Plant Injury Research Articles

Field and biochemical evaluation of glyphosate tolerant chickpea (Cicer arietinum L.) mutants developed through induced mutagenesis

Weed control in chickpea (Cicer arietinum L.) is challenging due to narrow genetic base of available germplasm and limited herbicide options. In this view, present research was focused on induced mutagenesis in chickpea for development of herbicide (glyphosate) tolerant mutants and subsequent screening under field conditions. Further, objective was to analyze the defence response and biochemical adjustments in selected glyphosate tolerant chickpea mutants. Initially, 376 chickpea mutants (M6 populations developed through EMS and gamma rays) were screened for glyphosate tolerance under filed conditions and scored on a 1 to 5 scale based on plant injury related traits. Among tested mutants, 40 were found highly tolerant (score = 5), 32 as tolerant (score = 4) and 20 as highly sensitive (score = 1) to glyphosate. Chickpea mutants with variable glyphosate tolerance also differed significantly (Tukey test, p < 0.05) in leaf biochemical profiles. For instant, lowest total oxidant status (4175.µM/g f. wt.) was detected in glyphosate tolerant mutant developed from desi chickpea genotype “D3009” using 0.3% EMS and in highly tolerant mutant (1775. µM/g f. wt.) developed from kabuli genotype “K709” using 0.2% EMS. In general, highly tolerant chickpea mutants exhibited highest antioxidant potential (SOD, POD, CAT, TAC) that contributed in glyphosate tolerance. Desi i.e. D1M1HT-2 and Kabuli i.e. KM3HT-2 type mutants with highest seed yield had maximum catalase activity (4200 Units/g f. wt and 540 Units/g f. wt.). Mutants developed from desi type genotypes were comparably superior to mutants derive from Kabuli in terms of herbicide tolerance.

Rehmannia glutinosa RgMATE35 Participates in the Root Secretion of Phenolic Acids and Modulates the Development of Plant Replant Disease.

Phenolic allelochemicals from root exudates dominate rhizosphere formation, lead to autotoxicity in plants subjected to continuous monoculture (CM) stress and induce the emergence of replant disease. However, the regulatory mechanisms governing the transport of phenolics from plant roots to the rhizosphere remain poorly understood. A potential phenolic efflux transporter from Rehmannia glutinosa, designated RgMATE35, has been preliminarily characterized. The objective of this study was to elucidate the molecular function of RgMATE35 in the secretion of phenolics and to investigate its role in the development of plant replant disease using quantitative real-time PCR (qRT-PCR), genetic transformation, HPLC-Q-TOF-MS and other analytical techniques. A tissue expression pattern analysis of RgMATE35 revealed that it is highly expressed in plant roots. Transient expression analysis confirmed the localization of the protein in plasma membranes. An assessment of the transport activity of RgMATE35 in Xenopus oocytes indicated that it plays a role in facilitating the efflux of labeled ferulic acid ([2H3]-FA) and trans-p-coumaric acid [2H6]-pCA. The results of functional studies in R. glutinosa demonstrated that RgMATE35 positively mediates the secretion of FA and pCA from plant roots into the rhizosphere. A molecular and physiological analysis of RgMATE35 transgenic plants subjected to CM stress revealed that the overexpression or repression of RgMATE35 resulted in notable changes in the degree of autotoxic injury in plants. These findings demonstrate that RgMATE35 plays a positive role in the development of replant disease through the secretion of phenolic acids from plant roots. They also provide a fundamental framework for elucidating the molecular regulatory mechanism through which MATEs regulate replant disease through the root secretion of allelochemicals.

Miliary Osteoma Cutis, Report of A Case After Plant Injury

Osteoma cutis (OC) is a rare condition characterized by the presence of bone particles within the skin. One subtype of osteoma cutis is miliary osteoma cutis (MOC), which primarily affects middle-aged women and commonly occurs on the face. Clinical features of MOC include papules and skin-colored hard nodules, similar to milia. In this case, we present a 60-year-old woman with facial skin lesions resulting from a plant injury. The diagnosis was miliary osteoma cutis, and successful surgical treatment was performed

