Plant Protection
This study aims to exploit volatile components of endophytic fungus HDM07 isolated from Cannabis sativa L., and to explore the biosynthetic pathway of secondary metabolites from HDM07. The research took the endophytic fungus HDM07 obtained from Cannabis sativa L. as the subject. GC-MS and retrieval mass spectrometry database were employed to identify the volatile components in both the fermentation broth and mycelium of HDM07. Morphological observation and 18S rDNA sequence analysis were conducted for strain identification. Results indicated that the method of GC-MS and mass spectrometry analysis, along with database retrieval from endophytic fungi HDM07, determined 11 volatile components in the fermented liquid. Furthermore, fungus HDM07 revealed 14 volatile constituents in mycelium and Cannabis sativa L. leaf identified 12 elements. In a blank reference substance solution (PDB medium), appraisal revealed 7 ingredients. The endophytic fungus HDM07 was identified as Alternaria alternate. These findings suggest that the synthesis pathways of volatile components in HDM07 fermentation broth and mycelia are both related yet distinct. Both the fermentation broth and mycelium of endophytic fungus HDM07 contained similar or identical volatile components to those found in Cannabis sativa L., and also contained unique ones, indicating a certain correlation between the strain and its host plant's synthesis of volatile components.
To deepen the understanding of the interaction between plants and entophytic fungi, and better use the entophytic fungi in the future, the diversity, biological functions, ecological functions and resource utilization of endophytic fungi in plants were reviewed. Endophytic fungi are a kind of symbiotic fungal groups in plants, and they live and interact with plants in roots, stems, leaves and other parts of plants. They can promote plant growth and development through various ways, including providing nutrients needed by plants, enhancing plant disease resistance and improving plant adaptability to adversity. This paper laid a foundation for the effective use of entophytic fungi in the future, and provided a better theoretical basis and practical guidance for plant ecology and agricultural production.
To screen the biocontrol bacteria of Salvia miltiorrhiza root rot, the infected S. miltiorrhiza and rhizosphere soil from healthy S. miltiorrhiza in Rizhao, Linyi, and Tai'an cities of Shandong Province were used as test materials. The tissue separation method was used to isolate the root rot pathogen from infected S. miltiorrhiza. The gradient dilution plate method and disk diffusion method were used to screen biocontrol bacteria from rhizosphere soil. Identification was achieved through the use of morphological characteristics and 16S rRNA, and control effect testing was carried out on the detached S. miltiorrhiza. The results showed that the pathogen RBT-2-1 isolated from infected S. miltiorrhiza was Fusarium equiseti, and the biocontrol bacterium i screened from rhizosphere soil was Pseudomonas chloriraphis subsp. aurantiaca. The antibacterial rate of i against TBG-2-1 was 66.67%. The control effect of i against TBG-2-1 on the detached S. miltiorrhiza in the prevention group was higher than in the treatment group. Furthermore, the addition of i in the prevention group resulted in the best control effect, reaching 44.45%. The prevention group of adding i was 1.6 times higher than the prevention group without addition, and 7.0 times higher than the treatment group. It can be concluded that the sequence and frequency of inoculation with i will affect the prevention efficacy of TBG-2-1. This study serves as a guide for future field experiments.
