scholarly journals Lack of Evidence for Transmission of Verticillium dahliae by the Olive Bark Beetle Phloeotribus scarabaeoides in Olive Trees

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 534
Author(s):  
Ibrahim ElDesouki-Arafat ◽  
Hani K. Aldebis-Albunnai ◽  
Enrique Vargas-Osuna ◽  
Antonio Trapero ◽  
Francisco J. López-Escudero
Keyword(s):  
Bark Beetle ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Bark Beetles ◽  
Mediterranean Area ◽  
Molecular Techniques ◽  
Experimental Conditions ◽  
Mosquito Net ◽  
Phloeotribus Scarabaeoides ◽  
Olive Trees

Verticillium wilt of olive, caused by Verticillium dahliae Kleb., is one of the most important diseases affecting olive crops in the Mediterranean area. With the aim to evaluate the role of Phloeotribus scarabaeoides (Bernard) (olive bark beetle) as a dispersal vector of V. dahliae, several experiments were conducted in semi-controlled conditions from May 2009 to April 2012. Groups of olive trees (2.5-year-old) certified free from V. dahliae were covered by a mosquito net and exposed to adults of P. scarabaeoides by three different ways: (1) branches or trunks collected in several olive orchards from trees severely affected by Verticillium wilt and showing apparent entry holes (mating galleries) of P. scarabaeoides; (2) adults of olive bark beetle extracted from damaged branches collected in the field; (3) adults from damaged branches that were superficially inoculated with V. dahliae. The fungus V. dahliae was not detected either by microbiological and molecular techniques from shoots of olive trees with galleries of the insect or from any of the tissues of the collected beetle adults from the galleries. Additionally, Verticillium wilt disease symptoms were not observed in olive trees exposed to the olive bark beetles. Moreover, the pathogen was never detected from any beetle adults that were recovered from the mating galleries of branches or trunks collected in several olive orchards from trees severely affected by Verticillium wilt. We conclude that P. scarabaeoides is not a vector of V. dahliae under the investigated experimental conditions.

scholarly journals Monitoring of Population of Scolytinae in Olive Culture

2018 ◽  
Vol 10 (8) ◽  
pp. 457 ◽  
Author(s):  
Jéssica Maus Da Silva ◽  
Ervandil Corrêa Costa ◽  
Eli Nunes Marques ◽  
Emanuel Arnoni Costa
Keyword(s):  
Experimental Design ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Economic Interest ◽  
Border Area ◽  
Phloeotribus Scarabaeoides ◽  
Pest Insects ◽  
Randomized Experimental Design ◽  
Border Areas ◽  
Olive Trees

Monitoring of insects is important to analyze the species present in culture of economic interest, to verify the period of highest incidence and quantify the damages caused by the pest insects. Here, we aim to assess the diversity of bark beetles in an olive orchard. The experiment was assessed in fortnightly series throughout a year and conducted with a completely randomized experimental design, consisting of three treatments: T1: homogeneous olive culture; T2: heterogeneous olive culture; T3: border area. An ethanol trap was used for the sampling of bark beetles. The species Hypothenemus eruditus, Xyleborus linearicolis and Hypothenemus seriatus showed greater abundance among the treatments. The decrease of abundance, diversity and dominance of bark beetles occurred in the heterogeneous culture (T2). Homogeneous cultures (T1) are more susceptible to the attack of pest-insects due to the lower ecological balance among associate, predator or parasitoid insects. Border areas (T3) showed an increased diversity of arboreal species, favoring the higher incidence of insects. In spring, there is a greater incidence of bark beetles, what reinforces the need for monitoring during this period. So far, there are no evidences of bark beetles infesting olive trees in the area, or the presence of Phloeotribus scarabaeoides, which is the pest bark beetle of olive cultures.

scholarly journals Using a Loop-Mediated Isothermal Amplification (LAMP) Assay and Direct DNA Extraction Method from Wood for Rapid Detection of Verticillium dahliae in Olive Trees

2017 ◽  
Vol 14 (2) ◽  
pp. 727-734
Author(s):  
Saba Aslani ◽  
Ghasemali Garoosi ◽  
Hossein Jafary
Keyword(s):  
Dna Extraction ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Lamp Assay ◽  
Cost Effective ◽  
Pathogenic Fungi ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Minimum Requirements ◽  
Olive Trees

