scholarly journals Insect herbivory facilitates the establishment of an invasive plant pathogen

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Kirstin Arend ◽  
Dominik Begerow ◽  
Derek Peršoh
Keyword(s):  
Invasive Plant ◽  
Pathogenic Fungus ◽  
Feeding Activity ◽  
Insect Herbivory ◽  
Forest Health ◽  
Mechanical Damage ◽  
Pathogenic Fungi ◽  
Fungal Colonization ◽  
Feeding Damage ◽  
The Impact

AbstractPlants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

scholarly journals Ubiquity of Insect-Derived Nitrogen Transfer to Plants by Endophytic Insect-Pathogenic Fungi: an Additional Branch of the Soil Nitrogen Cycle

2013 ◽  
Vol 80 (5) ◽  
pp. 1553-1560 ◽  
Author(s):  
Scott W. Behie ◽  
Michael J. Bidochka
Keyword(s):  
Panicum Virgatum ◽  
Pathogenic Fungus ◽  
Insect Herbivory ◽  
Pathogenic Fungi ◽  
Nitrogen Transfer ◽  
Metarhizium Robertsii ◽  
Content Type ◽  
Lecanicillium Lecanii ◽  
Worldwide Distribution ◽  
Insect Pathogenic Fungi

ABSTRACTThe study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungusMetarhizium robertsii. That is, the endophytic capability and insect pathogenicity ofM. robertsiiare coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in fiveMetarhiziumspecies representing those with broad (M. robertsii,M. brunneum, andM. guizhouense) and narrower insect host ranges (M. acridumandM. flavoviride), as well as the insect-pathogenic fungiBeauveria bassianaandLecanicillium lecanii. Insects were injected with15N-labeled nitrogen, and we tracked the incorporation of15N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. AllMetarhiziumspecies andB. bassianabut notL. lecaniishowed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high,M. robertsiiwas able to transfer insect-derived nitrogen to plants.Metarhiziumspp. andB. bassianahave a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

scholarly journals The Impact of Insect Herbivory in the Level of Cannabinoids in CBD Hemp Varieties

2021 ◽  
Author(s):  
Brandon Jackson ◽  
Lenneisha Gilbert ◽  
Tigist Tolosa ◽  
Shellyann Henry ◽  
Victoria Volkis ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Cannabis Sativa ◽  
Insect Herbivory ◽  
Mechanical Damage ◽  
Dry Weight ◽  
The United States ◽  
Corn Earworm ◽  
Herbivore Damage ◽  
And Control ◽  
The Impact

Abstract Background In the United States, industrial hemp is defined as a Cannabis sativa L. plant not containing more than 0.3% delta-9-tetrahydrocannabinol (D9THC) by dry weight. Plants respond to insect herbivore damage by changing their chemistry to counter the effects of herbivore attack. Here, we hypothesized that the corn earworm (Helicoverpa zea) infestation might impact the level of cannabinoids (Cannabidiol (CBD) and D9THC). Results In a laboratory trial, the CBD hemp, Cherry Blossom, and The Wife varieties were subjected to herbivore damage (HD), Mechanical damage (MD), and Control. After 24hrs of the treatments, we found a significant increase in CBD and D9THC in HD plants compared with MD and Control plants. Similar experiments were conducted in the field condition. A substantial increase in CBD and D9THC observed in herbivore damaged hemp plants compared to the control plants. However, in the field trial, the levels of cannabinoids were not significantly higher in The wife variety. Interestingly, the Corn earworm larvae fed with CBD and D9THC spiked diet showed a significant reduction in body mass, as compared to the larvae fed with the control diets.ConclusionsThe level of cannabinoids seems not genetically fixed somewhat; it is affected by insect herbivory. Our results suggest that CBD hemp plants are exposed to insect herbivory spikes in cannabinoid production and surpass the 0.3 % legal limit of D9THC. The growth and development of Corn earworm, the number one hemp pest in North America affected by cannabinoids. The increased concentration of CBD and D9THC observed in herbivore damaged hemp plants might be associated with the direct deterrence of the corn earworm larvae. Further research underway using different hemp varieties to assess if herbivory and other biotic stressors impact the level of cannabinoids.

scholarly journals Bookkeeping of insect herbivory trends in herbarium specimens of purple loosestrife ( Lythrum salicaria )

2018 ◽  
Vol 374 (1763) ◽  
pp. 20170398 ◽  
Author(s):  
Caroline Beaulieu ◽  
Claude Lavoie ◽  
Raphaël Proulx
Keyword(s):  
Invasive Plant ◽  
Insect Herbivory ◽  
Lythrum Salicaria ◽  
Leaf Damage ◽  
Purple Loosestrife ◽  
Herbarium Specimens ◽  
Feeding Damage ◽  
Voucher Specimens ◽  
Insect Interactions ◽  
Biodiversity Changes