The control effects of Streptomyces costaricanus strain A-m1 on wheat scab were studied in order to lay a foundation for the development of biocontrol agents for wheat production. The effects of A-m1 on spore germination and mycelial growth of wheat scab pathogen were determined, the genetic and enzymatic basis of the bacteriostatic effect of strain A-m1 was analyzed, and the control effect of spraying A-m1 bacterial liquid at flowering stage and applying A-m1 solid bacterial fertilizer at sowing stage on wheat scab was explored. The findings revealed that strain A-m1 exerted a potent inhibitory influence on both the conidial germination and mycelial expansion of Fusarium graminearum. The genomic of A-m1 encoded genes for the synthesis of streptomycin and tetracycline antibiotics, as well as genes such as casein, β-1, 3-glucanase, cellulase, and chitinase. They had the effect of inhibiting or decomposing pathogenic bacteria, and further biochemical analysis verified the secretion of the four enzymes. Spraying A-m1 fermentation broth at wheat flowering stage had a control effect of 52.28 % on wheat scab, a level of efficacy comparable to that of a 1000-fold dilution of 80% carbendazim solution. The application of A-m1 bacterial fertilizer substituting a portion of the traditional compound fertilizer at the sowing stage, led to a marked increase in the activity of defense enzymes, including polyphenol oxidase, peroxidase, catalase, and phenylalanine ammonia-lyase. At the same time, the content of malondialdehyde was lower, and the control effect on wheat scab was 57.18 %. In this study, the control effect of strain A-m1 on wheat scab was clarified, and the underlying mechanisms of its protective action had been partially dissected. Field experiments also confirmed the control effect of A-m1 fermentation broth spraying and strain A-m1 bacterial fertilizer application on wheat scab during sowing period, which laid a good foundation for the reduction of chemical fertilizers and pesticides in wheat production.
This study aims to clarify the effect of pesticide synergists (mainly composed of compound modified vegetable oil, complex sugar alcohols, and non-ionic surfactant) on the physical properties of s-metolachlor, metolachlor, acetochlor, fomesafen, bentazone, clomazone, quizalofop-p-ethyl, atrazine, mesotrione, tembotrione, topramezone and diquat. The effects of pesticide synergists on a series of physical indexes of 12 herbicides were measured. The results showed that the physical properties of 12 herbicides were improved by different pesticide synergists. After each herbicide is mixed with pesticide synergist, 11 herbicides had a significant decrease in contact angle, 9 herbicides had a significant increase in expansion diameter, 3 herbicides had a significant decrease in surface tension, 7 herbicides had a significant increase in maximum retention on broadleaf weeds [Humulus scandens (Lour.) Merr.], and 9 herbicides had a significant decrease in penetration time. The results show that pesticide synergists have a basic condition for enhancing the physical properties of the 12 herbicides, and the synergistic effect of their weeding effect needs to be further verified through bioassay.
In order to strengthen China's ecological security barrier and protect biodiversity, and to prevent the ecological threats posed by the large-scale invasion and spread of Aegilops tauschii Coss., it is necessary to implement comprehensive control measures and dynamically monitor its invasion and spread trends. Based on the issues of prevention and management of A. tauschii in China, this study took A. tauschii as the research subject and utilized the Maximum Entropy (MaxEnt) model to analyze its potential suitable habitat range in China. Furthermore, the study employed Principal Component Analysis (PCA) to examine the climatic ecological niche changes of A. tauschii during its invasion process into China. By using ecological niche modeling, this study analyzed the current status and potential distribution of A. tauschii, identified the regions in China with the highest risk of invasion by this species, such as central China, southern Fujian, Zhanjiang in Guangdong, Hainan, the southwest and Tacheng regions of Xinjiang, and the western and southeastern parts of Tibet. The main ecological factors influencing its distribution are the precipitation of the driest month (Bio14) and the mean temperature of the warmest quarter (Bio10). High ecological niche stability indicates that A. tauschii is in an ecologically conservative state during the invasion process. The difference between the climatic ecological niche of A. tauschii in China and its native ecological niche is due to the unfilled niche, where the climatic ecological niche of the invasive population is merely a subset of the native ecological niche.