ABSTRACT: Verticillium wilt, which is caused by the fungus Verticillium dahliae, is one of the most important olive diseases worldwide. There are many ways to extract DNA from plant pathogenic fungi and from plant tissues for molecular-based diagnostic assays. LAMP is a new and sensitive molecular-based technique used for detection of plant pathogenic agents with minimum requirements needed. In this study, we tried to achieve a simple, cost effective and efficient method of DNA extraction from both Verticillium dahliae fungus and from infected wood samples in order to run a loop-mediated isothermal amplification (LAMP) assay. Efficiency of three DNA isolation methods from both mycelia and infected wood samples was evaluated. For this purpose, wood samples from infected olive trees were collected from Tarom region in Zanjan province and the samples were cultured on the media. The fungus was isolated and identified as V. dahliae based on morphological features. Then the genomic DNA was extracted using traditional CTAB method, fast NaOH method and direct isolation method from infected wood samples. After assessment of the quality and the quantity of the extracted DNA samples, a LAMP assay was ran using specific primer pairs and the DNA templates extracted using three different methods. In spite of the significant differences in the quantity of DNA samples, LAMP assay could successfully detect the fungus in all samples. The improved direct isolation of the DNA of V. dahlia from infected wood, followed by a LAMP assay could considerably shortened the detection process of the fungus and hence is a suitable method for screening of olive trees and saplings against Verticillium wilt disease.

scholarly journals Relationship Between the Inoculum Density of Verticillium dahliae and the Progress of Verticillium Wilt of Olive

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1372-1378 ◽  
Author(s):  
F. J. López-Escudero ◽  
M. A. Blanco-López
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Disease Incidence ◽  
Olive Tree ◽  
Temporal Variations ◽  
Inoculum Density ◽  
Infested Soil ◽  
Initial Inoculum ◽  
Progress Curve ◽  
Olive Trees

An experiment was conducted in microplots which were artificially infested with a defoliating isolate of Verticillium dahliae using seven different treatments of inoculum densities ranging from 0 to 10 microsclerotia per gram of soil (ppg). The experiment was conducted in Andalucía (southern Spain), and the susceptible Spanish olive cv. Picual was used to determine the relationship between pathogen inoculum density and the progress of Verticillium wilt of olive (VWO). The inoculum, produced on a sodium pectate cellophane medium, was found to efficiently infect olive trees. Symptoms first appeared 30 weeks after the trees were transplanted into infested soil. Periods of increasing disease incidence in the following seasons and years were mainly during spring and autumn, particularly in the second year after planting. Olive trees exhibited a high susceptibility to the defoliating pathotype of the pathogen, even at very low inoculum levels; in fact, diseased plants were encountered throughout the experiment regardless of the inoculum density treatment. Inoculum densities greater than 3 ppg in the soil resulted in final disease incidence greater than 50% for the trees after 2.5 years. Therefore, these inoculum densities must be considered very high for olive trees. There were no differences in final disease incidence, mean symptom severity, or area under the disease progress curve between plots infested with 10 or 3.33 ppg, whereas other treatments exhibited lower values for each of these disease parameters. The temporal variations of disease incidence and severity were highly correlated for the higher inoculum density treatments, with r2 values ranging from 0.92 to 0.84 for disease incidence and from 0.93 to 0.88 for severity. However, r2 was slightly lower for the treatments involving lower inoculum densities of the pathogen in microplots. The slopes of the linear regression curves were statistically different for nearly all the inoculum density treatments. Positive correlation was found between the initial inoculum density and final disease incidence values after the study period that was accurately explained by mathematical models. The results suggest that susceptible olive cultivars should not be planted in soils infested with virulent defoliating pathotypes of V. dahliae. Results also clarify that inoculum density levels obtained from field soil analyses can be used for establishing a risk prediction system with a view to controlling VWO in olive tree plantations.