Characterizing fluid delivery of targeted application devices for weed control

AbstractPrecision weed management in turfgrass and ornamental landscape systems is utilized to offset chemical costs, reduce nontarget plant injury, and control potential herbicide‐resistant weed escapes. Targeted application devices (TADs), sold as wands, dabbers, daubers, sponges, and so forth, are regularly marketed for use in turfgrass and ornamental landscape systems, but TAD use has been limited to nonselective herbicides due to limited information regarding their calibration and use. Five commonly utilized TADs were evaluated to test for variability in fluid output within a given device and between evaluated devices. Fluid output for all evaluated devices ranged 3.2–6.9 kL ha−1 and were higher than spray outputs typical of broadcast applications. High levels of variability were detected within and among specific devices. Variance of output from devices with large fluid reservoirs was driven by reservoir fill level, with more fluid output decreasing linearly as reservoir fill level decreased. Additionally, when airlock was not maintained during application, fluid output was ∼178% greater than when airlock was maintained. Average force, maximum force, contact time, and fluid output following 25 applications were measured from five TAD users. Contact time was highly correlated (R2 = 0.93) to fluid output, with fluid output increasing as contact time increased. Subsequent economic analysis indicated the maximum percentage weed coverage ha−1 at which TAD use is economically equivalent or less than broadcast application is 3%, 8.1%, 4.3%, and 0.1% with iron HEDTA (hydroxyethlethydiaminetriacetate), acetic acid, methiozolin, and glyphosate, respectively. These data indicate the primary sources of TAD output variability are reservoir fluid fill level, reservoir airlock, and duration of application.

A novel growth-promoting dark septate endophytic fungus improved drought tolerance in blueberries by modulating phytohormones and non-structural carbohydrates.

Drought is a significant global issue affecting agricultural production, and the utilization of beneficial rhizosphere microorganisms is one of the effective ways to increase the productivity of crops and forest under drought. In this study, we characterized a novel growth-promoting dark septate endophytes (DSE) fungus R16 derived from the blueberry roots. Hyphae or microsclerotia were visible within the epidermal or cortical cells of R16-colonized blueberry roots, which was consistent with the typical characteristics of DSE fungi. Inoculation with R16 promoted the growth of blueberry seedlings and the advantage over the control group was more significant under PEG-induced drought. Comparison of physiological indicators related to drought resistance between the inoculated and control groups was performed on the potted blueberry plants, including the chlorophyll content, net photosynthetic rate, root activities, MDA and H2O2 content, which indicated that R16 colonization mitigated drought injury in blueberry plants. We further analyzed the effects of R16 on phytohormones and non-structural carbohydrates (NSCs) to explore the mechanism of increased drought tolerance by R16 in blueberry seedlings. The results showed that except for the GA content, IAA, ZT and ABA varied significantly between the inoculated and control groups. SPS and S6PDH activities in mature leaves, the key enzymes responsible for sucrose and sorbitol synthesis, respectively, as well as SDH, SuSy, CWINV, HXK and FRK in roots, the key enzymes involved in the NSCs metabolism, showed significant differences between the inoculated and control groups before and after drought treatment. These results suggested that the positive effects of R16 colonization on the drought tolerance of blueberry seedlings are partially attributable to the regulation of phytohormone and sugar metabolism. This study provided valuable information for the research on the interaction between DSE fungi and host plants as well as the application of DSE preparations in agriculture.

Tolerance of Young Blackberries to a Selection of Preemergence Herbicides and Rates

Limited preemergence herbicides are registered for new blackberry (Rubus subgenus Rubus) plantings. This greenhouse experiment was designed to investigate the effects of a broad selection of preemergence herbicides at multiple rates on blackberry transplants. Screening was initiated Aug 2021 and repeated Mar 2022 in Fayetteville, AR, USA, in a greenhouse at the Milo J. Shult Agricultural Research and Extension Center. ‘Ouachita’ blackberry plugs were transplanted into utility pots that contained field soil and growth media treated with preemergence herbicides. After transplanting, plant height was measured from the substrate to the highest apical meristem of 25 representative plants. Initial blackberry plant heights were 13.5 and 9.2 cm in 2021 and 2022, respectively. Twenty-five treatments were evaluated, consisting of 12 preemergence herbicides at 1× and 2× field rates, and one untreated control. Herbicide treatments included diuron, flumioxazin, halosulfuron, indaziflam, mesotrione, napropamide, oryzalin, pendimethalin, rimsulfuron, S-metolachlor, simazine, and sulfentrazone applied to substrate in containers at their respective 1× or 2× field rates. Data were collected on plant height, blackberry injury ratings, internode length, leaf chlorophyll content, and destructive harvest, including leaf count, leaf dry biomass, and aboveground dry biomass. Specific leaf areas and leaf area-to-dry matter ratios were calculated. When observed, plant injury tended to increase from 7 days after treatment (DAT) until 42 DAT. Greater injury levels were observed in response to treatment with mesotrione at the 1× (78%) and 2× rates (90%), halosulfuron at the 1× rate (58%), halosulfuron at the 2× rate (68%), and diuron at the 2× rate (73%). Injury from diuron was rate dependent, with the 1× rate causing relatively low injury (19%). At both the 1× and 2× rates, flumioxazin, indaziflam, napropamide, S-metolachlor, and pendimethalin treatments exhibited similar responses to the untreated control.

