scholarly journals Sites and Time of Oviposition of Euphyllura phillyreae Foerster on Olive Trees and οon Phillyrea latifolia

2017 ◽  
Vol 11 ◽  
pp. 3
Author(s):  
D.A. Prophretou-Athanasiadou ◽  
M.E Tzanakakis
Keyword(s):  
Laboratory Experiments ◽  
Oviposition Preference ◽  
Flower Buds ◽  
Northern Greece ◽  
Apical Bud ◽  
Stage Of Development ◽  
Phillyrea Latifolia ◽  
Inner Surface ◽  
Olive Trees ◽  
Axillary Leaf

The distribution of eggs of Euphyllura phillyreae Foerster (Homoptera: Aphalaridae) was recorded on twigs of olive trees and of Phillyrea latifolia L. in various locations of the Thessaloniki and Halkidiki prefectures of coastal northern Greece. On olive, the first eggs were observed in the last ten days of March and oviposition was intensified and became abundant only when the apical bud and the axillary leaf and flower buds started to swell. Eggs were laid mostly on swollen buds and on developing inflorescences. Oviposition preference was related to the stage of development of a bud and not to its location on the olive twig. On swollen leaf buds, most eggs were laid on the inner (upper) surface of the middle (second) pair of developing leaves, and fewer on the inner surface of the outer (first) pair and on the innermost (third) pair of leaves. On Phillyrea, eggs were deposited much earlier than on olive, on developing inflorescences. In choice and no-choice laboratory experiments, more eggs were laid on olive twigs bearing developing inflorescences, fewer eggs on twigs bearing only swollen terminal or axillary buds, and no eggs at all on twigs with only fully developed leaves of the previous year.

scholarly journals Virus Surveys in Olive Orchards in Greece Identify Olive Virus T, a Novel Member of the Genus Tepovirus

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 574
Author(s):  
Evanthia Xylogianni ◽  
Paolo Margaria ◽  
Dennis Knierim ◽  
Kyriaki Sareli ◽  
Stephan Winter ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Leaf Roll ◽  
Virus Infections ◽  
Northern Greece ◽  
Coat Protein Region ◽  
Cherry Leaf Roll Virus ◽  
Leaf Yellowing ◽  
Olive Trees ◽  
Olive Varieties ◽  
Viral Sequences

Field surveys were conducted in Greek olive orchards from 2017 to 2020 to collect information on the sanitary status of the trees. Using a high-throughput sequencing approach, viral sequences were identified in total RNA extracts from several trees and assembled to reconstruct the complete genomes of two isolates of a new viral species of the genus Tepovirus (Betaflexiviridae), for which the name olive virus T (OlVT) is proposed. A reverse transcription–polymerase chain reaction assay was developed which detected OlVT in samples collected in olive growing regions in Central and Northern Greece, showing a virus prevalence of 4.4% in the olive trees screened. Sequences of amplified fragments from the movement–coat protein region of OlVT isolates varied from 75.64% to 99.35%. Three olive varieties (Koroneiki, Arbequina and Frantoio) were infected with OlVT via grafting to confirm a graft-transmissible agent, but virus infections remained latent. In addition, cucumber mosaic virus, olive leaf yellowing-associated virus and cherry leaf roll virus were identified.

scholarly journals Diversity of Colletotrichum Species Associated with Olive Anthracnose and New Perspectives on Controlling the Disease in Portugal

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 301 ◽  
Author(s):  
Patrick Materatski ◽  
Carla Varanda ◽  
Teresa Carvalho ◽  
António Bento Dias ◽  
M. Doroteia Campos ◽  
...  
Keyword(s):  
Severe Disease ◽  
Colletotrichum Acutatum ◽  
High Similarity ◽  
Flower Buds ◽  
Vegetative Organs ◽  
Nucleotide Mutation ◽  
Olive Cultivars ◽  
Colletotrichum Spp ◽  
Olive Trees ◽  
Working Out