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae on Olive Trees in Croatia

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2526-2526 ◽  
Author(s):  
J. Kaliterna ◽  
T. Milicevic ◽  
D. Bencic ◽  
A. Mesic
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
First Report ◽  
Olive Trees

Diversity and distribution of nematodes associated with bark beetles in Israel

Nematology ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 875-886 ◽  
Author(s):  
Qing Xue ◽  
Ofer Slonim ◽  
Patricia Bucki ◽  
Zvi Mendel ◽  
Alex Protasov ◽  
...  
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Host Plants ◽  
Morphological Characteristics ◽  
Nematode Species ◽  
Fruit Tree ◽  
Forest Plantations ◽  
Phloeotribus Scarabaeoides ◽  
Nematode Diversity ◽  
First Time

Summary Bark beetles (Curculionidae: Scolytinae) have a significant economic impact on forest stands and agricultural settings in Israel. We focus on nematodes associated with bark beetles collected from different host plants attacked by Scolytinae. The sampling was conducted in forest plantations and fruit tree orchards in several areas in Israel. A total of 430 beetle specimens of eight species were examined for the presence of nematodes. Fifteen nematode species were detected and identified based on molecular and morphological characteristics. Among the examined scolytids, the pine bark beetle, Orthotomicus erosus, the most widely distributed and frequently occurring species in Israel, was accompanied by the highest nematode diversity, with 11 species recovered. Nematode associations with the almond bark beetle (Scolytus amygdali), the olive bark beetle (Phloeotribus scarabaeoides) and the fig bark beetle (Hypoborus ficus) were recorded for the first time. Our study thus supplies novel information on scolytid-associated nematodes in Israel.

scholarly journals Assessment of Maternal Effects and Genetic Variability in Resistance to Verticillium dahliae in Olive Progenies

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1534
Author(s):  
Pedro Valverde Caballero ◽  
Carlos Trapero Ramírez ◽  
Diego Barranco Navero ◽  
Francisco J. López-Escudero ◽  
Ana Gordon Bermúdez-Coronel ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Control Method ◽  
Integrated Management ◽  
Genetic Resistance ◽  
Resistance Mechanisms ◽  
Plant Diseases ◽  
Conidial Suspension ◽  
Reciprocal Crosses ◽  
Olive Trees

The use of genetic resistance is likely the most efficient, economically convenient and environmentally friendly control method for plant diseases, as well as a fundamental piece in an integrated management strategy. This is particularly important for woody crops affected by diseases in which mainly horizontal resistance mechanisms are operative, such as Verticillium wilt, caused by Verticillium dahliae. In this study, we analyzed the variability in resistance to Verticillium wilt of olive trees in progenies from five crosses: ‘Picual’ × ‘Frantoio’, ‘Arbosana’ × ‘Koroneiki’, ‘Sikitita’ × ‘Arbosana’, ‘Arbosana’ × ‘Frantoio’ and ‘Arbosana’ × ‘Arbequina’ and their respective reciprocal crosses. Additionally, seedlings of ‘Picual’ and ‘Frantoio’ in open pollination were used as controls. In October 2016 and 2018, the fruits were harvested, and seeds germinated. Six-week-old seedlings were inoculated by dipping their bare roots in a conidial suspension of V. dahliae, and disease progress in terms of symptom severity and mortality was evaluated weekly. Additionally, seedling growth was evaluated every two weeks. At the end of the experiment, no significant differences were found for any of the assessed parameters when reciprocal crosses were compared. These results suggest that there is no maternal or paternal effect in regard to the heritability of resistance. In addition, this study identifies the best crosses for obtaining the highest number of resistant genotypes, highlighting the importance of the selection of specific cultivars to optimize the breeding process.

scholarly journals Analytical Characterization of Water-Soluble Constituents in Olive-Derived By-Products

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1299
Author(s):  
Pablo Doménech ◽  
Aleta Duque ◽  
Isabel Higueras ◽  
José Luis Fernández ◽  
Paloma Manzanares
Keyword(s):  
Olive Tree ◽  
Mediterranean Area ◽  
Water Soluble ◽  
Olive Pomace ◽  
Olive Leaves ◽  
Olive Stone ◽  
Olive Trees ◽  
Tree Pruning ◽  
By Products

Olive trees constitute one of the largest agroindustries in the Mediterranean area, and their cultivation generates a diverse pool of biomass by-products such as olive tree pruning (OTP), olive leaves (OL), olive stone (OS), and extracted olive pomace (EOP). These lignocellulosic materials have varying compositions and potential utilization strategies within a biorefinery context. The aim of this work was to carry out an integral analysis of the aqueous extractives fraction of these biomasses. Several analytical methods were applied in order to fully characterize this fraction to varying extents: a mass closure of >80% was reached for EOP, >76% for OTP, >65% for OS, and >52% for OL. Among the compounds detected, xylooligosaccharides, mannitol, 3,4-dihydroxyphenylglycol, and hydroxytyrosol were noted as potential enhancers of the valorization of said by-products. The extraction of these compounds is expected to be more favorable for OTP, OL, and EOP, given their high extractives content, and is compatible with other utilization strategies such as the bioconversion of the lignocellulosic fraction into biofuels and bioproducts.