UVC (254 nm) and Far UVC (222 nm) Irradiation Affects In Vitro Growth of Colletotrichum sp. Isolates and Their Infection of Detached Strawberry Leaves

Conventional ultraviolet C at 254 nm (UVC) and Far UVC at 222 nm (Far UVC) were evaluated as alternatives to fungicides for disease control. Conidia of 13 isolates of strawberry anthracnose pathogens (five Colletotrichum species in two complexes: C. acutatum and C. gloeosporioides) were uniformly dispersed onto agar and irradiated with UVC and Far UVC doses ranging from 52 to 1,248 J·m−2. After 48 h of incubation, a UVC dose of 1,248 J·m−2 and Far UVC doses from 234 to 935 J·m−2 reduced Colletotrichum colony counts to &lt;10 colonies/Petri dish. Cultures exposed to UVC light followed by 4 h of darkness had lower colony counts than cultures incubated under continuous light. This dark incubation period was not required for Far UVC to obtain optimal lethality, indicating Far UVC irradiation can be applied during the day or night and achieve similar fungal lethality. Inoculation of detached leaves of three anthracnose-susceptible strawberry cultivars with conidial suspensions of Colletotrichum spp. revealed that UV irradiation can affect development of anthracnose symptoms. Leaves receiving UVC doses of 312 and 624 J·m−2 or a Far UVC dose of 467 J·m−2 reduced anthracnose infection with little or no plant injury. A UVC dose of 1,248 J·m−2 and Far UVC doses ≥ 467 J·m−2 inflicted varying degrees of plant injury. Disease control intended to reduce the number of fungicidal applications could be developed with moderate doses of UVC and Far UVC irradiation while slowing the evolution of pesticide-resistant strains. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Evaluating the yield of surviving plants from early‐season hail damage in corn: A field survey

AbstractEconomic losses due to hailstorms across US corn fields occur every year. Hailstorms result in leaf defoliation, decreasing photosynthetic area and impairing carbon assimilation and crop yield for all corn (Zea mays L.) development stages. However, more attention is often given to stand reductions rather than damage to stems or leaf defoliation. During the 2014 growing season, a natural hail event affected many areas of eastern Nebraska. Twelve affected corn fields were surveyed and included in this study. An injury score scale (1–5) was developed based on various injury and severity levels before the V6 (6‐leaf corn growth stage) (six‐collared leaves). Scores were assigned to affected fields approximately 10–15 days after the hailstorm. At the end of the growing season, ears were harvested, and grain yield per plant was determined. The highest grain yield (p &lt; 0.05) was recorded with plants that were affected but retained a main stem in good condition, albeit defoliation was present (score 1, lowest damage category). In contrast, when the main stem was cut and the plant had poor regrowth (score 3), yields were reduced by approximately 53% compared to plants with an injury score of 1. A significant negative linear relationship (R2 = 0.63, p &lt; 0.01) between injury score and yield was observed (higher injury score from hail events resulted in lower yields). Based on these results, corn yield reduction due to plant injury from hail events before V6 should not be only attributed to stand reductions. Our findings indicate an opportunity to adjust the US evaluation standards for early‐season hail damage events in corn fields.

