Plant Damage Research Articles

Rapid assessments of the rice brown planthopper (Nilaparvata lugens Stal) outbreak in Semarang District, Central Java: Effects of farmers’ low KAP

Rapid assessments on the outbreak of rice brown planthoppers (BPH) (Nilaparvata lugens Stal) were conducted to investigate the status of BPH populations and the causative factors behind the outbreak. These assessments served as the basis for developing a proper action program. The assessments took place in Banyubiru Sub-District, Semarang District covering four villages (Kebondowo, Rowoboni, Tegaron, Kebumen) in December 2013. We analyzed BPH data, along with information about farmers’ practices in managing pests collected through interviews conducted in January 2018 in Indramayu. Additionally, we examined data on the number of BPH-infested areas in Java from 2010 to 2020 and the stock of insecticides in Java in 2021. Simple statistical analyses were carried out. The BPH population had spread throughout Banyubiru and was present in all sampled plots. The average number of BPH eggs ranged from 115.25 to 379.65 per rice hill, while the BPH nymphs and imagoes ranged from 3.42 to 11.87 per rice hill. The relatively low nymphs to imagoes ratio might be influenced by the high BPH predator populations, which ranged from three to six individuals per rice hill. Suspected causes of BPH resistance and resurgence included the application of banned and improper insecticides, as well as the repeated use of the same insecticide active ingredients for an extended period. It is recommended to discontinue the mass spraying of insecticides to prevent further plant damage. In 2022, the Pest Control Movement has suggested replacing chemical insecticides with biological or natural pesticides. Intensive extension programs are strongly needed.

Use of Selected Chemical and Biological Insecticides to Control Lepidopteran Pests of Maize Fields in Central Côte d'Ivoire

Control of lepidopteran larvae, the main pests in maize fields, has become necessary since the appearance and spread of Spodoptera frugiperda. The study was carried out at the Institut National Polytechnique Houphouët-Boigny in Yamoussoukro (Central Côte d’Ivoire). The study aimed to determine the effectiveness of three chemical - Viper 46 EC (Acetamiprid 16 g/l and Indoxacarb 30 g/l), K-Optimal 35 EC (Lambdacyhalothrin 15 g/l and Acetamiprid 20 g/l) and Ampligo 150 ZC (Chlorantanlipol 100 g/l and Lambdacyhalothrin 50 g/l) - and one biological insecticide Bio-Elit (Azadirachtin, Salanin, Nimbin and Melandriol) on lepidopteran larvae in maize fields using a randomized complete block design with five treatments and three repetitions. Data on insect identification, plant infestation, damage, and yield were collected. Insects’ identification was based on morphology using identification keys. Plant damage was assessed by visually estimating the plant health status (unattacked and attacked plants). Grain dry weight was used to estimate field yield. The encountered maize field insects belonged to 10 orders: Heteroptera, Hymenoptera, Homoptera, Coleoptera, Diptera, Dictyoptera, Odonata, Orthoptera, Dermaptera, and Lepidoptera. Five lepidopteran pest larvae have been recorded. Three of them were classified as minor pests (Eldana saccharina, Ostrinia nubilalis, and Helicoverpa zea), one as important (Sesamia calamistis), and one as a major pest (Spodoptera frugiperda). On untreated plots, more than 76% of plants were moderately to heavily attacked. However, on treated plots, plants showed isolated to moderate attacks. Insecticide sprayings controlled pest populations, reduced damage, and increased yield. The yields obtained on untreated plots (2.26±0.21 t/ha) were lower than those on treated plots (3.29±0.11 to 3.60±0.09 t/ha). The yield increase rate ranged from 45.74 to 59.63%. The best control was recorded with Ampligo (59.63%) and Bio-Elit (50.83%) compared to Viper (49.41%) and K-Optimal (45.74%). Therefore, the alternating use of synthetic or biological insecticides, which are not very toxic for humans and the environment but are effective on insect pests, increases the effectiveness of the control and provides a positive response to the problem of pest resistance while protecting the environment.