To investigate the inhibitory effect of soil amendment (SA) in combination with entomopathogenic nematode (Heterorhabditis beicherriana) on Meloidogyne incognita, and its impact on the ecological environment of cucumber rhizosphere soil, we used the cucumber cultivar ‘Qianqiu No.1’ as the test variety, and set up six different experimental groups to study the community structure of soil nematode, ecological diversity and functional diversity of cucumber rhizosphere soil. The results showed that after 60 days of experiment, the SA and nematode H. beicherriana group contained fewer parasitic nematodes in root nodules, and more Rhabditis and Mesorhabditis nematodes. The trophic diversity and basal index were increased, and the nematode channel ratio was significantly increased, and the soil organic decomposition was mainly bacterial decomposition. The nematode population remained predominantly in area A, characterized by better soil nutrients and bacterial decomposition, whereas in other groups, there was a gradual decrease from area A to area D. The results showed that the SA soil restorer combined with entomopathogenic nematode (H. beicherriana) could effectively inhibit M. incongnita, and at the same time improve the diversity of soil nematodes, effectively alleviate the degradation trend of soil food web.
The study aims to screen the safe and efficient fungicide for controlling citrus melanose, clarify the control effect and the appropriate dosage of the new compound isopyrazam·tebuconazole 40% SC on citrus melanose. Field efficacy tests of the new compound isopyrazam·tebuconazole 40% SC for controlling citrus melanose were carried out for two consecutive years from 2021 to 2022. The results of the two years experiments showed that isopyrazam·tebuconazole 40% SC 200 mg/kg had a good control effect on citrus melanose. After three times of application in 2021, the control effect of isopyrazam·tebuconazole 40% SC 200 mg/kg on citrus leaves citrus melanose and fruits citrus melanose were 79.60% and 77.97%, respectively. After three times of application in 2022, the control effect of isopyrazam·tebuconazole 40% SC 200 mg/kg on citrus leaves citrus melanose and fruits citrus melanose were 81.65% and 76.37%, respectively, which were significantly better than 20% isopyrazam wettable powder and 430 g/L tebuconazole suspension. The isopyrazam·tebuconazole 40% SC is safe and efficient for the prevention and treatment of citrus, which is worthy of application in the demonstration and promotion of citrus melanose control.
In order to compare the differences of resistance to rice blast disease in Yunnan among japonica rice cultivars collected from 17 provinces, and to screen favorable resistant resources of rice, we employed the method of natural induction in field blast nursery to assess the resistance of 1050 japonica rice cultivars against leaf and panicle blast. The results indicated that among the 1050 japonica rice cultivars, there was lighter incidence of leaf blast and more severe incidence of panicle blast. Regarding leaf blast resistance, the cultivars exhibiting high resistance, resistance, moderate resistance, moderate susceptibility, susceptibility, and high susceptibility accounted for 28.48%, 10.95%, 9.14%, 19.24%, 20.00%, and 12.19%, respectively. As for panicle blast resistance, the cultivars exhibiting high resistance, resistance, moderate resistance, moderate susceptibility, susceptibility, and high susceptibility accounted for 3.71%, 0.38%, 2.57%, 19.62%, 22.57%, and 51.14%, respectively. Further analysis of the leaf and panicle blast results revealed that 69 japonica rice cultivars had resistance to both leaf and panicle blast. These 69 cultivars were collected from five provinces of Jilin, Heilongjiang, Liaoning, Yunnan, and Jiangsu. These results suggested that these cultivars with good resistance against both leaf and panicle blast in blast nursery could be served as important resistance resources for blast disease-resistant rice breeding, and discovery of new genes conferring resistance to rice blast.
To determine the relationship between population density of Meloidogyne graminicola and yield loss in upland rice, the effects of Meloidogyne graminicola initial population density (Pi) on the yield of upland rice and reproduction of nematodes were evaluated in pot experiments under the screen house condition with dry planting and management. The results revealed a linear regression relationship where rice parameters such as root length, root weight, plant height, tiller number, panicle length, 1000-seed weight and single basin grain weight decreased as Pi increased. The yield loss ranged from 28.4% at a Pi of 2 eggs and J2/100 cm3 soil to 67.8% at a Pi of 200 eggs and J2/100 cm3 soil. The reproduction factor of nematodes followed a declining trend with Pi. The relationship between population density and relative yield followed the Seinhorst model, Y=0.24+0.76(0.3252)(Pi). A significant positive correlation was noted between upland rice yield loss and Pi of 2 to 200 eggs and J2/100 cm3 soil under dry planting and management, indicating a high risk of harm to upland rice caused by M. graminicola.