Cross-talk between antioxidant production and secondary metabolite biosynthesis under combined effects of ozone stress and nitrogen amendments: A case study of lemongrass

The present experiment was done to study the interactive effects of soil nitrogen (N) amendments and elevated ozone (O3) (N–O3) on a medicinal plant, lemongrass [Cymbopogon flexuosus (Steud.) (Wats.)]. The experiment used two doses of inorganic soil nitrogen (N1, recommended and N2, 1.5-times recommended dose) in open-top chambers under ambient and elevated (ambient + 15 ppb and ambient + 30 ppb) O3 conditions. To analyze various characteristics, samples were collected at 45 and 90 days after transplantation (DAT). Additionally, at 110 days after transplantation (DAT), the metabolite contents of the leaves and essential oils were analyzed. The present study aims to investigate the mechanistic approach involving the crosstalk between antioxidant production and secondary metabolite biosynthesis in lemongrass upon N–O3 interactions. The present experiment showed that N amendments can be an efficient measure to manage O3 injury in plants, along with ensuring a balance between primary and secondary metabolic pathways, thus sustaining the plant defense and production of bioactive compounds, simultaneously. Under N–O3, not only the Halliwell asada pathway was stimulated resulting in the increased activities and concentrations of antioxidant pools; the shikimate, phenylpropanoid and mevalonic acid pathways were also invigorated, producing more number and contents of secondary metabolites (SMs), compared with plants that were not treated with N doses. This study suggests that soil nitrogen amendments will improve the therapeutic qualities of lemongrass, along with the strengthening of its antioxidant machinery, upon exposure to O3 stress.

Composting Dairy Manure with Biochar: Compost Characteristics, Aminopyralid Residual Concentrations, and Phytotoxicity Effects

Aminopyralid (2-pyridine carboxylic acid, 4-amino-3, 6-dichloro-2-pyridine carboxylic acid) is an auxin herbicide that has been used widely to control broadleaf weeds in pasture and hay fields. With no post-application withdrawal time, aminopyralid absorbed into forage material can contaminate compost feed stocks such as hay, grass bedding material, and manure. Composts derived from such feed stocks raises concerns about after-effect injuries to sensitive crops by residual aminopyralids. Biochar (BC) additive may affect the composting process and immobilizes organic pollutants. This study examined the effect of composting dairy manure/sawdust 1:1 mixture containing 10 ppb (wet) of aminopyralid with 0%, 2%, 4%, and 10% (w/w) BC levels on chemical and biological characteristics of compost, residual aminopyralid concentration, and intensity of plant injury to tomato (Lycopersicon esculentum L.) plants after composting in 140 L plastic rotary drum reactors for two 6-month cycles. Biochar addition decreased organic matter degradation and intensified reduction in residual aminopyralid levels in a dose-dependent manner. Composting with BC concentrated more N, P, and K, caused mild plant injuries, and increased the above ground biomass compared to the no BC incorporation. Addition of BC for composting aminopyralid-contaminated dairy manure can increase the phyto safety level of compost while enhancing the key fertilizer values.

Detection of plant cadmium toxicity by monitoring dielectric response of intact root systems on a fine timescale.

The root dielectric response was measured on a minute scale to assess its efficiency for monitoring short-term cadmium (Cd) toxicity non-destructively. Electrical capacitance (CR), dissipation factor (DR) and electrical conductance (GR) were detected during the 24 to 168 h after Cd treatment (0, 20, 50 mg Cd2+ kg-1 substrate) in potted maize, cucumber and pea. Stress was also evaluated by measuring leaf chlorophyll content, Fv/Fm and stomatal conductance (gs) in situ, and shoot and root mass and total root length after harvest. CR showed a clear diurnal pattern, reflecting the water uptake rate, and decreased significantly in response to excessive Cd due to impeded root growth, the reduced tissue permittivity caused by accelerated lignification, and root ageing. Cd exposure markedly increased DR, indicating greater conductive energy loss due to oxidative membrane damage and enhanced electrolyte leakage. GR, which was coupled with root hydraulic conductance and varied diurnally, was increased transiently by Cd toxicity due to enhanced membrane permeability, but declined thereafter owing to stress-induced leaf senescence and transpiration loss. The time series of impedance components indicated the comparatively high Cd tolerance of the applied maize and the sensitivity of pea cultivar, which was confirmed by visible shoot symptoms, repeated physiological investigations and biomass measurements. The results demonstrated the potential of single-frequency dielectric measurements to follow certain aspects of the stress response of different species on a fine timescale without plant injury. The approach can be combined with widely used plant physiological methods and could contribute to breeding crop genotypes with improved stress tolerance.

The double life of trichomes: understanding their dual role in herbivory and herbicide resistance.