Performance Analysis of Deep Transfer Learning Models for the Automated Detection of Cotton Plant Diseases

Cotton is one of the most important agricultural products and is closely linked to the economic development of Pakistan. However, the cotton plant is susceptible to bacterial and viral diseases that can quickly spread and damage plants and ultimately affect the cotton yield. The automated and early detection of affected plants can significantly reduce the potential spread of the disease. This paper presents the implementation and performance analysis of bacterial blight and curl virus disease detection in cotton crops through deep learning techniques. The automated disease detection is performed through transfer learning of six pre-trained deep learning models, namely DenseNet121, DenseNet169, MobileNetV2, ResNet50V2, VGG16, and VGG19. A total of 1362 images of local agricultural fields and 1292 images from online resources were used to train and validate the models. Image augmentation techniques were performed to increase the dataset diversity and size. Transfer learning was implemented for different image resolutions ranging from 32×32 to 256×256 pixels. Performance metrics such as accuracy, precision, recall, F1 Score, and prediction time were evaluated for each implemented model. The results indicate higher accuracy, up to 96%, for DenseNet169 and ResNet50V2 models when trained on the 256×256 pixels image dataset. The lowest accuracy, 52%, was obtained by the MobileNetV2 model when trained on low-resolution, 32×32, images. The confusion matrix analysis indicates the true-positive prediction rates higher than 91% for fresh leaves, 87% for bacterial blight, and 76% for curl virus detection for all implemented models when trained and tested on an image dataset of 128×128 pixels or higher resolution.

Silicic and Humic Acid Priming Improves Micro- and Macronutrient Uptake, Salinity Stress Tolerance, Seed Quality, and Physio-Biochemical Parameters in Lentil (Lens culinaris spp. culinaris).

Lentil is an important grain legume crop which is mostly grown on marginal soils that hamper its productivity. Improvement of salt tolerance in lentils is considered to be a useful strategy of utilizing salt-affected lands in an economic manner. This study was conducted to evaluate the effectiveness of seed priming using silicic acid and humic acid both seperately and in combination to improve salt stress tolerance among three different lentil varieties: IPL-316 (tolerant), PSL-9, and PDL-1 (susceptible). The concentrations and durations of treatments were standardized under the normal condition and the salinity stress condition. Salt stress hindered seedling emergence and biomass production and accelerated Na+ toxicity and oxidative damage at the seedling stage in untreated seeds. Nevertheless, chemical priming improved early seedling emergence, increased root length, shoot length, and seed vigor index I and II, and reduced the mean germination time. A significant quantitative change in biochemical parameters under normal and salinity stress conditions was observed in IPL-316,viz. Specifically, for IPL-316, the following parameters were observed (values under the normal condition and values under salt stress conditions, respectively): chlorophyll-a (16 and 13 mg/g Fw), chlorophyll-b (25 and 16 mg/g FW), total chlorophyll content (42 and 30 mg/g FW), relative leaf water content (92% and 82%), total soluble sugars (26 and 33 ug/g FW), free amino acid (10 and 7 mg/g FW), total phenol (26 and 24 mg of GAE/g FW), total protein (35 and 29 mg/g FW), carbohydrate (208 and 173 mg/g FW), superoxide dismutase (SOD) (29 and 35 unit/min./g FW), proline (0.28 and 0.32 u mol/g FW), catalase (CAT) (84 and 196 unit/mL/g FW), and peroxidase (POX) (217 and 738 unit/mL/g FW). Furthermore, histochemical analysis of H2O2 and O2-, micronutrients, and macronutrients also increased, while malondialdehyde (MDA) (0.31 and 0.47 nmol/mL FW) content decreased using silicic and humic acid priming under salt stress conditions. The combination of silicic and humic acids improved seedling growth and reduced oxidative damage in lentil plants under salt stress conditions. The combination of silicic and humic acid priming hastened seedling emergence, seed quality parameters, and biochemical parameters under salt stress over respective control. To the best of our knowledge, this is the first report of integrated chemical priming in lentils for salinity stress. In conclusion, chemical priming using a combination of silicic and humic acid performed better in terms of seed quality due to enhanced antioxidant machinery, better membrane stability and osmolyte protection, and enhanced nutrient uptake under salt stress conditions.

