, SA50, SA100 and SA200, (50, 100, and 200 mg L− 1) and three levels of seaweed extract, SW2, SW4 and SW6 (2.0, 4.0, and 6.0 ml L− 1), in comparison with control treatment (tap water) were applied as foliar sprayings. The seven treatments were arranged in randomized complete block design and were replicated thrice in two growing seasons (2020 and 2021). Results Findings pointed out that SA200 increased plant height, branches number plant− 1, stem diameter, leaf area, leaves number plant− 1, plant fresh weight, and plant dry weight by 32.9, 112.2, 59.2, 34.4, 44.3, 33.0 and 56.9% (averages of the two seasons), respectively, compared to the control treatment (tap water). SW6 increased carotenoids content by 34.8 and 46.4% in 2020 and 2021 seasons, respectively. Salicylic acid at the rate of 200 mg L− 1 along seaweed extract at 6 ml L− 1 gave the highest values of total sugars and free amino acids. SA200 alone recorded the maximal value of peroxidase activity surpassing the other treatments. SW6 possessed the greatest essential oil content in both seasons, statistically equaling SA200 in the first season. Huge variations in essential oil profile were recorded under the tested trial treatments. Conclusion It could be concluded that salicylic acid and seaweed extract foliar application unveiled their involvement in diverse physiological and developmental responses; pigment formation, enzyme activities, flower induction, nutrient uptake, essential oil metabolism, and overall plant growth and development. It is recommended to use the highest concentrations of the tested substances (SA at 200 mg L− 1 or SW at 6.0 ml L− 1) for achieving distinctive improvements in physiological responses of French marigold plant.

The influence of foliar macronutrient on growth and yield of sweet corn grown in Rengam and Rasau soil series under greenhouse conditions

The purpose of this study was to determine the effects of different rates of macronutrients as a foliar applications on growth and yield performance of sweet corn cultivated in Rengam and Rasau soil series of Malaysia under greenhouse condition. The study comprised five treatments of macronutrient fertilization as a foliar application (0, 25, 50, 75 and 100 % NPK). The plant height, stem width, leaf number, leaf area and cob height of sweet corn grown in Rengam soil series were significantly influenced by foliar macronutrient application. Notably, a rise in cob weight of sweet corns cultivated in Rasau soil series was observed at the 75 % rate, reaching 75 g, compared to 68 g for sweet corn grown in Rengam soil series. The foliar application of 100 % NPK resulted in the highest total leaf area at 252.92 cm2 compared to all other treatments. Regarding the cob fresh weight and dry matter content of sweet corn cultivated in the Rasau soil series, significant improvement noted with the 75 % NPK treatment, however plants grown in the Rengam soil series and treated with 75 % NPK as a foliar application did not exhibit significant effects. The concentrations of Fe and Mn in the corn stem from both soil series significantly increased with macronutrients foliar application. In the corn leaves grown in Rengam soil series, the concentration of nutrients was significantly influenced by the rate of NPK used as a foliar application in this study. Notably, the increased of Ca content in the treated leaves was significantly higher compared to control plants. Additionally, the contents of P, K, Cu and Zn in the corn flower of the plants in the Rengam soil series were significantly elevated in treated plants compared to untreated ones. Conclusively, based on this greenhouse study, it can be inferred that two foliar sprays of macronutrient solution at rates of 75 % and 100 % NPK greatly enhanced the growth, yield and nutrient contents of sweet corn cultivated in the Rengam and Rasau soil series.

The Coupling Effects of PGPR Inoculation and Foliar Spraying of Strigolactone in Mitigating the Negative Effect of Salt Stress in Wheat Plants: Insights from Phytochemical, Growth, and Yield Attributes