In order to clarify the effects of feeding density on the development period, pupa rate, adult rate and weight of Hippodamia variegata, as well as to explore efficient feeding techniques for this species, four groups of early-stage larvae were subjected to different feeding densities (A: 100 heads/box, B: 200 heads/box, C: 300 heads/box, D: 400 heads/box, the volume of the breeding box is 1000 mL). The molting, pupa, eclosion time and the number of pupation and eclosion adults of each age of H. variegata were observed and counted. The results showed that the development duration of larvae and pupa of H. variegata in groups A, B, C, and D were (11.75±0.65) days, (12.06±0.77) days, (12.45±0.60) days, and (12.70±0.21) days, respectively. The number of pupation was (85.25±4.87), (147.50±3.12), (193.75±21.40) and (156.25±29.62), of which (49.00±6.68), (74.25±12.06), (107.75±16.76) and (103.75±15.78) pupae could be collected. The number of eclosion adults was (75.25±6.73) heads, (123.75±8.05) heads, (160.25±27.22) heads and (110.75±26.68) heads, respectively. The weight of adults was (7.39±0.13) mg/head, (7.32±0.29) mg/head, (7.29±0.20) mg/head and (6.56±0.12) mg/head, respectively, and the number of abnormal adults was (5.25±1.65) heads, (12.75±4.33) heads, (19.50±5.24) heads, (10.50±3.90) heads, respectively. With the increase of feeding density, the development period of H. variegata was gradually prolonged, the number of pupation, eclosion and deformity was gradually increased, and the pupation rate, eclosion rate and adult weight gradually decreased. In conclusion, the instar larvae of H. variegata had a feeding density of 300 heads/box, and the number of pupation and eclosion adults was large, and the weight was normal, which was the optimal feeding density.
To explore the effects of exogenous selenium (Se) on rice growth and survival of Sogatella furcifera feeding on Se-treated rice plants, a susceptible cultivar 'Taichung Native 1' (TN1) was served as the test rice variety. Six Se concentrations of 10, 20, 30, 40, 50 and 60 μmol/L were set up by adding sodium selenite (Na2SeO3) to the nutrient solution, and 0 μmol/L was used as the control to determine the effects of different concentrations of Se on rice growth and the survival of S. furcifera feeding on Se-treated rice plants. The results indicated that the plant height, root length, fresh weight and dry weight per plant treated with 10 μmol/L Se were significantly higher than that of control; while the plant height, root length, fresh weight and dry weight per plant treated with 20-60 μmol/L Se were lower than that of control. Se content in rice plants were increased significantly with the increase of Se concentration in nutrient solution, while survival rate of S. furcifera were decreased significantly with the increase of Se content in rice plants. The survival rate of S. furcifera fedding on rice plants treated with 10 μmol/L Se decreased significantly on the 4th to 7th day after the treatment. In conclusion, 10 μmol/L is the appropriate concentration of Se, which can promote rice growth and reduce the survival rate of S. furcifera.