Novel moisture retaining dustable powder containing Steinernema abbasi effectively controls damage of subterranean termite in wheat and chickpea

The application of biocontrol agents in farm operations for pest control programs is gaining priority and preference globally. Effective delivery, infectivity of the biocontrol agents, and quality shelf-life products containing these bioagents are vital parameters responsible for the success of biopesticides under field conditions. In the present study, moisture-retaining bio-insecticidal dustable powder formulation (SaP) of Steinernema abbasi (Sa) infective juveniles (IJs) was developed and assessed for its shelf life, physicochemical profile, and bio-efficacy against subterranean termite under field conditions. Formulation exhibited free-flowing character, with pH of 6.50–7.50, and apparent density in the range 0.50–0.70 g cm−3. The bioefficacy study for two rabi seasons (2020–2021, and 2021–2022) in wheat and chickpea grown in an experimental farm heavily infested with subterranean termites (Odontotermes obesus) revealed a significant reduction in plant damage due to pest attack in formulation-treated plots, monitored in terms of relative number of infested tillers in wheat and infested plants in chickpea fields. The reduced damage to the crop caused by termite was reflected in the relative differences in the growth and yield attributes as well. The study establishes the potential of the developed product as a biopesticide suitable for organic farming and integrated pest management operations.

Comparative genomic analysis of Chryseobacterium species: deep insights into plant-growth-promoting and halotolerant capacities.

Members of the genus Chryseobacterium have attracted great interest as beneficial bacteria that can promote plant growth and biocontrol. Given the recent risks of climate change, it is important to develop tolerance strategies for efficient applications of plant-beneficial bacteria in saline environments. However, the genetic determinants of plant-growth-promoting and halotolerance effects in Chryseobacterium have not yet been investigated at the genomic level. Here, a comparative genomic analysis was conducted with seven Chryseobacterium species. Phylogenetic and phylogenomic analyses revealed niche-specific evolutionary distances between soil and freshwater Chryseobacterium species, consistent with differences in genomic statistics, indicating that the freshwater bacteria have smaller genome sizes and fewer genes than the soil bacteria. Phosphorus- and zinc-cycling genes (required for nutrient acquisition in plants) were universally present in all species, whereas nitrification and sulphite reduction genes (required for nitrogen- and sulphur-cycling, respectively) were distributed only in soil bacteria. A pan-genome containing 6842 gene clusters was constructed, which reflected the general features of the core, accessory and unique genomes. Halotolerant species with an accessory genome shared a Kdp potassium transporter and biosynthetic pathways for branched-chain amino acids and the carotenoid lycopene, which are associated with countermeasures against salt stress. Protein-protein interaction network analysis was used to define the genetic determinants of Chryseobacterium salivictor NBC122 that reduce salt damage in bacteria and plants. Sixteen hub genes comprised the aromatic compound degradation and Por secretion systems, which are required to cope with complex stresses associated with saline environments. Horizontal gene transfer and CRISPR-Cas analyses indicated that C. salivictor NBC122 underwent more evolutionary events when interacting with different environments. These findings provide deep insights into genomic adaptation to dynamic interactions between plant-growth-promoting Chryseobacterium and salt stress.

Selection of reference genes and expression of key genes involved in response to short-term soil flooding stress in Prunus persica rootstock ‘Tsukuba 1’

The hypoxic environment directly impacts energy production, growth, and plant development. Under this condition, plants need to rely on anaerobic metabolism to maintain ATP production. These responses are modulated by complex molecular mechanisms that are responsible for gene expression to avoid plant damage. In order to carry out gene expression studies using the real-time PCR technique (RT-qPCR), it is necessary to normalize the data based on optimal reference gene(s) to experimental conditions. Thus, the first aim of this study was to identify likely reference genes and then determine their stability. Besides, we investigated whether adjusting root energy that ‘Tsukuba 1’ plays in the hypoxia is compatible with tolerance or susceptibility to short-term soil flooding. For that, ‘Tsukuba 1’ was submitted to two irrigation treatments: 1) non-flooded, and 2) flooded (1, 2, 4, 8, 16, and 32 h). A comprehensive analysis of performance and stability showed as most stable reference genes, PpTEF2 and PpTUA for roots and PpPLA2 and PpCYP2 for leaves. Conversely, PpTUB and PpEf1α, and PpTUA genes were not suitable reference genes for roots and leaves, respectively. Under short-term soil flooding, ‘Tsukuba 1’ roots generate energy anaerobically firstly through lactic-acid metabolism and then by alcoholic in 2 and 8 h, respectively. In summary, moderate tolerance to short-term soil flooding was observed in peach cultivar ‘Tsukuba 1’, mainly due to stimulation of glycolysis and up-regulation of key gene expression responsible for pivotal pathways involved in energy and ethylene metabolism. However, other physiological and metabolic traits/responses needed to be investigated to confirm this trend.