Salt stress has detrimental effects on wheat plants at several physiological, biochemical, and molecular levels. This stress leads to suppressed growth, reduced grain yield, and poor quality of harvested grains. However, two approaches have shown promise for improving wheat salt tolerance: using a synthetic strigolactone analog called GR24 and applying plant growth-promoting rhizobacteria (PGPR). GR24 plays a vital role in regulating plant growth and development and in defense against various stresses. Conversely, PGPR are beneficial bacteria that colonize the rhizosphere of plants and promote their growth through multiple mechanisms. In our study, we investigated the effects of salinity on the growth and yield traits of two different wheat cultivars and explored the combined role of PGPR and GR24 in mitigating the impact of salt stress. We created three different salinity levels using NaCl in pots (original, 5 dS m−1, and 10 dS m−1) and inoculated wheat seeds with a salt-tolerant Bacillus velezensis UTB96 strain. In addition, we applied 10 μM GR24 via foliar application during the pollination stage. Our observations showed that salt stress negatively affected wheat’s growth, yield, and phytochemical properties compared to the control. However, both single and combined applications of PGPR and GR24 mitigated the adverse effects of salinity. The combined treatment had a more substantial impact than either alone in inducing and improving biochemical and ionic characteristics. These included decreasing Na+ content in both leaves and roots, and EL, H2O2, and MDA content in leaves while increasing K+ content in both leaves and roots, growth and yield-related traits, RWC, chlorophyll pigments, total protein, soluble sugar, starch, proline, GB, and antioxidant enzyme activity (APX, POX, and CAT) of leaves. In conclusion, integrating PGPR and GR24 can efficiently induce salt tolerance and improve plant growth under stressed conditions. This combined approach has the potential for broad applicability in supporting plant growth in the presence of salt stress.

Bacterial blight: Once a menacing disease of cotton in India, now tamed and fading from research spotlight

AbstractBacterial blight, incited by Xanthomonas citri pv. malvacearum (Xcm), is historically one of the most devastating diseases of cotton globally. In India, the initial documentation of the disease dates back to 1918 and it assumed a great magnitude after 1947, primarily triggered by cultivation of tetraploid cotton, as the earlier cultivated indigenous diploid cotton was naturally resistant to the pathogen, and became widespread during the 1970s. Among 20 races of bacterial blight pathogen documented at global level, Race 18 is the most virulent one and prominent in India. The pathogen inflicts damage at all crop stages, beginning with seedlings. The disease caused regular yield losses of 30%–35% in India and had become a formidable adversary to cotton cultivation in the country; however, over the years its appearance diminished. Much larger gains were apparently achieved when disease was managed with a combination of seed treatment, foliar sprays and bio‐agents. Furthermore, extensive breeding programmes led to development of resistant cultivars, which proved instrumental in managing the disease. The disease exhibited a sharp decline from the beginning of the 21st century and is now no longer a chronic problem in India. This comprehensive review attempts to provide insight into the dynamic nature of bacterial blight threatening cotton cultivation in India during the last century and the underpinning multifaceted research efforts that paved the way for countering the disease. An attempt is made to discuss the qualitative and quantitative studies on genetics of bacterial blight for facilitating the breeding programmes.

Influence of Organic Nutrients on Growth and Yield of Summer Greengram (Vigna radiata)

Greengram ( Vigna radiata L. ), commonly called as mungbean is an important pulse crop grown mainly in Zaid and Kharif season in India. Organic farming is one of the sustainable farming practices that can overcome the harmful effects of chemical farming and provides quality production. A field experiment was conducted during Zaid, 2023 to study the “Effects of organic nutrients on growth and yield of summer Greengram (Vigna radiata L.)” at SHUATS Model Organic Farm, Department of Agronomy, SHUATS, Prayagraj (U.P). The experiment was laid out in a randomized block design with nine treatments replicated thrice. The treatment consisted of 3 different solid manures i.e. Farm Yard Manure, Vermicompost, Goat manure and 3 different liquid manures i.e. Fish Amino Acid, Panchagavya and Seaweed (Kappaphycus alvarezii) sap. The experimental field soil was sandy loam in texture, moderately basic in reaction (pH 7.8), available medium Organic Carbon (0.662 %) low in available nitrogen (249.5 kg/ha), and very high accessible phosphorus (38.7 kg/ha) and available potassium (240.8 kg/ha). The result showed that significantly higher growth parameters viz., plant height (42.09 cm), number of nodules (22.22/plant), dry weight (19.35g/plant) and yield attributes such as effective pod/plant (11.05), seed/pod (9.68), test weight (38.41 g), seed yield (1643.54 kg/ha) and stover yield (3023.55 kg/ha) were observed with application 5 t/ha FYM and foliar spray of 7.5 % K sap (T9). Highest net return (Rs. 100383.30/ha) and benefit cost ratio (1.84) was also recorded in the same treatment. This concludes that application of 5 t/ha FYM along with foliar spray of 7.5 % K sap at 15 and 30 DAS performed better in terms of yield and economic returns.