The potential use of herbarium specimens to detect herbivory trends is enormous but largely untapped. The objective of this study was to reconstruct the long-term herbivory pressure on the Eurasian invasive plant, purple loosestrife ( Lythrum salicaria ), by evaluating leaf damage over 1323 specimens from southern Québec (Canada). The hypothesis tested is that that the prevalence of herbivory damage on purple loosestrife is low during the invasion phase and increases throughout the saturation phase. Historical trends suggest a gradual increase in hole feeding and margin feeding damage from 1883 to around 1940, followed by a period of relative stability. The percentage of specimens with window feeding damage did not begin to increase until the end of the twentieth century, from 3% (2–6%) in 1990 to 45% (14–81%) in 2015. Temporal changes in the frequency of window feeding damage support the hypothesis of an increasing herbivory pressure by recently introduced insects. This study shows that leaf damage made by insects introduced for the biocontrol of purple loosestrife, such as coleopterans of the Neogalerucella genus, can be assessed from voucher specimens. Herbaria are a rich source in information that can be used to answer questions related to plant-insect interactions in the context of biological invasions and biodiversity changes. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the Anthropocene’.

ORTHOSIA HIBISCI GUENÉE (LEPIDOPTERA: NOCTUIDAE): INDIGENOUS PARASITOIDS AND THE IMPACT OF EARINUS LIMITARUS (SAY) (HYMENOPTERA: ICHNEUMONIDAE) ON ITS HOST FEEDING ACTIVITY

1995 ◽  
Vol 127 (4) ◽  
pp. 473-477 ◽  
Author(s):  
J.E. Cossentine ◽  
L.B. Jensen
Keyword(s):  
British Columbia ◽  
Feeding Activity ◽  
Host Feeding ◽  
Feeding Damage ◽  
The South ◽  
Minor Significance ◽  
Compsilura Concinnata ◽  
The Impact ◽  
Lepidoptera Noctuidae ◽  
Indigenous Parasitoids

AbstractA 3-year survey of apple and cherry orchards in the interior of British Columbia revealed that speckled green fruitworm, Orthosia hibisci, is the dominant fruitworm species in the south of the Okanagan Valley. Larvae of speckled green fruitworm collected from orchards that used no or minimal insecticides experienced 22.5–29.0% parasitism in 1988–1990. Earinus limitarus was responsible for 98.9% of the parasitism in the 3 years. Parasitoids of minor significance included a Meteorus sp. (Hymenoptera: Braconidae) and Compsilura concinnata (Mg.) (Diptera: Tachinidae). Data from laboratory trials indicated that feeding by O. hibisci in the fifth and sixth instars was significantly (P < 0.05) reduced when larvae were parasitized by E. limitarus. Orthosia hibisci in the second through sixth instars in sleeve cages damaged developing apples in the field. Earinus limitarus appears able to reduce O. hibisci numbers for the following year as well as immediate host feeding damage in at least the last two instars.

scholarly journals In the tripartite combination Botrytis cinerea–Arabidopsis–Eurydema oleracea, the fungal pathogen alters the plant–insect interaction via jasmonic acid signalling activation and inducible plant-emitted volatiles

2021 ◽  
Author(s):  
Luisa Ederli ◽  
Gianandrea Salerno ◽  
Mara Quaglia
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Abiotic Factor ◽  
Feeding Damage ◽  
Plant Volatile ◽  
Long Time ◽  
Insect Interactions ◽  
Plant Choice ◽  
The Impact

AbstractIn ecosystems, plants are continuously challenged by combined stress conditions more than by a single biotic or abiotic factor. Consequently, in recent years studies on plant relationships with multiple stresses have aroused increasing interest. Here, the impact of inoculation with fungal pathogens with different lifestyles on Arabidopsis plants response to the following infestation with the invasive crop pest Eurydema oleracea was investigated. In particular, as fungal pathogens the necrotroph Botrytis cinerea and the biotroph Golovinomyces orontii were used. Plants exposed to B. cinerea, but not to G. orontii, showed reduced herbivore feeding damage. This difference was associated to different hormonal pathways triggered by the pathogens: G. orontii only induced the salicylate-mediated pathway, while B. cinerea stimulated also the jasmonate-dependent signalling, which persisted for a long time providing a long-term defence to further herbivore attack. In particular, the lower susceptibility of B. cinerea-infected Arabidopsis plants to E. oleracea was related to the stimulation of the JA-induced pathway on the production of plant volatile compounds, since treatment with VOCs emitted by B. cinerea inoculated plants inhibited both insect plant choice and feeding damage. These results indicate that necrotrophic plant pathogenic fungi modulate host volatile emission, thus affecting plant response to subsequent insect, thereby increasing the knowledge on tripartite plant–microbe–insect interactions in nature.