Understanding the evolutionary forces that maintain phenotypic variation in ecologically relevant traits has long been one of the central goals of evolutionary ecology. While the maintenance of variation in plant defense is most often hypothesized to be due to trait trade-offs or spatiotemporal variation in herbivore abundance, the role that heterogeneous selective agents may play on the maintenance of variation in plant defense is less examined. Trichomes are hair-like appendages on plant surfaces that can defend against multiple damaging agents such as pathogens, herbivores, and UV radiation. It is currently unknown however if conflicting selection from such heterogeneous agents of damage may act to maintain the variation observed in trichome traits. Here, we assess whether trichomes serve as an herbicide resistance trait and how it coincides with the conventionally studied defensive strategy of herbivory resistance. In a series of experiments, we exposed the annual invasive velvetleaf (Abutilon theophrasti) to glyphosate (active ingredient in "Roundup") to investigate whether trichome traits (type and density) are linked to herbicide resistance and to test whether herbicide influences selection on plant trichomes. We found that an increased proportion of branched trichomes positively impacted herbicide resistance and chewing herbivory resistance. We also found evidence that glyphosate imposes positive selection on branched trichomes in velvetleaf. Overall, our results indicate that branched trichomes can contribute to both herbicide and herbivory resistance, serving a concordant rather than conflicting role to reduce plant injury. Our findings further suggest that novel anthropogenic agents of selection can alter the composition of plant defense traits, potentially impacting trait-mediated interactions among external stressors.

The Multiple Promoting Effects of Suaeda glauca Root Exudates on the Growth of Alfalfa under NaCl Stress.

Under abiotic stress, plant root exudates can improve plant growth performance. However, studies on the effect of root exudates on the stress resistance of another plant are insufficient. In this study, root exudates (REs) were extracted from Suaeda glauca to explore their effect on alfalfa seedlings under salt stress. The results showed that the plant height and fresh weight of alfalfa significantly increased by 47.72% and 53.39% after 7 days of RE treatment at a 0.4% NaCl concentration. Under 1.2% salt stress, REs reduced the Malondialdehyde content in alfalfa by 30.14% and increased the activity of its antioxidant enzymes (peroxidase and catalase) and the content of its osmotic regulators (soluble sugar and proline) by 60.68%, 52%, 45.67%, and 38.67%, respectively. Soil enzyme activity and the abundance of soil-beneficial bacteria were increased by REs. Spearman analysis showed that urease and neutral phosphatase were related to the richness of beneficial bacteria. Redundancy analysis confirmed that urease affected the composition of the soil bacterial community. The partial least squares structural equation model (PLS-SEM) revealed that REs had a direct positive effect on alfalfa growth under salt stress by regulating the plant's injury and antioxidant systems, and the soil bacterial community had an indirect positive effect on alfalfa growth through soil enzyme activity.

Effect of hesperidin on growth, photosynthesis, antioxidant systems and uptake of cadmium, copper, chromium and zinc by Celosia argentea plants

Rapid industrialization and extensive agricultural practices are the major causes of soil heavy metal contamination, which needs urgent attention to safeguard the soils from contamination. However, the phytotoxic effects of excessive metals in plants are the primary obstacle to efficient phytoextraction. The present study evaluated the effects of hesperidin (HSP) on metals (Cu, Cd, Cr, Zn) phytoextraction by hyperaccumulator (Celosia argentea L.) plants. For this purpose, HSP, a flavonoid compound with strong antioxidant potential to assist metal phytoextraction was used under metal stress in plants. Celosia argentea plants suffered significant (P ≤ 0.001) oxidative damage due to the colossal accumulation of metals (Cu, Cd, Cr, Zn). However, HSP supplementation notably (P ≤ 0.001) abated ROS generation (O2•‒, •OH, H2O2), lipoxygenase activity, methylglyoxal production, and relative membrane permeability that clearly indicated HSP-mediated decline in oxidative injury in plants. Exogenous HSP improved (P ≤ 0.001) the production of non-protein thiol, phytochelatins, osmolytes, and antioxidant compounds. Further, HSP enhanced (P ≤ 0.001) H2S and NO endogenous production, which might have improved the GSH: GSSG ratio. Consequently, HSP-treated C. argentea plants had higher biomass alongside elevated metal accumulation mirrored as profound modifications in translocation factor (TF), bioaccumulation coefficient (BAC), and bioconcentration factor (BCF). In this context, HSP significantly enhanced TF of Cr (P ≤ 0.001), Cd (P ≤ 0.001), and Zn (P ≤ 0.01), while BAC of Cr (P ≤ 0.001), Cd (P ≤ 0.001), and Zn (P ≤ 0.001). Further, BCF was significant (P ≤ 0.05) only in plants grown under Cr-spiked soil. Overall, HSP has the potential for phytoremediation of metals by C. argentea, which might be a suitable strategy for metal-polluted soils.