Zinc Oxide Nanoparticles Alleviate Salt Stress in Cotton (Gossypium hirsutum L.) by Adjusting Na+/K+ Ratio and Antioxidative Ability

Soil salinization poses a threat to the sustainability of agricultural production and has become a global issue. Cotton is an important cash crop and plays an important role in economic development. Salt stress has been harming the yield and quality of many crops, including cotton, for many years. In recent years, soil salinization has been increasing. It is crucial to study the mechanism of cotton salt tolerance and explore diversified materials and methods to alleviate the salt stress of cotton for the development of the cotton industry. Nanoparticles (NPs) are an effective means to alleviate salt stress. In this study, zinc oxide NPs (ZnO NPs) were sprayed on cotton leaves with the aim of investigating the intrinsic mechanism of NPs to alleviate salt stress in cotton. The results show that the foliar spraying of ZnO NPs significantly alleviated the negative effects of salt stress on hydroponic cotton seedlings, including the improvement of above-ground and root dry and fresh weight, leaf area, seedling height, and stem diameter. In addition, ZnO NPs can significantly improve the salt-induced oxidative stress by reducing the levels of MDA, H2O2, and O2− and increasing the activities of major antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Furthermore, RNA-seq showed that the foliar spraying of ZnO NPs could induce the expressions of CNGC, NHX2, AHA3, HAK17, and other genes, and reduce the expression of SKOR, combined with the CBL-CIPK pathway, which alleviated the toxic effect of excessive Na+ and reduced the loss of excessive K+ so that the Na+/K+ ratio was stabilized. In summary, our results indicate that the foliar application of ZnO NPs can alleviate high salt stress in cotton by adjusting the Na+/K+ ratio and regulating antioxidative ability. This provides a new strategy for alleviating the salt stress of cotton and other crops, which is conducive to the development of agriculture.

Synergistic effect of seaweed extract and boric acid and/or calcium chloride on productivity and physico-chemical properties of Valencia orange.

Many citrus species and cultivars are grown successfully in tropical and subtropical countries, as well as in arid and semi-arid regions with low levels of organic matter and low cation exchange, resulting in lower nutrient uptake by the plant. The essential nutrients needed for citrus flowering and fruit set are limited in winter due to a reduction in transpiration rate, negatively effecting vegetative growth, flowering, yield, and fruit quality. The present investigation was carried out to assess the nutritional status, fruit yield parameters, and fruit quality of Valencia orange trees after foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations in the 2020/2021 and 2021/2022 seasons. The treatments were arranged in a split-plot design (three levels spraying seaweed extract × four levels spraying calcium chloride and boric acid and their combinations × four replicates × one tree/replicate). The results indicated that all of the characteristics measured, including leaf chlorophyll, leaf mineral contents, fruit yield parameters, fruit physical properties, and fruit chemical properties, were significantly affected by the foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations. Although all treatments increased the productivity and the physical and chemical properties of Valencia orange fruits compared to the control, a treatment of 10 g/L SW combined with 0.5 g/L boric acid and 1 g/L calcium chloride produced superior results. This ratio of SW, boric acid, and calcium chloride is therefore recommended to enhance productivity and improve the physico-chemical properties of Valencia orange for greater fruit yield.

Revolutionizing Crop Nutrition: Exploring Nano Fertilizers in Agriculture

Nutrients that have been coated or encapsulated in nanomaterials to allow for regulated release and gradual soil dispersion are known as nano fertilizers. These compounds release nutrients more slowly than the commonly used bulk fertilizers, these release nutrients that are required by plants in slow process to prevent the leaching of the nutrients. The macro elements like Nitrogen, Phosphorus and Potassium are very important to plant for growth and development. Secondary nutrients like Sulphur, Calcium and Magnesium play an important role in plants like enzyme production, plant internal development, and to get good yield. Micronutrients play an important role in maintaining plants internally. The bulk application of fertilizers leads to soil, water, and environmental pollution. The application of nano fertilizers as a foliar spray increases the absorption of nutrients and decreases environmental pollution. Nano fertilizers reduce the use of conventional bulk fertilizers, therefore reduces the production cost to growers. These are very slow release in nature so maximum nutrients are absorbed by plants. These are very highly reactive in nature so sometimes causes phytotoxicity when excess amount is applied to plant than the recommended amount. The application of nano fertilizers presents a promising avenue for sustainable agriculture, offering benefits such as controlled nutrient release, improved crop yield, and reduced environmental impact. While challenges such as phytotoxicity and dosage control must be addressed, nano fertilizers hold great potential as a transformative solution to enhance agricultural productivity while mitigating environmental degradation.