Glycoconjugates on the surface of spores of the pathogenic fungus Phytophthora cinnamomi studied using fluorescence and electron microscopy and flow cytometry

1990 ◽  
Vol 36 (3) ◽  
pp. 183-192 ◽  
Author(s):  
A. R. Hardham ◽  
E. Suzaki
Keyword(s):  
Flow Cytometry ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Phytophthora Cinnamomi ◽  
Pathogenic Fungus ◽  
Fluorescein Isothiocyanate ◽  
Pathogenic Fungi ◽  
Surface Flow ◽  
Soybean Agglutinin ◽  
Binding Material

Glycoconjugates on the surface of zoospores and cysts of the pathogenic fungus Phytophthora cinnamomi have been studied using fluorescein isothiocyanate labelled lectins for fluorescence microscopy and flow cytometry, and ferritin- and gold-labelled lectins for ultrastructural analysis. Of the five lectins used, only concanavalin A (ConA) binds to the surface of the zoospores, including the flagella and water expulsion vacuole. This suggests that of accessible saccharides, glucosyl or mannosyl residues predominate on the outer surface of the zoospore plasma membrane. Early in encystment, a system of flat disc-like cisternae, which underlie the zoospore plasma membrane, vesiculate. These and other small peripheral vesicles quickly disappear. After the induction of encystment, ConA is no longer localised close to the plasma membrane but binds to material loosely associated with the cell surface. Quantitative measurements by flow cytometry indicate that the ConA-binding material is gradually lost from the cell surface. The cyst wall is weakly labelled, but the site of germ tube emergence stains intensely. During the first 2 min after the induction of encystment, material that binds soybean agglutinin, Helix pommatia agglutinin, and peanut agglutinin appears on the surface of the fungal cells. The distribution of this material, rich in galactosyl or N-acetyl-D-galactosaminosyl residues, is initially patchy, but by 5 min the material evenly coats most of the cell surface. Labelling of zoospores in which intracellular sites are accessible indicates that the soybean agglutinin binding material is stored in vesicles that lie beneath the plasma membrane. Quantitation of soybean agglutinin labelling shows that maximum binding occurs 2–3 min after the induction of encystment. Key words: cell surface, flow cytometry, lectins, pathogenic fungi, Phytophthora cinnamomi.

Dynamics of fungal pathogens in host plant tissues

1995 ◽  
Vol 73 (S1) ◽  
pp. 1275-1283 ◽  
Author(s):  
Shigehito Takenaka
Keyword(s):  
Host Plant ◽  
Species Interactions ◽  
Fungal Biomass ◽  
Quantitative Methods ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Molecular Methods ◽  
Plant Colonization ◽  
Fungal Colonization ◽  
Plant Tissues

To develop efficient control measures against fungal plant pathogens, the dynamics of host plant colonization during disease development and the interactions among fungi within host plant tissues need to be clarified. These studies require accurate quantitative estimation of specific fungal biomass in plant tissues. This has been approached by direct-microscopic methods, cultural methods, chemical determinations of fungal components, serological methods, and molecular methods. Among these methods, serological and molecular methods provide rapid, specific, and sensitive quantitative measures of fungal biomass in host plant tissues. Therefore, studies on fungal dynamics of host plant colonization using these two methods are presented. Some examples of species interactions among pathogenic fungi within host plants, such as synergism and competition, are reviewed and the usefulness of serological and molecular methods for studies on these interactions is presented. These quantitative methods will provide helpful information for understanding the ecology of plant pathogenic fungi, such as the dynamics of host plant colonization and species interactions. Key words: quantitative methods, fungal biomass, ELISA, PCR, fungal colonization, species interaction.

Road barriers: modern solutions for improving traffic safety

2021 ◽  
pp. 43-48
Author(s):  
Keyword(s):  
Traffic Safety ◽  
Traffic Accident ◽  
Preventive Measures ◽  
Mechanical Damage ◽  
Road Accidents ◽  
Road Users ◽  
Urgent Task ◽  
The Moment ◽  
Energy Absorbing ◽  
The Impact

Improving the system of preventive measures aimed at reducing the severity of the consequences of road accidents is an urgent task. Road deaths are constantly increasing and there is a need for a comprehensive approach to creating safe road conditions. The purpose of this study is to analyze the promising designs of road barriers designed to prevent uncontrolled exit of vehicles from the roadway of the highway and to develop the design of energy-absorbing fencing. Barrier barriers must not only be safe for road users, but must also ensure their safety, as well as preserve the elements after hitting the fence. Analytical studies have shown that in order to reduce mechanical damage to vehicles and reduce the severity of injuries to the driver and passengers, it is necessary to develop a road fence design that allows you to extinguish the impact energy at the moment of contact between the car and the fence. Keywords: fencing, barrier, safety, traffic accident