Are Entomopathogenic Fungal-based Insecticides and Insect Growth Regulator Mixtures Effective Against the Citrus Mealybug, Planococcus citri (Hemiptera: Pseudococcidae), Feeding on Coleus, Solenostemon scutellarioides, Plants under Greenhouse Conditions?

The citrus mealybug, Planococcus citri, is an insect pest of greenhouse-grown horticultural crops. Citrus mealybug causes plant damage when feeding on plant leaves, stems, flowers, and fruits, resulting in a substantial economic loss. Insecticides are applied to manage citrus mealybug populations in greenhouse production systems. Anecdotal information suggests that mixing entomopathogenic fungal-based insecticides with insect growth regulators may be effective for managing citrus mealybug populations under greenhouse conditions. Consequently, we conducted two experiments in a research greenhouse at Kansas State University (Manhattan, KS, USA) in 2023. The experiments were designed to determine the efficacy of three commercially available entomopathogenic fungal-based insecticides [Beauveria bassiana Strain GHA (BotaniGard®), B. bassiana strain PPRI 5339 (Velifer™) and Isaria fumosorosea Apopka Strain 97 (Ancora®)] when mixed with three insect growth regulators [azadirachtin (Azatin® O), novaluron (Pedestal®), and pyriproxyfen (Distance®)] on citrus mealybug feeding on coleus, Solenostemon scutellarioides, plants. The entomopathogenic fungal-based insecticides alone or when mixed with the insect growth regulators were not effective in managing citrus mealybug populations, with <20% mortality during each experiment. In addition, all coleus plants treated with the entomopathogenic fungal-based insecticides had a white, powdery residue on the leaves. Our study demonstrates that entomopathogenic fungal-based insecticides, even when mixed with insect growth regulators, are not effective in managing citrus mealybug populations in greenhouses, which is likely because the environmental conditions (temperature and relative humidity) are not optimal for conidial germination and hyphal infection to occur. Therefore, entomopathogenic fungal-based insecticides have limited use for managing insect pests in greenhouse production systems.

Performance Evaluation of Engine-Operated Weeding Machine

Weeds constitute a serious problem to wheat crops and cause a great loss to the yield. Manual weeding is labor-intensive and time-consuming. Chemical weed control has a negative impact on both the environment and humans. Today the agricultural sector requires non-chemical weed control that safeguards consumers demand for high quality food products and pay special attention to food safety. The objectives of the study was to evaluate the performance of an-engine operated weeder by evaluating the weeding efficiency, plant damage, effective field capacity, field efficiency, fuel consumption, performance index, energy consumption, and cost economics of engine operated weeder in wheat crop. The experimental design was a randomized complete block design and evaluation was conducted at three weeder forward speeds (1.5, 2, and 2.5 km/hr), two depths of operation (from 0 to 20 and from 0 to 40 mm), and three levels of soil moisture content (9.4, 12.34 and 15.25%). The performance of the weeder was found to be optimum at 15.25 percent soil moisture content with 0 to 40 mm depth of operation at a forward speed of 1.5 km/hr. The results revealed that maximum weeding efficiency of 90.1 percent was obtained with lower plant damage of 3.31 percent whereas the effective field capacity, field efficiency, fuel consumption, performance index, and energy consumption were found to be 0.052 ha/hr, 85.99%, 0.41 l/hr, 276.78 ha/hp, and 481.71 MJ/ha, respectively. The analysis revealed that forward speed, depth of operation, and soil moisture had significant effects on weeding efficiency, plant damage, effective field capacity, and fuel consumption at P<0.05 level of significance. The cost of weeding per hectare were 758 and 1920 ETB/ha for engine-operated weeders and traditional weeding methods, respectively. Based on the performance results, it can be concluded that the weeding machine is efficient, effective, and economically viable option with high scope for acceptability among small and medium scale farmers.

