Plant Sap Research Articles

Hyalopterus pruni (Geoffroy)'nin morfolojik ve moleküler teşhisi üzerine araştırma

Aphids are one of the most important groups of insects that cause damage to agricultural crops, ornamental plants, as well as herbaceous and woody plants in their natural habitats. Aphids that feed on plant sap can cause significant crop losses worldwide, ranging from 70% to 80%, due to stunted growth, deformation, wilting, and other detrimental effects on plants. Despite the chemical, biological, and integrated pest management methods applied against these damages, aphids have rapidly expanded their distribution areas and their damages have been increasing in recent times. Hyalopterus Koch (Hemiptera: Aphididae), a genus of aphids, are known worldwide as pests that infest Prunus trees, which are stone fruit trees. They cause damage by feeding on the trees and also by transmitting plant viruses. Subsequently, improper and indiscriminate use of chemical control methods negatively impacts both human and environmental health. Accurate identification of aphids, especially in terms of invasive species, is crucial for early detection of their damages in the initial stages. The mitochondrial cytochrome c oxidase subunit I (COI) gene is an effective gene region used in the identification of many economically important plant pests worldwide. In this study, a total of 50 individuals of Hyalopterus pruni (Geoffroy) were collected from three localities Şarköy (Ulaman, Bulgurlu, Gölcük, Cumhuriyet, Mürefte, Hoşköy, Gaziköy, Tepeköy, Palamut), Süleymanpaşa (Yüzüncüyıl, Altınova, Banarlı, Barboros, Bıyıkali, Çınarlı, Değirmenaltı, Ferhadanlı, Hürriyet, Karacakılavuz, Karaevli, Naip, Namık Kemal and Marmaraereğlisi (Bahçelievler, Cedit Ali Paşa, Dereağzı, Mustafa Kemal Paşa, Sultanköy, Türkmenli, Yakuplu and Yeniçiftlik) in Tekirdağ province. The species H11, H41, and H61, which were selected to represent three counties, were sequenced, and the molecular sequence results revealed that H. pruni, as morphologically described, showed 99% consistency at the molecular level.

Cicada feast and food links: Grey-headed flying fox preys on black prince in south-East Australia

Cicada mass emergence offers a plentiful and energy-rich food source for a variety of predators, mainly birds and spiders. Megabats (Pteropodidae) mostly feed on nectar and fruits, but occasionally prey on insects such as sap-sucking cicadas and fruit-eating beetles. We observed and documented with photographs the behavioural repertoire of the Grey-headed Flying Fox Pteropus poliocephalus while hunting and consuming the Black Prince cicada Psaltoda plaga in Sydney, New South Wales, Australia. The bats used three main tactics while hunting the cicadas: a) flushing and/or catching cicadas on tree foliage while clambering over branches or landing on the foliage, b) lunging from a perch after spotting a resting cicada, and c) pursuing cicadas on the wing. Upon securing a cicada the bats flew off and landed on a feeding perch, where they chewed the prey and spat the remains as a pellet below this perch. On the ground, the pellets were usually sought by large ants that tore off pieces from these remains, the ants transporting them to the nest. Small ants aggregated on the pellets probably to seek the remaining sap, after which they left the pellets. The above described events showed three main food links: a) cicadas feeding on plant sap, b) bats preying on cicadas and spitting the remains as pellets, and c) ants feeding on bat pellets. The links illustrate a food chain that include plants, cicadas, bats, and ants. Additional food links we observed were: 1) cicadas feeding on different plants, 2) cicadas preyed on by diurnal animals, 3) dead cicadas consumed by ants, 4) dead bats consumed by birds, and 5) nocturnal raptorial bird that may prey on bats. This report seems the first to mention food links within a megabat-insect trophic interaction.

Impact of Cymbidium mosaic virus on Native and Cultivated Orchids in Western Ghat - Kerala.

Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) are two major orchid viruses detected in native and imported orchid plants of India. These viruses are growth debilitating with high stability and high spread rates. A survey was conducted in eight districts of Kerala for detecting the prevalence of CymMV and ORSV in native and cultivated orchid plants. DAC- ELISA technique using specific antibodies for CymMV and ORSV was used to detect viruses in collected orchid samples. The presence of CymMV was detected in all orchid nurseries surveyed, and the incidence varied from five to 100% in different areas. The coat protein of the CymMV strain was cloned and sequenced and its similar sequences were observed against the available database, and it was found to be more related to foreign strains. It was confirmed that the plants acquired the infection either during importation or later during close maintenance in the nurseries post-importation. Whereas the wild population of orchids surveyed from the Western Ghat of Kerala, did not test positive for CymMV, they were able to take up the infection upon artificial inoculation. CymMV is highly contagious and can easily transmit through infected plant sap, there is a greater possibility of spread of this virus to other orchids when kept in its vicinity. Even though CymMV was not a quarantined pathogen, there are possibilities of its spread to the native wild orchid population, and it may have unfavourable results, especially in the biodiversity hotspots like the Western Ghats of Kerala.

Unveiling metabolic integration in psyllids and their nutritional endosymbionts through comparative transcriptomics analysis

Psyllids, a group of insects that feed on plant sap, have a symbiotic relationship with an endosymbiont called Carsonella. Carsonella synthesizes essential amino acids and vitamins for its psyllid host, but lacks certain genes required for this process, suggesting a compensatory role of psyllid host genes. To investigate this, gene expression was compared between two psyllid species, Bactericera cockerelli and Diaphorina citri, in specialized cells where Carsonella resides (bacteriomes). Collaborative psyllid genes, including horizontally transferred genes, showed patterns of conserved gene expression; however, species-specific patterns were also observed, suggesting differences in the nutritional metabolism between psyllid species. Also, the recycling of nitrogen in bacteriomes may primarily rely on glutamate dehydrogenase (GDH). Additionally, lineage-specific gene clusters were differentially expressed in B.cockerelli and D.citri bacteriomes and are highlighted here. These findings shed light on potential host adaptations for the regulation of this symbiosis due to host, microbiome, and environmental differences.

Brief windows with more favorable atmospheric conditions explain patterns of Polylepis reticulata tree water use in a high-altitude Andean forest.

Polylepis trees occur throughout the Andean mountain region, and it is the tree genus that grows at the highest elevation worldwide. In the humid Andes where moisture is rarely limiting, Polylepis trees must adapt to extreme environmental conditions, especially rapid fluctuations in temperature, ultraviolet radiation and vapor pressure deficit (VPD). However, Polylepis' water-use patterns remain largely unknown despite the importance of understanding their response to microclimate variation to determine their capacity to maintain resilience under future environmental change. We conducted a study in a Polylepis reticulata Kunth forest in the Ecuadorian Andes to evaluate its tree water-use dynamics and to identify the main environmental drivers of transpiration. Tree sap flow was monitored simultaneously with soil volumetric water content (VWC) and microclimate during 2 years for trees growing in forest edge and interior locations. We found that sap flow was primarily controlled by VPD and that VWC exerted a secondary role in driving sap flow dynamics. The highest values for sap flow rates were found when VPD>0.15kPa and VCW<0.73cm3cm-3, but these threshold conditions only occurred during brief periods of time and were only found in 11% of our measurements. Moreover, these brief windows of more favorable conditions occurred more frequently in forest edge compared with forest interior locations, resulting in edge trees maintaining 46% higher sap flow compared with interior trees. Our results also suggest that P. reticulata has a low stomatal control of transpiration, as the sap flow did not decline with increasing VPD. This research provides valuable information about the potential impacts of projected future increases in VPD due to climate change on P. reticulata water-use dynamics, which include higher sap flow rates leading to greater transpirational water loss due to this species' poor stomatal control.

Anatomy of an agricultural antagonist: Feeding complex structure and function of three xylem sap-feeding insects illuminated with synchrotron-based 3D imaging.