Exploring the impact of organic and inorganic amendments, with foliar application of iron nanoparticles, on cadmium stabilization and growth of maize in wastewater irrigated-soil

ObjectivesThis study addresses the critical issue of Cd contamination in agricultural soils, posing substantial risks to crop productivity and food safety. While prior pot experiment has undertook this issue on a small scale, this study aims to evaluate the efficacy of selected best soil amendments, at a large-scale field experiment. MethodologyPress mud and humic acid were applied at 0.5%, while gypsum and Fe2O3 were applied at 5 mg/kg alone and with foliar application of Fe nanoparticles at 5 mg/L. AnalysisComparative analysis with control revealed the immobilization efficiency of all amendments in descending order of effectiveness as follows: 100, 102, 104, 104, 105, 102, 105, and 105% for PM, HA, GYP, Fe, PM + Fe Nps, HA + Fe Nps, GYP + Fe Nps, and Fe + Fe Nps. Additionally, reduced growth, photosynthetic activities, and elevated levels of malondialdehyde and hydrogen peroxide, indicative of oxidative damage in control plant. FindingsApplication of these amendments with foliar spraying of Fe Nps effectively mitigates Cd toxicity in maize crops, leading to improved growth, biomass, photosynthetic pigments, and antioxidant enzyme activities. Novelty/ImprovementThese findings highlight the significance of exploring innovative approach of combining different amendments with foliar application of nanoparticles to mitigate Cd contamination and enhance soil health, thereby contributing to global efforts in ensuring food safety and security.

Construction of fungicide nano delivery platform through crystal engineering for sustainable fungal control

The adverse effects resulting from off-target pesticide application pose significant risks to both ecosystems and public health. Therefore, developing a pesticide delivery system that is straightforward, effective, and devoid of secondary pollution is crucial for environmental safety. Herein, self-assembled crystalline materials involved pyrimethanil (PYR) and organic acids were constructed by crystal engineering. These materials allowed for direct manipulation of the physicochemical properties and environmental fate of PYR by the building modules. The melting point of PYR was increased from 96.19 °C to 206.69 °C. The photostability and volatile stability were improved by 3.85-fold and 297-fold, respectively. Afterwards, these crystalline materials were prepared as nano cocrystal suspensions (NCSs) in water by the one-pot method. The PYR NCSs exhibited potent bioactivity against Botrytis cinerea and demonstrated slow-release behavior. Upon foliar spraying, the PYR NCSs exhibited desirable foliar wettability with a contact angle lower than 36°. By limiting leaching into the soil and reducing environmental pesticide exposure, PYR NCS ensured the safety of both earthworms and plants. The structure–property relationships of PYR NCSs were elucidated through intermolecular interaction analysis and theoretical calculations. Overall, the NCSs constructed by the supramolecular chemistry strategy are characterized by the simple preparation, high bioactivity, stability, no carrier, slow-release, and minimal environmental risk, which offers insight for improving the utilization and sustainable management of pesticides.

Effectiveness of manganese foliar spraying to mitigate salt stress in ornamental cabbage: Insights into morphological, physiological biochemical adaptations and mTERF gene responses

Salinity has been the subject of research for many years. However, salt stress studies on ornamental plants have increased recently. It is very important to determine the responses of bedding flowers, which are widely used in landscaping, to salt stress, and to strengthen the defense against stress. Ornamental cabbage (Brassica oleareacea L.) is widely used bedding flower in winter. The aim of this study was determining the effects of foliar application of manganese (Mn) on morphological, physiological, biochemical, and molecular parameters in ornamental cabbage ('Pigeon Purple F1′) under salt stress. Plants were irrigated with 4 different irrigation solutions which containing 0 [control], 75, 150 and 300 mM NaCl concentrations and Mn (4000 ppm) was sprayed to the leaves on 0, 7th and 14th days of the salt stress application. The application of manganese did alleviate the negative effects of salinity on shoot fresh weight and shoot dry weight in 75 mM NaCl plants. Ion leakage for 0 and 75 mM NaCl decreased with foliar spraying of Mn, but relative water content of plants did not change with Mn application. Lipid peroxidation (7.6 %) and H2O2 (hydrogen peroxide) (21.3 %) contents increased with Mn foliar spraying. Superoxide dismutase (SOD) and peroxidase activity did not change with Mn application under salinity. The highest catalase activity obtained from 150 mM (13.81 Unit g−1 leaf) and 300 mM NaCl (16.00 Unit g−1 leaf) which treated with Mn. Root Na content was lower with Mn-treated plants when compared control plants under salt stress. Foliar spraying of Mn significantly increased the K content of the plants. Furthermore, Na/K and Na/Ca ratios which are important indicators for salt stress also decreased by Mn application under saline conditions. In addition, m TERF genes were measured by using the q-RT PCR. In most cases, mTERF expression was slightly induced by salinity, while manganese application generally led to downregulation of mTERFs.