Causes and preventive measures of pressure vessel accidents

The article deals with the problems of accidents and fatal injuries in hazardous production plants during the operation of pressure equipment. Extensive static data have been collected on the causes of accidents and occupational injuries in hazardous production facilities using pressure vessels. Emphasis is placed on analyzing the causes of accidents, the categories of victims and the nature of injuries, as well as on preventive measures to avoid accidents and minimize the risk of fatal injuries.

Method Development for Aminopyralid Residues Determination by Ultra-High-Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry in Straw

Straw is an important by-product of crop production. It has been widely used as a feed as well as in fruit–vegetable production due to exerting a positive impact on soil and crop health and quality in the operated areas. On the other hand, applied crop-specific herbicides throughout the production stage, like aminopyralid (AP), may lead to significant plant injuries in sensitive vegetable plantations, even in very low concentrations. This study aims to optimize a short time, minimal consumables needed, and sensitive extraction and analytical method for AP residues in straw material using LC-MS/MS. For this purpose, standard AP signal response in acetonitrile (MeCN) and 1% of formic acid (FA) in methanol (MeOH) were tested; several chromatographic separation and mass spectroscopy (MS) parameters were improved and optimized. Subsequently, two different extraction methods were performed in AP spiked straw samples, and extraction efficacies were compared. Salting-out assisted liquid–liquid extraction (SALLE) by acidified MeCN combined with final dissolution in MeOH with 1% of FA prior to the analysis was chosen as the most appropriate method for the straw matrix. This method was then used for validation and real sample test analysis. The limit of quantification (LOQ) of AP in this optimized extraction method achieved 10 ng/g straw with a recovery rate of 71% and 13% RSD. The method was also tested on field straw mulch samples and 22.54 ± 0.8 ng/g of AP was detected.

Response of cotton at different growth stages to imazapyr

Abstract A significant proportion of the forested production area in South Carolina is managed using aerial applications of imazapyr. Cotton injury from off-target movement of imazapyr has been observed in South Carolina. Field experiments were conducted twice at the Edisto Research and Education Center (EREC) in 2021 and 2022, and once at the Pee Dee Research and Education Center (PDREC) in 2022, to evaluate the response of cotton at two growth stages to imazapyr at 0.1×, 0.05×, 0.025×, 0.0125×, and 0.00625× of the normal use rate of 0.84 kg ae ha−1. Injury to cotton at the vegetative stage was 86% and 74% at 0.1× and 0.05× imazapyr rates 28 d after application (DAA). Cotton height ranged from 23 to 93 cm at all three locations. Yield at the EREC location in 2021 was reduced by 79%, 48%, and 31% at the 0.1×, 0.05×, and 0.025× rates of imazapyr, respectively. Similar reductions from imazapyr were observed at both EREC and PDREC in 2022. Injury to cotton at the reproductive stage based on visual estimates at 28 DAA ranged from 95% to 64% for the 0.1× to 0.0125× rates, respectively. Cotton height at the reproductive stage was reduced to 59% of the untreated control 28 DAA when the 0.1× rate of imazapyr was applied. Seed cotton (which included both seed and lint) yield ranged from 0 to 2,880 kg ha−1 at the three locations in both years. Seed cotton yield was lowest when imazapyr was applied at the 0.1× to 0.025× rates. Cotton exposure to imazapyr at the vegetative and reproductive growth stages resulted in plant injury, height, and yield reductions, especially at the higher rates of imazapyr. The greatest reduction in cotton growth and yield was observed after exposure at the reproductive growth stage regardless of imazapyr rate. In summary, the magnitude of cotton response to imazapyr depends on crop growth stage and imazapyr concentration at the time of exposure with the greatest impact occurring at the reproductive growth stage.