Many insects feed on xylem or phloem sap of vascular plants. Although physical damage to the plant is minimal, the process of insect feeding can transmit lethal viruses and bacterial pathogens. Disparities between insect-mediated pathogen transmission efficiency have been identified among xylem sap-feeding insects; however, the mechanistic drivers of these trends are unclear. Identifying and understanding the structural factors and associated integrated functional components that may ultimately determine these disparities are critical for managing plant diseases. Here, we applied synchrotron-based X-ray microcomputed tomography to digitally reconstruct the morphology of three xylem sap-feeding insect vectors of plant pathogens: Graphocephala atropunctata (blue-green sharpshooter; Hemiptera, Cicadellidae) and Homalodisca vitripennis (glassy-winged sharpshooter; Hemiptera, Cicadellidae), and the spittlebug Philaenus spumarius (meadow spittlebug; Hemiptera, Aphrophoridae). The application of this technique revealed previously undescribed anatomical features of these organisms, such as key components of the salivary complex. The visualization of the 3D structure of the precibarial valve led to new insights into the mechanism of how this structure functions. Morphological disparities with functional implications between taxa were highlighted as well, including the morphology and volume of the cibarial dilator musculature responsible for extracting xylem sap, which has implications for force application capabilities. These morphological insights will be used to target analyses illuminating functional differences in feeding behavior.

Do adult Magicicada (Hemiptera: Cicadidae) feed? Historical perspectives and evidence from molecular gut content analysis.

The periodical cicadas in the genus Magicicada are remarkable for their unusual life histories and dramatic synchronized emergences every 13 or 17 years. While aspects of their evolution, mating behaviors, and general biology have been well-characterized, there is surprising uncertainty surrounding the feeding habits of the short-lived adult stage. Despite a tentative scientific consensus to the contrary, the perception that adult Magicicada do not feed has persisted among the general public, and recent studies are lacking. We directly investigated the feeding behavior of Magicicada spp. through high-throughput sequencing (HTS)-based dietary analysis of nymphs, freshly molted (teneral) adults, and fully sclerotized adults collected from orchard and wooded habitats during the 2021 emergence of Brood X. Identifiable plant DNA (trnF, ITS amplicons) was successfully recovered from nymphs and adults. No plant DNA was recovered from teneral adults, suggesting that all DNA recovered from sclerotized adults was ingested during the post-teneral adult stage. Both nymphs and adults were found to have ingested a range of woody and herbaceous plants across 17 genera and 14 families. Significantly more plant genera per individual were recovered from adults than from nymphs, likely reflecting the greater mobility of the adult stage. We hypothesize that the demonstrated ingestion of plant sap by Magicicada adults is driven by a need to replace lost water and support specialized bacteriome-dwelling endosymbionts that cicadas depend upon for growth and development, which constitutes true feeding behavior.

Energy storage in the forest ecosystem

AbstractInhabitants in the forest ecosystem store energy for their own use and then give it to their predators. There is animal territorialism in the forest ecosystem. Large animals need a larger territory to harvest their needs. Some species mark the boundaries of their territory with their urine to prevent other species from intruding. Natural plant saps are usually the first step of the food chain. Ants, larvae, and flies that consume the natural plant juices are usually the second step of the food chain. Anteaters, larvae‐eating birds, and frogs constitute the third step. Pumas and jaguars, wolves, tigers, and lions eat the anteaters, frogs, and birds. The average exergy efficiency of going from the nth step to n + 1 step is 0.078‐fold of the previous step. Energy storage efficiency of any species depends on the path they follow. The longer the path is, the smaller will be the energy stored by each of the species efficiency down the food chain.

The Response of Chlorophyll Content and Ionic Composition in Tomato and Pepper Seedlings to Foliar Nutrition in Growing Chambers

Studies have shown that applying specific solutions to the leaves of tomato and pepper plants can boost their output by enhancing nutrient absorption. The factorial analysis of two factors was used in data collection and statistical analysis in this experiment. The first factor was the cultivar (Mobil, Korall, and Tyking F1 for tomatoes, and while cultivars of Carma, Fokusz, and Bobita F1 for sweet pepper), and the second was the spray treatment. Sprays used were sodium bicarbonate (0.52%), 50 mg·L−1 salicylic acid, and distilled water. The parameters collected were the SPAD index of chlorophyll and the plant sap’s content of calcium, potassium, and nitrates, with five observations for each record. Salicylic acid 50 mg·L−1 caused the highest multiple contents, particularly in the tomato cultivar Korall. The lowest multiple contents were for the Mobil cultivar. Spraying Mobil with salicylic acid (50 mg·L−1) and sodium bicarbonate (0.52%) produced the lowest chlorophyll and ionic content. Salicylic acid 50 mg·L−1 also led to the highest multiple values, particularly in the Carma pepper cultivar. The results revealed the multiple lowest contents of measured parameters were for the Bobita F1 cultivar. Finally, gardeners should consider growing Korall tomato and Carma pepper with a supportive spraying application of salicylic acid 50 mg·L−1 before seedlings are transferred to an open-air garden. Gardeners should consider the additional production-improving aspects described in existing research and seed manufacturer recommendations.