Adenosine triphosphate alleviates high temperature-enhanced glyphosate toxicity in maize seedlings

Extracellular ATP plays a key role in regulating plants stress responses. Here, we aimed to determine whether ATP can alleviate the glyphosate toxicity in maize seedlings under high temperature by regulating antioxidant responses. Foliar spraying with 100 μM glyphosate inhibited the growth of maize seedlings at room temperature (25 °C), leading to an increase in shikimic acid accumulation and oxidative stress (evaluated via lipid peroxidation, free proline, and H2O2 content) in the leaves, all of which were further exacerbated by high temperature (35 °C). The growth inhibition and oxidative stress caused by glyphosate were both alleviated by exogenous ATP. Moreover, the glyphosate-induced antioxidant enzyme activity and antioxidant accumulation were attenuated by high temperature, while ATP treatment reversed this inhibitory effect. Similarly, qPCR data showed that the relative expression levels of antioxidant enzyme-related genes (CAT1, GR1, and γ-ECS) in maize leaves were upregulated by ATP before exposure to GLY. Moreover, high temperature-enhanced GLY residue accumulation in maize leaves was reduced by ATP. ATP-induced detoxification was attenuated through NADPH oxidase (NOX) inhibition. Higher NOX activities and O2•− production were noted in ATP-treated maize leaves compared to controls prior to GLY treatment, indicating that the extracellular ATP-induced alleviation of GLY toxicity was closely associated with NOX-dependent reactive oxygen species signalling. The current findings present a new approach for reducing herbicide toxicity in crops exposed to high temperatures.

Applying Boron by Fertigation or as a Foliar Fertilizer Is More Effective than Soil Applications in Northern Highbush Blueberry

Boron (B) is often deficient in many fruit crops, including blueberry (Vaccinium sp.). The objective of the present study was to evaluate different methods for applying B fertilizers to two commercial cultivars of northern highbush blueberry (V. corymbosum Earliblue and Aurora) in western Oregon, USA. Treatments included soil application of sodium tetraborate in early April (before bloom), foliar application of boric acid in late April (during bloom or petal fall), weekly fertigation with boric acid from April through July, and a control with no B. The plants were irrigated by drip, and the fertilizers were applied for two consecutive seasons at a total rate of 1.5 kg·ha−1 B per year. Each method of fertilizer application increased the concentration of B in the soil solution relative to the control, but fertigation was the only treatment that increased extractable soil B to the recommended level of 0.5 to 1.0 mg·kg−1 B. In terms of plant nutrition, foliar application of B was the most effective method for increasing the concentration of B in the leaves, roots, and fruit, followed by fertigation. Soil application of B, on the other hand, was relatively ineffective and, after 2 years, only increased the concentration of B in the leaves of ‘Earliblue’. Although leaf B levels were initially deficient at the site (<30 ppm B), none of the B application methods had any effect on yield, berry weight, fruit firmness, or titratable acidity of the fruit in either cultivar. However, foliar applied B resulted in higher concentrations of soluble solids in the fruit than no B or soil applied B in ‘Earliblue’, whereas B fertigation resulted in higher concentrations of soluble solids than soil applied B in ‘Aurora’. On the basis of these results, applying B by fertigation or as a foliar spray is recommended over the use of soil applications of B fertilizer in northern highbush blueberry.