In order to effectively control wheat yellow mosaic disease at seedling stage and reduce the effect on wheat yield, the occurrence of wheat yellow mosaic disease was investigated in the field from 2018, and the regularity of occurrence of wheat yellow mosaic disease was analyzed systematically. From 2022 to 2023 year, three plots were selected to conduct pesticide control experiments at seedling stage, two sprays of 20% moroxydine hydrochloride WP 2250 g + 30% difluorophos WP 750 g + 0.01% brassinolide soluble solution 225 mL + 6% oligosaccharide·Chain protein WP 1200 g + 98% Monopotassium phosphate 2250 g + 750 g water soluble fertilizer containing amino acids were applied to wheat at rising stage, the area was 1333.4, 666.7, 666.7 m2 respectively, and the control was sprayed with water, the area was 1333.4, 666.7, 666.7 m2respectively. The results showed that spraying fungicide could reduce the severity of wheat yellow mosaic disease, and the average control effect was 29.6% and 42.46%, respectively, and the average plant height and fresh weight increased by 3.24 cm and 0.44 g, respectively, the average number of secondary roots per plant increased by 3.17. The yields of the three plots were 5657.85, 6777.12, 7868.37 kg/hm2, respectively, and those of the control were 4776.52, 5435.58, 7223.63 kg/hm2, respectively. The yields of the three plots were increased by 881.32, 1341.54, and 644.75 kg/hm2, respectively, the average yield increase was 955.87 kg and 17.35%. Spraying fungicide at the seedling stage of wheat can reduce the damage degree of the disease and achieve the effect of preventing disease, reducing damage and increasing yield of wheat.
In order to understand how the herbivores-induced plant volatiles attract natural enemies for pest defense, the recent research status, influencing factors and progress of research on herbivores-induced plant volatiles around the world were reviewed. The release and action effect of plant volatiles are influenced by multiple factors, and their action pathways are closely related to the chemoreceptor genes of insects. In recent years, studies on the action mechanisms of plant volatiles attracting natural enemies have been carried out extensively at home and abroad, and most of them focus on the identification of volatile compounds, behavioral selection experiments and the identification and functional analysis of chemoreceptor genes associated with natural enemies. By analyzing and summarizing the studies, the future development directions on the biological control of pests by natural enemies lured by plant volatiles and related genes were discussed, aiming to provide theoretical support for future development of green plant protection and sustainable agriculture.
The purpose of this study is to explore the composition and diversity of arthropod communities in ecosystems, which is crucial for understanding the ecological functions of arthropod communities. Tobacco fields, as one of the important types of farmlands, have a certain level of complexity and uniqueness in their ecosystems. The study of arthropod community ecology in tobacco fields is of great significance for the sustainable development of agricultural ecosystems. Firstly, the current status of arthropod community composition in tobacco fields is reported, including the composition, dynamics, diversity, and measurement methods of dominant pests and natural enemies in different tobacco-growing regions in China. Secondly, the factors influencing arthropod community diversity in tobacco fields are summarized, such as agricultural cultivation practices, chemical pesticide use, organic agriculture, and biological control, which have direct or indirect impacts on species diversity and abundance of arthropod communities in tobacco fields. Finally, the issues and challenges in current research are analyzed, and prospects for future research directions and trends are discussed. Through a comprehensive analysis and summary of arthropod community ecology in tobacco fields, the scientific basis and guidance are provided for the conservation and management of tobacco field ecosystems.
The aim of the experiment was to investigate the insecticidal activity of ethanol extract of Rumex acetosa L. against three common pests (Callosobruchus chinensis, Sitophilus oryzae, Plutella xylostella), in order to provide a theoretical basis for the subsequent study of the mechanism of R. acetosa insecticidal. The crude extract of R. acetosa with different concentrations was used as the test liquid, and the three pests were tested by repellent and antifeedant methods, respectively. The results showed that the best repellent concentrations of R. acetosa crude extract against C. chinensis and S. oryzae were 30 mg/mL and 50 mg/mL, respectively. For the 2nd instars of P. xylostella, the concentration of 30 mg/mL to 80 mg/mL had a remarkable anti-feeding effect, and the anti-feeding rate could reach more than 84%. Therefore, the crude extract of R. acetosa is expected to be an effective pest repellent and antifeedant, which is worthy of further study.