PENGAMBILAN MINYAK TERPENTIN DARI GETAH PINUS DENGAN METODE MICROWAFE ASSISTED HYDRO-DISTILATION (MAHD)

Turpentine oil is the result of distillation of pine tree sap. The main content of turpentine oil is α-pinene which can be used for the synthesis of organic compounds such as paint and carbolic acid. This study aims to study the process of extracting turpentine oil using the Microwave Hydro-Distillation method. In this research studied the effect of time, power and volume of raw materials in the Microwave Hydro-Distillation process. The variables observed in this study were time (30, 40, 50, 60 and 70 minutes), power (150, 300 and 600 Watt) and raw material volume (150 ml). The quality of turpentine oil such as color, specific gravity, and refractive index were tested according to SNI 7633-2011, while the α-pinene content was analyzed using GC-MS. This study produced the highest yield of 28.22% in the extraction of raw materials of 150 mL using 300 and 600 Watts of power for 70 minutes with 85.01% α-pinene, 5.4% 3-carene and 2.27% β-pinene. Turpentine oil has a characteristic clear color from aquadest solvent with a refractive index of 1.465 and a specific gravity of 0.858 g/cm3, while from hexane solvent with a refractive index of 1.471 and a specific gravity of 0.863 g/cm3. The results of the study concluded that microwave energy has great potential to be used as an energy source for the process of extracting turpentine oil from pine resin because it can produce turpentine oil in a short time.

In vivo sensing to monitor tomato plants in field conditions and optimize crop water management

Irrigation is key to increasing crop yield and meeting the global demand for food. This study reports the assessment of tomato water consumption by bioristor, a new in vivo an Organic ElectroChemical Transistor-based biosensor. Bioristor enables direct, real-time acquisition of biophysical information about the plant’s water requirements directly from the plant sap, and thus the water input can be adjusted accordingly.The aim of this study is to demonstrate the efficacy of bioristor in rapidly detecting changes in the plant’s water status enhancing water use and irrigation efficiency in tomato cultivation with significant savings in the water supply. To this end, experiments were carried out in 2018 and 2020 in Parma (Italy) in tomato fields under different water regimes. The sensor response index (R) produced by bioristor recorded the real time plant health status, highlighting an excess in the water supplied as well as the occurrence of drought stress during the growing season. In both years, bioristor showed that the amount of water supplied could have been reduced by 36% or more. Bioristor also measured the timing and duration of leaf wetting: 438 h and 409 h in 2018 and 2020, respectively. These results open up new perspectives in irrigation efficiency and in more sustainable approaches to pesticide application procedures.

THE EFFECT OF NEEM GUM ON THE REDUCTION IN RAT BLOOD GLUCOSE LEVELS INDUCED BY STREPTOZOTOCIN

Pharmacological therapy for diabetes, which is primarily made up of chemicals, still causes a lot of side effects. The numerous side effects of pharmacological therapy for diabetes have generated innovations in alternative diabetes therapies using ingredients derived from nature. One of the natural ingredients with an anti-hyperglycemia effect is neem gum (NG), or the sap of the neem plant (Azadirachta indica). The aim of this study was to determine the effect of NG on the reduction of blood glucose levels. Moreover, this study had six groups, including a normal control group and groups with doses of 0, 3.75, 7.5, 15, and 30 grams/kgBW. The results showed that NG reduced blood glucose levels in diabetic rats. The paired t-test showed a significant reduction in blood glucose in all groups administered NG except for the dose 3.75 group (P&lt;0.05). The minimum and maximum effective doses of NG were calculated using the quadratic regression test with the equation y = 1.059x2–46.576x+408. With a target blood glucose level of between 80 and 126 mg/dL, the minimum and maximum effective doses of NG were obtained in the range of 12–15 mg/dL. This study concluded that administering NG to diabetic rats can reduce blood glucose levels. Phytochemical studies and research are needed with serial examinations using the effective dose range of neem gum.