Canola inoculation with Pseudomonas baetica R27N3 under salt stress condition improved antioxidant defense and increased expression of salt resistance elements

Inoculation with growth promoting rhizobacteria (PGPR) can lessen salt salinity injury in plants by improving some physiological, biochemical, and molecular aspects. The current study aims to investigate Pseudomonas baetica R27N3 on photosynthetic capacity, and the antioxidant defense system of salt-affected canola plants (0, 100, 200,300 mM NaCl) under greenhouse conditions. Sodium concentration in inoculated canola plants was significantly decreased, whilst potassium increased through improved root architecture and relative expression of ion pump genes, such as SOS1 and KAT1. Moreover, inoculated canola plants showed higher antioxidant capacity which was evident in their higher antioxidant enzyme activity and those enzymes' higher relative gene expression. The study investigated additional physiological parameters related to enhanced antioxidant defense, including the electrolyte leakage index and malondialdehyde concentration as indicators of the stability of the plant cell plasma membrane. The plasma membrane of canola plants treated with PGPR was significantly more stable than those without the PGPR treatment. Furthermore, carotenoids and proline accumulation as non-enzymatic antioxidant solutes and total protein were increased in canola plants treated with R27N3. On the whole, these improvements coincided with increased antioxidant capacity, but all these positive effects of R27N3 were notable under 100 mM of NaCl concentration, whereas under 0 and 300 mM of NaCl concentration physiological and molecular changes between inoculated and non-inoculated canola plants were not statistically notable. Consequently, positive molecular and biochemical changes could be mediated by P.baetica R27N3 ability to clone on canola root and provide it with a decent level of macro-nutrients.

Hilling as a cultural control strategy for soybean gall midge (Diptera: Cecidomyiidae).

Soybean gall midge, Resseliella maxima Gagné, was recently identified as a new species causing significant injury to soybean and is currently found in 164 counties across 7 midwestern states (NE, IA, SD, MN, MO, ND, and KS). Infestation of soybean begins in late spring, when adults emerge from last year's soybean field. Infestation of a new soybean crop depends on the presence of fissures which start to form at the base of the soybean plant around the V2 stage. Field observations indicate that these fissures are only present below the cotyledonary nodes or in the area within 3-5 cm above the soil surface. To determine the importance of these fissures for R. maxima infestation and plant injury, hilling or the movement of the soil to cover the base of soybean plants at the V2-V3 stage was compared with the standard practice (no-hilling). Field studies were conducted at 3 sites in east-central Nebraska during the 2021 growing season. The results showed a significant reduction in the frequency of infested plants, larval number per plant, and plant injury for hilled compared to no-hill treatment. This reduction in the presence of larvae and plant injury corresponded with a significantly greater yield for hilled compared to the no-hill treatment. These results highlight the importance of fissures on soybean for R. maxima adult infestation as well as the potential for hilling to be used as a management strategy for R. maxima.

Transgenic sugarcane expressing Bacillus thuringiensis Cry1Ac protein offers new possibilities for controlling the giant borer, Telchin licus (Drury), a pest difficult to control

The giant borer, Telchin licus (Drury), is an important insect pest of sugarcane in Central and South America. This pest is difficult to control with chemical or biological control approaches due to the larvae behavior of hiding in the deepest parts of the plants. Manual scavenging and skewer killing have been the main approaches for monitoring and control of T. licus in Brazil, the world's largest sugarcane producer. Recently, Brazil launched the first commercial use of transgenic sugarcane expressing Bacillus thuringiensis (Bt) proteins to control the sugarcane borer, Diatraea saccharalis (F.), a primary insect pest of sugarcane in the Americas. In this study, five independent field/greenhouse tests were conducted to evaluate the larval survival of and plant injury by T. licus on five non-Bt and five Bt sugarcane varieties containing a single cry1Ac gene. The multiple field/greenhouse tests showed that Cry1Ac sugarcane was highly effective to control T. licus; and the high control efficiency was consistent across varieties, from immature to mature plant stages, as well as for F0 generation plants and F1 ratoons. In addition, diet-incorporated bioassays were performed to determine the susceptibility of three field-collected T. licus populations in Brazil to diet treated with purified Cry1Ac protein or with a 25-fold dilution of Cry1Ac sugarcane stalk tissue. The diet bioassays exhibited that the field T. licus populations were also susceptible to the purified Cry1Ac protein, as well as to diet treated with the 25-fold dilution of stalk tissue. The results of this study provide compelling evidence that the single-protein Cry1Ac sugarcane varieties offer new possibilities for managing the T. licus, a pest that is difficult to control with other current available technologies.