Olive anthracnose is a very common and severe disease caused by diverse species of fungi belonging to Colletotrichum acutatum and Colletotrichum gloeosporioides complexes. To understand aspects of the Colletotrichum colonization and primary infection in olives, Colletotrichum spp. were isolated from the interior of 2-year stems, flower buds, and immature fruits of three important olive cultivars, Galega vulgar, Cobrançosa, and Azeiteira, from different sites within Alentejo, a major olive-producing region in Portugal. A total of 270 trees was sampled, and 68 Colletotrichum spp. isolates were obtained from 46 olive trees. DNA extraction and amplification of β-tubulin and GADPH genes through PCR revealed that the vast majority of the isolates showed high similarity to Colletotrichum nymphaeae, and only three isolates showed high similarity to Colletotrichum godetiae. The highest number of Colletotrichum spp. isolates was detected in olive trees from Galega vulgar and in immature fruits. No significant differences in the number of Colletotrichum spp. isolates were found in trees from different sites. The highest percentages of infected immature fruits were obtained in trees that also presented a high percentage of 2-year stem infections, which may indicate that 2-year stems serve as important sources of inoculum, and the fungus may travel from the stems to other parts of the plant. Another indication of such possibility is that one isolate of C. nymphaeae (C. nymphaeae 2), characterized by a unique nucleotide mutation within the beta tubulin gene, was present in different organs of the same tree, both in 2-year stems and in recently formed vegetative organs as flower buds and immature fruits, which seem to suggest that it may be the same isolate, which has moved systemically inside the plant. The results presented here can play an important role in working out strategies for the effective and timely management of the disease and in reducing the number of unnecessary fungicide applications.

scholarly journals 150 Color Fading of Rose Petals Due to a Transient High Temperature Stress

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 415D-415
Author(s):  
M. Oren-Shamir ◽  
Dela Gal
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
Flower Color ◽  
High Temperature Stress ◽  
Anthocyanin Synthesis ◽  
Flower Buds ◽  
Total Anthocyanin ◽  
Stage Of Development ◽  
Red Color ◽  
Color Fading

Changes in temperature during rose flower development, often cause a significant fading of flower color, decreasing its market value. We are studying the effect of transient high temperature stress on red roses (Rosa ×hybrida, `Jaguar'). We have found that a transient temperature stress of 39/18 °C day/night respectively for 3 days, in comparison to the growth temperature of 26/18 °C, caused a significant fading to flower color at a mature bud stage. The plant organ responsible for color fading is the flower bud only. When the stress was applied to the whole plant, not including the flower buds, there was no change on the mature bud color. We have also shown that there are specific flower developmental stages sensitive to the transient increase in temperature. Flower buds at the critical stage of development, that have been exposed to temperature increase have a faded pink-red color when matured. Total anthocyanin levels of faded flowers, due to temperature stress, decreased to ≈50%. In addition, the ratio between the two anthocyanidins composing the red color, cyanidin and pelargonidin, changed dramatically due to the temperature stress: flowers on plants that have not overcome a temperature stress had a ration of 1:1, while those that have faded due to the temperature stress have a ration of 2:1 of pelargonidin to cyanidin, respectively. These findings hint to specific stages of anthocyanin synthesis, that are hypersensitive to increased temperature. We are now in the process of identifying and characterizing these stages.

scholarly journals Evaluation of Two Predictive Models for Forecasting Olive Leaf Spot in Northern Greece

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1200
Author(s):  
Thomas Thomidis ◽  
Konstantinos Michos ◽  
Fotis Chatzipapadopoulos ◽  
Amalia Tampaki
Keyword(s):  
Predictive Models ◽  
Leaf Spot ◽  
Conidial Germination ◽  
Polynomial Model ◽  
Leaf Wetness ◽  
Generic Model ◽  
Olive Leaf ◽  
Northern Greece ◽  
Disease Symptoms ◽  
Olive Trees