Lipid concentration and composition in xylem sap of woody angiosperms from a tropical savanna and a seasonal rainforest

Lipids may play an important role in preventing gas embolisms by coating nanobubbles in xylem sap. Few studies on xylem sap lipids have been reported for temperate plants, and it remain unclear whether sap lipids have adaptational significance in tropical plants. In this study, we quantify the lipid composition of xylem sap for angiosperm species from a tropical savanna (seven species) and a seasonal rainforest (five species) using mass spectrometry. We found that all twelve species studied contained lipids in their xylem sap, including galactolipids, phospholipids and triacylglycerol, with a total lipid concentration ranging from 0.09 to 0.26 nmol/L. There was no difference in lipid concentration or composition between plants from the two sites, and the lipid concentration was negatively related to species’ open vessel volume. Furthermore, savanna species showed little variation in lipid composition between the dry and the rainy season. These results support the hypothesis that xylem sap lipids are derived from the cytoplasm of individual conduit cells, remain trapped inside individual conduits, and undergo few changes in composition over consecutive seasons. A xylem sap lipidomic data set, which includes 12 tropical tree species from this study and 11 temperate tree species from literature, revealed no phylogenetic signals in lipid composition for these species. This study fills a knowledge gap in the lipid content of xylem sap in tropical trees and provides additional support for their common distribution in xylem sap of woody angiosperms. It appears that xylem sap lipids have no adaptive significance.

Promising useful plants of the genus Iris L. in the collection of the Botanical Garden of Peter the Great, cultivation features

Information on biological properties of 11 species of the genus Iris (Iridaceae), on the prospects for their practical use, and the features of their care in the collection is presented. The article is the result of a long-term study of irises in nature and in the Iridarium collection, in addition, extensive literature is used that characterizes the chemical composition and medicinal properties of plants. It has been shown that the resistance of plants themselves to diseases, for example, to bacteriosis, depends on the content of various derivatives of phenolcarboxylic acids plants. If it is higher, theplants are more resistant to bacteriosis, as in I. ensata, I. lactea s. l., I. pseudacorus, I. sibirica. This conclusion is confirmed by the fact that groups of irises that do not have such a quantity of phenolcarboxylic acids derivatives are unstable to bacteriosis, such species are I. aphylla, I. furcata, I. pumila. Plants of I. lactea s. l., I. ruthenica, which have anthelmintic properties, are not affected by nematodes, both rhizomatous and leafy. It was noted that irises with a high content of ascorbic acid in the leaves have winter hardiness (I. setosa - 1218 мг%). Conclusions are drawn, which were confirmed by experience, about the important role of organic acids in plant sap and their resistance to diseases.

Analysis of the Use of Euphorbia tirucalli Sap in the Composition of an Asphalt Bio-emulsion

Abstract The reduction in the availability of materials traditionally used in paving, especially the asphalt binder, requires the development of innovative technologies that allow their total or partial replacement in road construction. This work aims to analyze the development and performance of an asphalt bio-emulsion to be used in chip seals, using a bio-binder partially replaced by petroleum plant sap. For this, a two-stage experimental program was developed. The first stage consisted of sap extraction and manufacture of the bio-binder and bio-emulsion, whereas the second phase involved the rheological characterization of these materials in the dynamic shear rheometer and adhesion tests with the binder bond strength (BBS) test. The results indicated that the addition of sap and the emulsification process of the binder reduced its stiffness and increased its phase angle. In terms of the multiple stress creep recovery test, the addition of sap generated changes only at low frequencies, causing the materials to exhibit similar behaviors. The BBS test shows that the material has a better performance than the conventional one. Therefore, according to the rheological analyses following the emulsion performance grade and adhesion tests, the suitability of the bio-emulsion can be verified for paving services with chip seals.