The Identification, Diagnosis, Prospective, and Action (IDPA) Method for Facilitating Dialogue between Stakeholders: Application to the Radiological Protection Domain

This article reviews the experience of applying the Identification, Diagnosis, Prospective, and Action (IDPA) facilitating method as a means of promoting practices of dialogue between stakeholders in the radiological protection field. After presenting the characteristics of the IDPA method and its ability to promote active listening, participation, and dialogue among stakeholders facing complex situations, as well as the procedural aspects associated with its practical implementation, the article describes three examples of the application of the method in the field of radiological protection. The first one presents how the IDPA method supported a debate among decision-makers, authorities, experts, professionals, and representatives of non-governmental organizations about how to engage stakeholders in radiological protection. The second example presents how the IDPA method was used in a series of dialogue meetings to explore the challenges of the post-nuclear accident situation resulting from the Fukushima Daiichi Nuclear Power Plant accident. The third one presents the application of the method in the context of a training course organized by Nagasaki University in the affected area close to the damaged plant. Experience has shown that the IDPA method makes it possible to develop responses to problems posed in very different contexts and, in many cases, to find compromises regarding their solutions. The IDPA method has the merit of allowing each of the participants to better understand the situation they are faced with, even if such a positive result is not always achieved.

Intoxication of newly implanted coffee plants by simulated drift of the dicamba herbicide

After the release of soybean cultivars resistant to the herbicide dicamba, this product should be used more frequently in weed management programs, which may increase the risk of drift to neighboring crops, since the molecules are volatile and might cause damage in non-target plants. This work was developed to evaluate the effects of sub-doses of the herbicide dicamba on young coffee plants, simulating a drift situation. The experiment was carried out in a greenhouse, with a randomized block design of eight treatments and five replications. Each plot consisted of a 4 L pot, filled with sieved clayey soil and tanned manure (3:1 v/v), with a seedling of Catuaí IAC 144 coffee. The treatments used were: 0 (control), 0.0001, 0.001, 0.01, 0.1, 1.0, 10.0, and 100.0 g ha−1 of dicamba. Plant's percentual phytotoxicity was evaluated up to 49 days after application (DAA), SPAD index (14, 28, and 42 DAA), and dry matter biomass, at 49 DAA. In all evaluations, no differences were observed regarding phytotoxicity for dicamba sub-doses of up to 0.01 g ha−1. The highest doses of dicamba caused visual injuries of up to 31%. At 49 DAA, there were no differences regarding dry matter biomass. Leaf symptoms caused by the herbicide were observed, such as curling, wrinkling, and epinasty. No plant death was observed. Compared to other crops, coffee might be considered more tolerant to sub-doses of dicamba, with adequate recovery capacity for reduced doses of this herbicide.

Melatonin enhances salt tolerance in sorghum by modulating photosynthetic performance, osmoregulation, antioxidant defense, and ion homeostasis.

Melatonin is a potent antioxidant that can prevent plant damage caused by adverse stresses. It remains unclear whether exogenous melatonin can mitigate the effects of salt stress on seed germination and seedling growth of sorghum (Sorghum bicolor (L.) Moench). The aim of this study was to decipher the protective mechanisms of exogenous melatonin (100 μmol/L) on sorghum seedlings under NaCl-induced salt stress (120 mmol/L). Plant morphological, photosynthetic, and physiological characteristics were analyzed at different timepoints after sowing. Results showed that salt stress inhibited seed germination, seedling growth, and plant biomass accumulation by reducing photosynthetic pigment contents, photosynthetic efficiency, root vigor, and mineral uptake. In contrast, seed priming with melatonin enhanced photosynthetic pigment biosynthesis, photosynthetic efficiency, root vigor, and K+ content under salt stress. Melatonin application additionally enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase) and increased the levels of non-enzymatic antioxidants (reduced glutathione, ascorbic acid) in the leaves. These changes were accompanied by increase in the leaf contents of soluble sugars, soluble proteins, and proline, as well as decrease in hydrogen peroxide accumulation, malondialdehyde content, and electrolyte leakage. Our findings indicate that exogenous melatonin can alleviate salt stress-induced damage in sorghum seedlings through multifaceted mechanisms, such as improving photosynthetic performance and root vigor, facilitating ion homeostasis and osmoregulation, and promoting antioxidant defense and reactive oxygen species scavenging.