scholarly journals GhKWL1 Upregulates GhERF105 but Its Function Is Impaired by Binding with VdISC1, a Pathogenic Effector of Verticillium dahliae

2021 ◽  
Vol 22 (14) ◽  
pp. 7328
Author(s):  
Yang Chen ◽  
Mi Zhang ◽  
Lei Wang ◽  
Xiaohan Yu ◽  
Xianbi Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Plants ◽  
Gossypium Hirsutum ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Defense Response ◽  
Upland Cotton ◽  
Effector Protein ◽  
Positive Regulator ◽  
Its Gene

Verticillium wilt, caused by Verticillium dahliae, is a devastating disease for many important crops, including cotton. Kiwellins (KWLs), a group of cysteine-rich proteins synthesized in many plants, have been shown to be involved in response to various phytopathogens. To evaluate genes for their function in resistance to Verticillium wilt, we investigated KWL homologs in cotton. Thirty-five KWL genes (GhKWLs) were identified from the genome of upland cotton (Gossypium hirsutum). Among them, GhKWL1 was shown to be localized in nucleus and cytosol, and its gene expression is induced by the infection of V. dahliae. We revealed that GhKWL1 was a positive regulator of GhERF105. Silencing of GhKWL1 resulted in a decrease, whereas overexpression led to an increase in resistance of transgenic plants to Verticillium wilt. Interestingly, through binding to GhKWL1, the pathogenic effector protein VdISC1 produced by V. dahliae could impair the defense response mediated by GhKWL1. Therefore, our study suggests there is a GhKWL1-mediated defense response in cotton, which can be hijacked by V. dahliae through the interaction of VdISC1 with GhKWL1.

scholarly journals Drivers of Spruce Bark Beetle (Ips typographus) Infestations on Downed Trees after Severe Windthrow

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1290
Author(s):  
Branislav Hroššo ◽  
Pavel Mezei ◽  
Mária Potterf ◽  
Andrej Majdák ◽  
Miroslav Blaženec ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Ips Typographus ◽  
Wind Damage ◽  
Stem Length ◽  
Local Conditions ◽  
Spruce Bark Beetle ◽  
Management Actions ◽  
Spruce Bark

Research Highlights: Bark beetles are important agents of disturbance regimes in temperate forests, and specifically in a connected wind-bark beetle disturbance system. Large-scale windthrows trigger population growth of the European spruce bark beetle (Ips typographus L.) from endemic to epidemic levels, thereby allowing the killing of Norway spruce trees over several consecutive years. Background and Objectives: There is a lack of evidence to differentiate how outbreaks are promoted by the effects of environmental variables versus beetle preferences of trees from endemic to outbreak. However, little is known about how individual downed-tree characteristics and local conditions such as tree orientation and solar radiation affect beetle colonization of downed trees. Materials and Methods: To answer this question, we investigated the infestation rates and determined tree death categories (uprooted, broken, and stump) in wind-damaged areas in Western Tatra Mts. in Carpathians (Slovakia) from 2014–2016, following a windthrow in May 2014. In total, we investigated 225 trees over eight transects. For every tree, we measured its morphological (tree height, crown characteristics), environmental (solar radiation, terrain conditions, trunk zenith), temporal (time since wind damage), and beetle infestation (presence, location of attack, bark desiccation) parameters. We applied Generalized Additive Mixed Models (GAMM) to unravel the main drivers of I. typographus infestations. Results: Over the first year, beetles preferred to attack broken trees and sun-exposed trunk sides over uprooted trees; the infestation on shaded sides started in the second year along with the infestation of uprooted trees with lower desiccation rates. We found that time since wind damage, stem length, and incident solar radiation increased the probability of beetle infestation, although both solar radiation and trunk zenith exhibited nonlinear variability. Our novel variable trunk zenith appeared to be an important predictor of bark beetle infestation probability. We conclude that trunk zenith as a simple measure defining the position of downed trees over the terrain can anticipate beetle infestation. Conclusions: Our findings contribute to understanding of the bark beetle’s preferences to colonize windthrown trees in the initial years after the primary wind damage. Further, our findings can help to identify trees that are most susceptible to beetle infestation and to prioritize management actions to control beetle population while maintaining biodiversity.

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