Olive leaf spot (Venturia oleaginea) is a very important disease in olive trees worldwide. The introduction of predictive models for forecasting the appearance of a disease can lead to improved disease management. One of the aims of this study was to investigate the effect of temperature and leaf wetness on conidial germination of local isolates of V. oleaginea. The results showed that a temperature range of 5 to 25 °C was appropriate for conidial germination, with 20 °C being the optimum. It was also found that at least 12 h of leaf wetness was required to start the germination of V. oleaginea conidia at the optimum temperature. The second aim of this study was to validate the above generic model and a polynomial model for forecasting olive leaf spot disease under the field conditions of Potidea Chalkidiki, Northern Greece. The results showed that both models correctly predicted infection periods. However, there were differences in the severity of the infection, as demonstrated by the goodness-of-fit for the data collected on leaves of olive trees in 2016, 2017 and 2018. Specifically, the generic model predicted lower severity, which fits well with the incidence of the disease symptoms on unsprayed trees. In contrast, the polynomial model predicted high severity levels of infection, but these did not fit well with the incidence of disease symptoms.

scholarly journals New contribution to the survey of the acrotony theory on the branch of one year grapevine: III - Role of buds and leaves in development, application in the vineyard of results obtained in laboratory and greenhouse

OENO One ◽  
2001 ◽  
Vol 35 (1) ◽  
pp. 1
Author(s):  
Béchir Ezzili ◽  
M. Bejaoui
Keyword(s):  
Second Phase ◽  
Second Stage ◽  
Apical Bud ◽  
Apical Buds ◽  
Stage Of Development ◽  
Cytokinin Treatment ◽  
Young Leaves ◽  
One Year ◽  
Development Application

<p style="text-align: justify;">The respective influences of the bud and leaves on stimulation of acrotony phenomenon was studied. Defoliation (all leaves at the stage budbursted + 30 days) and various bud ablation were made : buds 9, 10 ; 7, 8, 9, 10 ; 5, 6, 7, 8, 9, 10 ; 3, 4, 5, 6, 7, 8, 9, 10.</p><p style="text-align: justify;">Concerning the phenomen of acrotony, the role of apical bud and leaves developped on at 10 and 30 days after budburst were determined.</p><p style="text-align: justify;">The effect produced by excision of the apical buds shows that the two subadjacent buds were developped. All decapitation did not increase the percentage of budbreak.</p><p style="text-align: justify;">In all decapitations, the subadjacent buds were developped however, buds below were inhibed. The effect produced by excision of leaves in the second stage of development did not promote budbreak.</p><p style="text-align: justify;">On 10 bud canes, auxins synthesized in the developing young leaves seem to exercise their inhibiting effect on the budbreak of the subjacent buds.</p><p style="text-align: justify;">Cytokinins managed by the means of our operatory mode seem to reach the subjacents buds, modify the expression of the ramification of the canes with regard to the system usual acrotony and limit the inhibition basipetally. The budburst of the canes at a temperature of 18°C seems to be more important than that at 30°C day/ 20°night. Thus, the acrotony phenomenon decreases. When the apical branches are in second phase of growth, the size of the leaves become large. It seems that the leaves would exercise their inhibitions on the subjacent buds by the slant of the synthesized gibberillins and auxins. Cytokinins have no further role to play during this phase of growth and do not thwart anymore the inhibition. In the vineyard, the ANA treatment is totally inhibiting at 20 and 50 mg/l doses. In contrast, the 6BAP treatment at 20 mg/l shortly before budburst increases the budburst percentage for Muscatel of Italy.</p><p style="text-align: justify;">When the last treatment is performed during 25 days followed by a cytokinin treatment we notice budburst. The mechanism of these different growth regulators on the acrotony phenomenon has been discussed .</p>

scholarly journals Cold Injury of Southern Blueberries as a Function of Germplasm and Season of Flower Bud Development

HortScience ◽  
1991 ◽  
Vol 26 (1) ◽  
pp. 18-20 ◽  
Author(s):  
Kim Patten ◽  
Elizabeth Neuendorff ◽  
Gary Nimr ◽  
John R. Clark ◽  
Gina Fernandez
Keyword(s):  
Frost Damage ◽  
Vaccinium Corymbosum ◽  
Highbush Blueberry ◽  
Flower Buds ◽  
Flower Bud ◽  
Bud Development ◽  
Stage Of Development ◽  
Cold Damage ◽  
Southern Highbush ◽  
Flower Bud Development