Performance Evaluation of an Engine Operated Weeding Machine

Weeds constitute a serious problem to wheat crops and cause a great loss to the yield. Manual weeding is labor-intensive and time-consuming. Chemical weed control has a negative impact on both the environment and humans. Today the agricultural sector requires non-chemical weed control that safeguards consumers’ demand for high-quality food products and pay special attention to food safety. The objectives of the study was to evaluate the performance of engine operated weeding machine by evaluating the weeding efficiency, plant damage, effective field capacity, field efficiency, fuel consumption, performance index, energy consumption, and cost economics of engine operated weeder in wheat crop. The experimental design was a randomized complete block design and evaluation was conducted at three weeder forward speeds (1.5, 2, and 2.5 km/hr), two depths of operation (from 0 to 20 and from 0 to 40 mm), and three levels of soil moisture content (9.4, 12.34 and 15.25%). The performance of the weeder was found to be optimum at 15.25 percent soil moisture content with 0 to 40 mm depth of operation at a forward speed of 1.5 km/hr. The results revealed that maximum weeding efficiency of 90.1 percent was obtained with lower plant damage of 3.31 percent whereas the effective field capacity, field efficiency, fuel consumption, performance index, and energy consumption were found to be 0.052 ha/hr, 85.99%, 0.41 l/hr, 276.78 ha/hp, and 481.71 MJ/ha, respectively. The analysis revealed that forward speed, depth of operation, and soil moisture had significant effects on weeding efficiency, plant damage, effective field capacity, and fuel consumption at P<0.05 level of significance. The cost of weeding per hectare was 758 ETB/ha and 1920 ETB/ha for engine-operated weeders and traditional weeding methods, respectively. Based on the performance results, it can be concluded that the weeding machine is an efficient, effective, and economically viable option with high scope for acceptability among small and medium-scale farmers.

The application of plant growth-promoting rhizobacteria enhances the tolerance of tobacco seedling to salt stress

The application of plant growth-promoting rhizobacteria (PGPR) is a novel and an efficient strategy for improving soil degradation and productivity. However, the effect of PGPR on tobacco (Nicotiana tabacum L.) seedling growth under salt stress remains unclear. Here, microcosm experiments were designed to verify the effects of Bacillus cereus TC012 (BC), Bacillus methylotrophicus TC023 (BM), and Bacillus amyloliquefacien TC037 (BA) on tobacco grown in salt-affected soil. The results showed that BC, BM, and BA treatments significantly increased the height of tobacco plants by 38.65%, 91.94%, and 90.66%, respectively. Furthermore, the growth of various components of tobacco plant, such as stem girth, seedling biomass, carotenoid, and chlorophyll were stimulated in salt-affected soils. The changes in the salinity of the tobacco plant mostly relies on the improvement of proline, soluble protein, soluble sugar content, plant protective enzymatic activity, and K+/Na+ ratios. Increases in indole-3-acetic acid, zeatin riboside and gibberellic acid also promoted tobacco growth. Additionally, inoculation with PGPR enhanced the enzymatic activity of laccase, urease, neutral protease, acid phosphatase, and sucrase in soil samples and had positive effects on the physicochemical properties. The soil bacterial communities significantly improved after inoculation with PGPR. In particular, the relative abundance of Pseudomonas and Bacillus significantly increased. Overall, PGPR inoculation has great potential to alleviate salt damage in tobacco plants and may have far reaching benefits to the agricultural community.

Bio-efficacy of newer insecticides and bio-pesticides against termite on chickpea in arid region of Rajasthan

The seed treatment, as well as soil application of imidacloprid 600 FS @ 5 ml/kg + Beauveria bassiana 1.15 WP @ 2 kg /ha, was found most effective against termite (9.34% plant damage) after 110 days of crop sowing, followed by fipronil 5 SC @ 5 ml/ kg + Metarrihizium anisopliae 1.15 WP @ 2 kg/ha (10%) and clothianidin 50 WDG @ 2 g/ kg + Beauveria bassiana 1.15 WP @ 2 kg /ha (10.62%). The treatments alone seed treatment of imidacloprid 600 FS @ 5 ml/ kg seed (11.56%) followed by fipronil 5 SC @ 5 ml/ kg seed (12.03%) and clothianidin 50 WDG @ 2 g/ kg seed (12.65%) were found moderately effective while, bio-pesticides viz., Metarrihizium anisopliae 1.15 WP @ 2 kg/ha and Beauveria bassiana 1.15 WP @ 2 kg /ha with 15.78 and 15.47 per cent plant damage were found least effective for controlling the termite population. The maximum yield was obtained in imidacloprid 600 FS + Beauveria bassiana 1.15 WP (18.70 q ha-1) followed by fipronil 5 SC + Metarrihizium anisopliae 1.15 WP (18.20 q ha-1) and clothianidin 50 WDG + Beauveria bassiana1.15 WP (18.00 q ha-1), respectively.