Penentuan Waktu Sadap Getah Pantung (Dyera lowii) di Lahan Rawa Gambut

Pantung tree (Dyera lowii) is a critically endangered species that grows in peat swamps. Pantung cultivation is not only for commercial purposes but also for species conservation, reforestation and rehabilitation of degraded peat swamp land. One of the benefits of the pantung plant is to use its sap as a material for making pencil erasers, rubber toys and others. This study aims to determine the tapping time of pantung plant sap based on its growth rate. Based on the results of this study, the growth in diameter and height of pantung plants can be described through polynomial equations, i.e: y = -3.825941 + 4.1244995x + (-0.140316)x2 and&#x0D; y = 3.562047 + 0.212857x + 0.72187x2 respectively: The time for tapping pantung plant sap in peat swamp land is when the plant has reached a diameter of 20 cm or has reached a height of 12 meters. Based on the polynomial equation, the tapping time for pantung plant sap is 8 years old, when the pantung plant reaches a diameter of 20.42 cm; or at the age of 10 years, when the plant reaches a height of 12.91 meters

Predicting the Impact of Climate Change on the Geographical Distribution of Leafhopper, Cicadella viridis in China through the MaxEnt Model.

Cicadella viridis (Hemiptera: Cicadellidae) is an omnivorous leafhopper that feeds on plant sap. It significantly reduces the yield of agricultural and forestry crops while feeding or ovipositing on the host plant. In recent years, the rapid expansion of C. viridis has posed a serious threat to agricultural and forestry crops. To study the impact of climate change on the geographical distribution of the leafhopper, the maximum entropy (MaxEnt) model and ArcGIS software, combined with 253 geographic distribution records of the pest and 24 environmental variables, were used, for the first time, to predict the potential distribution of C. viridis in China under conditions of climatic change. The results showed that the currently suitable areas for C. viridis are 29.06-43° N, 65.25-85.15° E, and 93.45-128.85° E, with an estimated area of 11,231,423.79 km2, i.e., 11.66% of China. The Loess Plateau, the North China Plain, and the Shandong Peninsula are the main suitable areas. The potential distribution of the leafhopper for the high and medium suitability areas decreased under each climate scenario (except RCP8.5 in the 2090s). Several key variables that have the most significant effect on the distribution of C. viridis were identified, including the mean annual temperature (Bio1), the standard deviation of temperature seasonality (Bio4), the minimum temperature of the coldest month (Bio6), and the precipitation of the coldest quarter (Bio19). Our research provides important guidance for developing effective monitoring and pest control methods for C. viridis, given the predicted challenges of altered pest dynamics related to future climate change.

Distribution Diaspididae (Insecta) and Control Methods

Scale insects are major pests of crops and ornamental plants, with Diaspididae, Pseudococcidae, and Coccidae being the three most important families. They can cause economic damage by sucking sap, injecting poisons, and transmitting viruses. Mealybugs and soft scales may also cause indirect damage by excreting honeydew onto the plant surface. National phytosanitary services conduct active inspections for these insects, and morphological identification is achievable, but difficult. Diaspididae are a family of fast-breeding insects that suck plant sap and produce a sticky material called pad, which attracts ants. Diaspididae is a type of sap-sucking insect that affects hard-leaved orchids, citrus, ficus, and other plants. Females are aphids and generate wax that provides a protective shield. The shield itself can be circular or extended and can range in color from light to dark brown. Diaspididae produces eggs (up to 3000 pieces) under the shield, from which very small, mobile young individuals hatch. Males have two front wings and can fly to other plants; their life cycle is only a few days long.

First report of 'Candidatus Phytoplasma asteris' associated with witches'-broom disease of Cinnamomum camphora in China.