The relative tolerance of flower buds and flowers of southern highbush blueberry (Vaccinium spp.) to cold damage was compared to rabbiteye (Vaccinium ashei Reade) and highbush blueberry (Vaccinium corymbosum L.). For similar stages of floral bud development, southern highbush and highbush cultivars had less winter freeze and spring frost damage than rabbiteye cultivars. Cold damage increased linearly with stage of flower bud development. Small fruit were more sensitive to frost damage than open flowers. Rabbiteye blueberry flower buds formed during the fall growth flush were more hardy than buds formed during the spring growth flush, regardless of cultivar or stage of development.

scholarly journals Tomato Leaf Development and Distribution as Influenced by Leaf Removal and Decapitation

HortScience ◽  
1990 ◽  
Vol 25 (6) ◽  
pp. 681-684 ◽  
Author(s):  
Dennis R. Decoteau
Keyword(s):  
Leaf Development ◽  
Cultural Practices ◽  
Fruit Production ◽  
Tomato Leaf ◽  
Leaf Removal ◽  
Tomato Plants ◽  
Canopy Development ◽  
Apical Bud ◽  
Apical Buds ◽  
Axillary Leaf

The influence of leaf removal and decapitation (removal of apical bud and top two nodes) of determinate tomato (Lycopersicon esculentum Mill cv. Mountain Pride) plants on canopy development was investigated. Leaf removal and decapitation influenced subsequent leaf development and distribution, and early fruiting of greenhouse-grown tomato plants. `Removal of young axillary leaves increased the size of main (true) leaves in the middle and upper nodes, increased the number of nodes, and increased the number of early fruit produced. Removal of main leaves reduced axillary leaf development at nodes 5 and 9. Decapitation increased axillary leaf development in the middle and upper nodes and delayed early fruit production. These results suggest that cultural practices of tomatoes that remove leaves or apical buds to influence fruiting also affect canopy leaf development and distribution.

scholarly journals Crop Injury from Sublethal Rates of Herbicide. I. Tomato

HortScience ◽  
2001 ◽  
Vol 36 (4) ◽  
pp. 669-673 ◽  
Author(s):  
James P. Gilreath ◽  
Carlene A. Chase ◽  
Salvadore J. Locascio
Keyword(s):  
Lycopersicon Esculentum ◽  
Fruit Set ◽  
Yield Losses ◽  
Foliar Injury ◽  
Flower Buds ◽  
Nontarget Organisms ◽  
Fruit Number ◽  
Stage Of Development ◽  
Better Than ◽  
Herbicide Glyphosate

Drift from pesticides can kill or damage nontarget organisms. In these studies, the effects of sublethal rates of the herbicide glyphosate applied prebloom, at bloom, and postbloom of the first flower cluster were evaluated in tomato (Lycopersicon esculentum Mill.). As rates increased from 1 to 100 g·ha-1, foliar injury and flower and fruit number per plant varied with the stage of development at the time of exposure and the time of evaluation after treatment. Plants treated with 60 and 100 g·ha-1 glyphosate prebloom and at bloom had developed moderate to severe foliar injury by 14 days after treatment, but phytotoxicity to plants treated postbloom was only mild to moderate. Blooms abscised from plants treated with 60 and 100 g·ha-1 glyphosate for several weeks after application and fruit set was reduced. Greatest yield losses occurred following treatment prebloom (just prior to bloom) and at bloom. Plants treated before emergence of flower buds, and more mature plants exposed when first cluster fruit were sizing, yielded better than did those treated just prior to bloom and at bloom. Chemical name used: N-(phosphonomethyl)glycine (glyphosate).

Intercrop of olive trees with cereals and legumes in Chalkidiki, Northern Greece

2021 ◽  
Author(s):  
K. Mantzanas ◽  
A. Pantera ◽  
D. Koutsoulis ◽  
A. Papadopoulos ◽  
D. Kapsalis ◽  
...  
Keyword(s):  
Northern Greece ◽  
Olive Trees
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