Assessing the Impact of Integrated Dogwood Disease Management Practices on Labor Needs and Production Costs in Tennessee Nurseries

Early and accurate detection of diseases, and implementation of efficient disease management practices are crucial to reducing the economic impact associated with plant disease outbreaks. Based on survey responses from dogwood nursery growers in Tennessee, USA, scouting was identified as an important disease management practice adopted by a majority of growers for disease management in field-grown, container-grown, and pot-in-pot production systems. Our results show a significant positive correlation between disease severity and scouting frequency for dogwood plants grown in container and pot-in-pot production systems. Our efficiency measure is a self-rated efficacy scale perceived by the nursery growers about their existing disease management system in nursery plants. A significant positive correlation was found between the efficacy of disease management and the number of workers involved in scouting and a negative association between the worker hours spent in scouting and the grower's experience/exposure to other disease detection methods. The majority of nursery growers followed a set spray schedule between May and October, with applications scheduled every other week. In addition, our results showed significant positive correlations between efficacy and spray-related factors, such as disease severity and worker hours spent in spraying; efficacy of disease management and spraying frequency in field-grown dogwoods; and foliar spray costs and efficacy of disease management. We estimated ≈$379/acre per year average costs for dogwood disease management, which the growers find to be one of the major components of the dogwood production budget. Moving to automated systems of disease scouting and management has the potential to reduce the cost of these labor-intensive disease management practices of dogwood production.

Elicitation of salicylic acid and methyl jasmonate provides molecular and physiological evidence for potato susceptibility to infection by Erwinia carotovora subsp. carotovora

Among the range of severe plant diseases, bacterial soft rot caused by Erwinia carotovora is a significant threat to crops. This study aimed to examine the varying response patterns of distinct potato cultivars to the influence of E. carotovora. Furthermore, it seeks to highlight the potential role of salicylic acid (SA) and methyl jasmonate (MeJA) in stimulating the antioxidant defence system. We collected eight bacterial isolates from diseased and rotted tubers which were morphologically and physiologically identified as E. carotovora subsp. carotovora. We conducted a greenhouse experiment to analyse the antioxidant responses of three different potato cultivars (Diamont, Kara, and Karros) at various time intervals (2, 4, 6, 8, 12, and 24 h) after bacterial infection (hpi). We assessed the extent of disease damage by applying a foliar spray of 0.9 mM salicylic acid (SA) and 70 μM methyl jasmonate (MeJA). Inoculating with Ecc led to an increase in total phenolic levels, as well as the activities and gene expression of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POX) as time progressed. Additionally, the application of SA and MeJA resulted in a further increase relative to the diseased treatments. The Karros cultivar, unlike the Diamont and Kara cultivars, demonstrated the highest expression levels of PAL, PPO and POX through inoculation, reflecting its higher levels of activity and resistance. Furthermore, the genetic response of potato cultivars to infection at 0 hpi varied depending on their susceptibility. The examination of the rate of PAL activity upregulation following SA or MeJA stimulation clarifies the cultivars' susceptibility over time. In conclusion, the study identified E. carotovora subsp. carotovora as the most virulent isolate causing soft rot disease in potato tubers. It further revealed that the Karros cultivar displayed superior resistance with high activities and gene expression of PAL, PPO and POX, while the cv. Diamont exhibited sensitivity. Additionally, foliar exposure to SA and MeJA induced antioxidant responses, enhancing the potato plants' resistance against Ecc pathogenesis and overall plant defence.

Effect of Organic Nutrient Solutions on Growth and Yield Performances of Green Bean (<em>Phaseolus vulgaris</em> L.) in Red Yellow Podzolic Soil in Sri Lanka

Purpose: Liquid Organic Fertilizer (LOF) is one of the essential ways to add extra quantities of minor and major nutrients, plant hormones, stimulants, and other useful ingredients for soil cultivation.Research Method: The experiment was set up using a Randomized Complete Block Design (RCBD) with seven treatments and four replicates. The treatments were recommended basal and topdressing (Control T1), 5t/ha poultry manure as basal with foliar spray of 0.5% (T2), 1% (T3), 1.5% (T4) of Vermiwash, 0.5% (T5), 1% (T6), 1.5% of vegetable waste solution (T7). Vermiwash and vegetable waste solution were applied at 1st, 3rd, 5th, and 7th week after planting.Findings: The study showed that leaves per plant and number of branches per plant, plant height, number of flowers per plant, dry weight of leaves, and dry weight of stem and roots were significantly (P<0.05) increased in T2 at the 8th week after planting. The total pick yield achieved in T2 was higher than in tested treatments.Originality/ Value: This study suggests that the application of 5t/ha poultry manure with 0.5% vermiwash (T2) would be preferable for growing green beans in red-yellow podzolic soil.