In order to explore the effect of pine needle extracts on tea plant growth and pest control, tea trees treated with and without pine needle extracts were used as experiment materials, and the combined transcriptome and metabolome analysis was conducted to analyze the internal mechanism. The results showed that pine needle extracts could promote the growth of tea plants, with the increasing germination density, the relative content of chlorophyll in tea plant leaves, and the yield of tea without reducing the quality of tea. In this process, the expression of AP2/ERF transcription factors was suppressed, and ethylene signaling pathway played an important role of negative regulator. Besides, pine needle extracts treatments did not affect the community structure of arthropods of tea plants, and displayed a certain control effect on mites and tea green leafhoppers. The combined analysis of transcriptome and metabolome showed that the improvement of insect resistance of tea plant might be due to the activation of polyphenol and phospholipid metabolic pathways of tea plants, and the contents of corresponding metabolites were significantly increased. Thus, the antioxidant and free radical scavenging ability of tea plants were improved, so as to enhance the stress resistance of tea plants. In general, the results can provide a basis for the development and utilization of natural plant stress inducers.
This paper reviews the cases of peach aphid (Myzus persicae) resistance to various insecticides reported in the literature in recent years, analyses the possible mechanisms of peach aphid resistance, and evaluates the main patterns of resistance development in peach aphid, including interactive resistance, and predicts the development trend of resistance based on these patterns. Practical solutions to the growing problem of peach aphid resistance are summarized, including the alternation of insecticides with different mechanisms of action, the introduction of biological control methods, and the strengthening of resistance monitoring and so on, which are intended to provide new ideas for the management of agroforestry pests to meet the challenges posed by peach aphid resistance, thereby improving productivity and promoting the sustainable development of the natural environment. At the end of the article, several active areas of insect resistance research are outlined.
In order to clarify the pathogen causing guava fruit spot disease and to control the disease, the pathogens from guava leaves and fruit with typical symptoms were collected for isolation and purification. Based on tissue isolation method, phylogenetic analysis, morphological characters and Koch’s postulates, the pathogen was identified as Pestalotiopsis microspora. Inhibitory activities of six fungicides to P. microspora Guava A, Guava B and Guava C were determined using mycelial growth method. The result indicated 450 g/L prochloraz EW had the best inhibitory effect on the mycelial growth, with an EC50 values of 0.0019 μg/mL; the following was 60% pyraclostrobin·fluxapyroxad SC, 75% trifloxystrobin·tebuconazole WG and 325 g/L difenoconazole·azoxystrobin SC, with EC50 values of 0.1479 μg/mL, 0.1697 μg/mL and 0.1739 μg/mL. The result provides a reference for the control of fruit spot disease on guava in field.
This study aims to screen one or two kinds of herbicides which are suitable for the control of X. sibiricum in Ningxia region. The plant control effects and fresh weight control effects of 5 herbicides, including 2 methyl 4 chlorodimethylamine salt, fluroxypyr, saflufenacil·glyphosate, nitrosulone, topramezone on X. sibiricum, were determined by field experiments. After 21 days, the results of plant control effects showed that among the five herbicides, 2 methyl 4 chlorodimethylamine salt 60% AS with 750 mL/hm2, fluroxypyr 200 g/L EC with 900 mL/hm2, and saflufenacil·glyphosate 40% OD with 1500 mL/hm2 presented excellent plant control effect, and the control effects were 96.62%, 98.31%, and 100%, respectively; the results of fresh weight control effects showed that fluroxypyr 200 g/L EC with 900 mL/hm2 and saflufenacil·glyphosate 40% OD with 1500 mL/hm2 had remarkable control effects, which were 93.94% and 100%, respectively. Based on the results of control effects, as well as the different crops, the biocidal herbicide saflufenacil·glyphosate can be selected for the control of X. sibiricum in wasteland, forest land, ditches, etc. In the control of X. sibiricum in gramineous crop fields such as wheat and corn, fluroxypyr herbicides were the first choice.
Plant Protection