Harvesting and Threshing Methods on Seed Quality of Dhaincha (Sesbania aculeata)

2021 ◽  
Author(s):  
P. Masilamani ◽  
T. Eevera ◽  
T. Ramesh ◽  
S. Venkatesan
Keyword(s):  
Tamil Nadu ◽  
Seed Quality ◽  
Block Design ◽  
Mechanical Damage ◽  
Shoot Length ◽  
Seedling Vigour ◽  
Root And Shoot Length ◽  
Significant Difference ◽  
Combine Harvester ◽  
The Impact

Background: The present investigation is an attempt to study the effect of different harvesting and threshing methods on germination and seedling vigour of dhaincha. The use of a combine harvester to harvest dhaincha will be an effective alternative method that has not been widely tried. However, work on different methods of harvesting and threshing of dhaincha is limited. Hence, a study was conducted to evaluate the impact of various harvesting and threshing methods on germination and seedling vigour of dhaincha. Methods: This study was conducted at Anbil Dharmalingam Agricultural College and Research Institute, TNAU, Tiruchirappalli, Tamil Nadu. The dhaincha crop was harvested and threshed using four different methods viz., manual harvesting and manual threshing, manual harvesting and threshing by tractor treading, manual harvesting and mechanical threshing and harvesting and threshing by combine harvester. The resultant seeds were tested for mechanical damage and germination potential. The experiment was laid in completely randomized block design. Germination was tested by roll towel method using 100 seeds in four replications. Germination percentage, root and shoot length were measured in seven days after sowing from ten randomly selected seedlings in each replication. For the estimation of dry matter production, ten seedlings were selected at random and kept in a hot air oven maintained at 85oC for 24 hours after measuring their root and shoot length and vigour index was calculated. Mechanical damage to seeds was observed by ferric chloride test. Seed recovery per cent was calculated based on the 100 kgs of dhaincha seeds were cleaned and graded treatment wise using cleaner cum grader and the seeds retained on the bottom sieve were weighed and expressed as per cent of total quantity of seed. Result: The results revealed that the significant difference was found among the different harvesting and threshing methods. The seeds harvested and threshed by manual method recorded 85 per cent germination followed by seeds harvested manually and threshed by mechanical threshing (84 per cent) and seeds harvested manually and threshed by tractor treading (80.5 per cent). The lowest germination of 80.0 per cent was recorded by combine harvesting. From this study, it could be inferred that combine harvester is a modern method for harvesting of dhaincha that saves time and labour when compared to all other methods.

scholarly journals Ecological Impacts of Megaprojects: Species Succession and Functional Composition

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2411
Author(s):  
Hamada E. Ali ◽  
Solveig Franziska Bucher
Keyword(s):  
Plant Species ◽  
Large Scale ◽  
Invasive Plant ◽  
Species Traits ◽  
Natural Vegetation ◽  
Ecological Impacts ◽  
Imperata Cylindrica ◽  
Dry Matter Content ◽  
Large Scale Disturbance ◽  
The Impact

Land-use changes have huge impacts on natural vegetation, especially megaprojects, as the vegetation layer is destroyed in the course of construction works affecting the plant community composition and functionality. This large-scale disturbance might be a gateway for the establishment of invasive plant species, which can outcompete the natural flora. In contrast, species occurring in the area before the construction are not able to re-establish. In this study, we analyzed the impact of a pipeline construction on a wetland nature reserve located in northern Egypt. Therefore, we analyzed the plant species occurrence and abundance and measured each plant species’ traits before the construction in 2017 as well as on multiple occasions up to 2 years after the construction had finished on altogether five sampling events. We found that the construction activity led to the establishment of an invasive species which previously did not occur in the area, namely, Imperata cylindrica, whereas five species (Ipomoea carnea, Pluchea dioscoridis, Polygonum equisetiforme, Tamarix nilotica, and Typha domingensis) could not re-establish after the disturbance. The functionality of ecosystems assessed via the analysis of plant functional traits (plant height, specific leaf area, and leaf dry matter content) changed within species over all sampling events and within the community showing a tendency to approximate pre-construction values. Functional dispersion and Rao’s quadratic diversity were higher after the megaproject than before. These findings are important to capture possible re-establishment and recovery of natural vegetation after construction and raise awareness to the impact of megaprojects, especially in areas which are high priority for conservation.

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