Recruitment of Hippodamia variegata by active volatiles from Glycyrrhiza uralensis and Alhagi sparsifolia plants infested with Aphis atrata.

Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), a dominant predatory natural enemy species in cotton-planting, is a key biological control agent for aphids in China. Our previous study showed that herbivore-induced plant volatiles (HIPVs) from Glycyrrhiza uralensis (Fisch.) (Fabales: Fabaceae) and Alhagi sparsifolia (Desv.) (Fabales: Fabaceae) plants infested with Aphis atrata (Zhang) (Homoptera: Aphididae), were important semiochemicals for Hippodamia variegata to locate aphids. However, little was known about the varieties and function of active volatiles from HIPVs of the two plant species. In this study, results from gas chromatography-electroantennography detection (GC-EAD) demonstrated that seven HIPVs (butyl acrylate, α-pinene, butyl isobutyrate, β-pinene, butyl butyrate, 1,3-diethylbenzene and 1,4-diethylbenzene) identified from the two damaged plant species elicited antennal responses from Hippodamia variegata. Also, results from gas chromatograph-mass spectrometry (GC-MS) analysis showed that the concentrations of the seven active volatiles were significantly higher than those from corresponding healthy plants. Hippodamia variegata exhibited varying degrees of response to each active volatile in electroantennography (EAG) trials, however, only α-pinene, butyl isobutyrate, β-pinene and butyl butyrate significantly attracted Hippodamia variegata in behavioral trials conducted in the laboratory. They also had a better trapping effect on Hippodamia variegata in cotton fields. Four active compounds (α-pinene, butyl isobutyrate, β-pinene and butyl butyrate) identified from two damaged plant species were considered the most effective HIPVs that attract Hippodamia variegata. These findings provide possibilities for the development of Hippodamia variegata attractants. They also provide a theoretical basis for the biological prevention and control of aphids using Hippodamia variegata. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessment of tractor track width compatibility with crop inter-row spacing

Various factors can exert detrimental effects on crop growth and development, among which the influence of the machinery's running gear within the machine-tractor unit stands out, particularly within the soil vicinity encompassing the plant's root system. As a result, the area of soil compaction arising from tractor wheel pressure increasingly covers the plant's protective zone. This poses challenges for both root system growth and development, as well as the optimal uptake of soil nutrients, often leads to plant damage or even trampling. Presently, there is no universally accepted metric for assessing the compatibility between tractor track width and the specific inter-row spacing under cultivation. (Research purpose) Development of an indicator to assess the compatibility of the tractor track width with the cultivated inter-row spacing. (Materials and methods) The analysis demonstrates that the level of compatibility of the tractor track to the crop inter-row spacing is determined based on the dimensions of the crop spacing, the tractor track width, the protective zone outlined by agrotechnical standards, the deviation of the wheel trajectory from the axis of row symmetry, and tire size. (Results and discussion) An analytical correlation has been derived to determine the level of compatibility between tractor track width and crop inter-row spacing, using the context of cotton cultivation as an illustrative example. It has been revealed that among the serial tractors utilized within cotton farms across the region, full-fledged operational performance is exclusively achieved when row spacings measure 60 and 90 centimeters. In contrast, the utilization of this machinery on row spacings of 70 and 76 centimeters leads to detrimental outcomes such as row trampling and plant damage. (Conclusions) The viability of the developed indicator has been determined and validated. The improvement of the tractor propulsion system should be aimed at devising a technical solution that facilitates seamless adjustment of track width over a broad spectrum, thus allowing for adaptability to diverse row spacing requirements.

Exogenous Salicylic Acid Alleviates NO2 Damage by Maintaining Cell Stability and Physiological Metabolism in Bougainvillea × buttiana 'Miss Manila' Seedlings.