Camphor tree (Cinnamomum camphora) has a wide distribution in the world and is mainly distributed in the South and southwest in China. It can be used as both a wood and a medicine, with high value in industry, medicine, and ecology. In May 2022, it was observed that the approximately ten to fifteen years old Camphor trees were exhibiting witches'-broom, small leaf morphology and chlorosis, and leaf drop in Panzhihua City, Sichuan Province, China. The witches'-broom symptoms consisted of many small branches with little leaves at the top of branches. It was named C. camphora witches'-broom disease (CCWB) and was found in some areas of Miyi, Yanbian, Renhe Xiqu and Dongqu counties. More than 28% of the plants were infected on the five areas surveyed. Total 100 samples were collected from five areas, with 15 symptomatic plants and 5 asymptomatic plants each area. The lateral stem tissues were observed under a scanning electron microscope (Hitachi S-3000N). The nearly spherical bodies were found in the phloem sieve cells of symptomatic plants. Total DNA extraction was conducted from 0.1 g tissue using the CTAB method (Porebski et al. 1997), ddH2O was used as the negative control, and Dodonaea viscose witches'-broom disease plants were used as the positive control. The nested PCR was employed to amplify the 16S rRNA gene (Lee et al. 1993; Schneider et al. 1993) and PCR amplicon of 1.2 kb were amplified (GenBank accessions OP662614; OP662615; OP662616). The direct PCR specific to the ribosomal protein (rp) gene yielded amplicons of approximately 1.2 kb with primer pair rp(I)F1A and rp(I)R1A (Lee et al. 2003) (GenBank accessions OP649592; OP649593; OP649594). The fragment from 25 symptomatic samples was consistent with the positive control, and asymptomatic plants were negative, confirming an association of a phytoplasma with the disease. A BLAST analysis of the 16S rRNA sequences of CCWB phytoplasma showed that it has a 99.44% similarity with Trema laevigata witches'-broom phytoplasma (GenBank accession MG755412). The rp sequence shared 99.59% identity with rapeseed phyllody phytoplasma (GenBank accession CP055264). An analysis with iPhyClassifier showed that the virtual RFLP pattern derived from the query 16S rDNA fragment of CCWB phytoplasma is most similar to the reference pattern of the 16Sr group I, subgroup B (OY-M, GenBank accession AP006628). The phytoplasma is identified as 'Ca. Phytoplasma asteris'-related strain belonging to sub-group 16SrI-B. The phylogenetic tree was constructed based on 16S rRNA gene and rp gene sequences by using MEGA version 6.0 (Tamura et al. 2013) with neighbor-joining (NJ) method and bootstrap support was estimated with 1000 replicates. The result indicated that the CCWB phytoplasma formed a subclade in 16SrI-B and rpI-B respectively. In addition, the plants were positive for the phytoplasma using nested PCR after grafting for 30 d in nursery conditions. It is noteworthy that the plants were seriously damaged by aphid, Psyllidae and Ceroplastes. It is speculated that the insects of Homoptera typically transmit phytoplasmas by feeding on plant sap, thus it is necessary to control aphids in order to control the C. camphora witches'-broom disease. To the best of our knowledge, Camphor tree is a new host plant of 'Ca. Phytoplasma asteris' in China. The newly emerged disease is a threat to Camphor tree production.

Effect of several reduced-risk insecticides on the population of Bemisia tabaci Genn. and incidence of pepper yellow leaf curl Indonesia virus (PepYLCIV) on chili plants

Tobacco whitefly, Bemisia tabaci Genn. can directly, and indirectly damage chili plants by sucking the plant sap and transmitting Pepper yellow leaf curl Indonesia virus (PepYLCIV), respectively. Farmers control PepYLCIV by using synthetic insecticides with 2-3 applications a week to suppress the vector population. The intensive use of insecticide raises concern about potential detrimental effects on the environment and non-target organisms. An alternative control measure for B. tabaci is the use of reduced-risk insecticides that are effective but safer. Thus, the study aimed to determine the effectiveness of various reduced-risk insecticides in reducing the whitefly population and PepYLCIV incidence. This experiment consisted of 12 treatments using insecticides of abamectin, azadiractin, imidacloprid, deltamethrin, spinosad, and water (control), applied once and twice a week. The results showed that the low-risk insecticides had no significant effect on the numbers of adults and nymphs of B. tabaci and the PepYLCIV incidence. Imidacloprid had significantly lower egg number and PepYLCIV incidence than the control and the other insecticide treatments. Our results also showed that B. tabaci populations were low throughout the season but the incidences of PepYLCIV were relatively high. This indicated a possibility that PepYLCIV is seed-borne.