Exogenous substances can alleviate plant damage under adverse conditions. In order to explore whether different concentrations of salicylic acid (SA) can play a role in the resistance of Bougainvillea × buttiana 'Miss Manila' to nitrogen dioxide (NO2) stress and the relevant mechanisms of their effects, different concentrations of SA were applied locally under the control experiment condition of 4.0 μL·L-1 NO2, and the role of SA in alleviating injury was studied. The findings noted a significant increase in metabolic adaptations and antioxidant enzyme activities following 0.25-0.75 mM SA application (p < 0.05), except 1 mM. Superoxide dismutase (SOD) and catalase (CAT) in particular increased by 21.88% and 59.71%, respectively. Such an increase led to effective control of the reduction in photosynthetic pigments and the photosynthetic rate and protection of the structural stability of chloroplasts and other organelles. In addition, the activity of nitrate reductase (NR) increased by 83.85%, and the content of nitrate nitrogen (NO3--N) decreased by 29.23% in nitrogen metabolism. Concurrently, a principal component analysis (PCA) and a membership function analysis further indicated that 0.75 mM SA provided the most notable improvement in NO2 resistance among the different gradients. These findings suggest that 0.25-0.75 mM SA can relieve the stress at 4 μL·L-1 NO2 injury by effectively improving the antioxidant enzyme activity and nitrogen metabolizing enzyme activity, protecting the photosynthetic system and cell structure, but 1 mM SA had the opposite effect. In the future, the specific reasons for inhibition of SA at high concentrations and the comprehensive effects of the application of other exogenous compounds should be further studied.

Soil acidification and salinity: the importance of biochar application to agricultural soils.

Soil acidity is a serious problem in agricultural lands as it directly affects the soil, crop production, and human health. Soil acidification in agricultural lands occurs due to the release of protons (H+) from the transforming reactions of various carbon, nitrogen, and sulfur-containing compounds. The use of biochar (BC) has emerged as an excellent tool to manage soil acidity owing to its alkaline nature and its appreciable ability to improve the soil's physical, chemical, and biological properties. The application of BC to acidic soils improves soil pH, soil organic matter (SOM), cation exchange capacity (CEC), nutrient uptake, microbial activity and diversity, and enzyme activities which mitigate the adverse impacts of acidity on plants. Further, BC application also reduce the concentration of H+ and Al3+ ions and other toxic metals which mitigate the soil acidity and supports plant growth. Similarly, soil salinity (SS) is also a serious concern across the globe and it has a direct impact on global production and food security. Due to its appreciable liming potential BC is also an important amendment to mitigate the adverse impacts of SS. The addition of BC to saline soils improves nutrient homeostasis, nutrient uptake, SOM, CEC, soil microbial activity, enzymatic activity, and water uptake and reduces the accumulation of toxic ions sodium (Na+ and chloride (Cl-). All these BC-mediated changes support plant growth by improving antioxidant activity, photosynthesis efficiency, stomata working, and decrease oxidative damage in plants. Thus, in the present review, we discussed the various mechanisms through which BC improves the soil properties and microbial and enzymatic activities to counter acidity and salinity problems. The present review will increase the existing knowledge about the role of BC to mitigate soil acidity and salinity problems. This will also provide new suggestions to readers on how this knowledge can be used to ameliorate acidic and saline soils.

Biochemical and physiological mechanisms allowing olive trees to survive and produce under water stress conditions

The beneficial properties of olive (Olea europaea L.) edible fruits and their oil play an important part in our diet. Severe summer conditions, including low rainfall, excessive heat load and high daily irradiance, characterize arid and semiarid regions where olive is produced. Although it is highly aggravated by other stresses, water stress is usually the most critical during summer-time. Under severe water stress conditions, a cultivar of any olive tree needs specific biochemical and physiological mechanisms in order to survive and be productive. It is well-known that these water stress resistance mechanisms generally act simultaneously. Nevertheless, water stress adaptability not only integrates the water stress resistance concept (i.e., escape, avoidance and/or tolerance to water stress) but also the recovery capacity. All of them play a major role in plants’ growth and survival, especially when plants are continuously exposed to repeated events of water stress and adequate water levels during their lifetime. Water stress, heat and high irradiance, especially in association with each other, also damage plant functions. As a result, different resistance mechanisms are adopted by plants. This review summarizes each of these mechanisms.