Polymorphism in Euphyllura olivina (Costa, 1839) (Hemiptera: Aphalaridae) in Olive Groves in Algeria

The olive psyllid Euphyllura olivina Costa (Homoptera, Psyllidae) causes considerable damage in olive groves in the Mediterranean basin, there by affecting production. To assess the rate of infestation and provide elements of integrated pest management, we monitored the life cycle and bio–ecology of this pest through population counts on the leaves and twigs of the tree from 29 March 2019 to 27 March 2020 at two relatively distant olive farms (Ain fares and Oued taria) in the wilaya of Mascara, Algeria. Our results showed that infestation was high on trees in the Oued taria farm. We found that E. olivina developed two generations per year, in spring, influenced by the climatic factors. The difference between the relative abundance of the different life stages (eggs, larval instar 1, 2, 3, 4 and 5, female and male) in the cardinals orientations was significant. Infestation was highest on the southern and central orientations of the tree. Populations fluctuations were significantly affected by season at both farms.

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Diversity of insects associated with olive (Oleaceae) groves across a dryland climate gradient in Algeria

The Canadian Entomologist ◽

10.4039/tce.2019.35 ◽

2019 ◽

Vol 151 (5) ◽

pp. 629-647 ◽

Cited By ~ 3

Author(s):

Smail Chafaa ◽

Fateh Mimeche ◽

Haroun Chenchouni

Keyword(s):

Species Richness ◽

Linear Models ◽

Permutation Test ◽

Arid Climate ◽

Functional Feeding Groups ◽

Insect Diversity ◽

Insect Communities ◽

Correlation Matrices ◽

Euphyllura Olivina ◽

Olive Groves

AbstractThis study investigated insect diversity of olive (Olea europaea Linnaeus (Oleaceae)) groves grown in arid and semiarid climates in northeastern Algeria. Using several sampling techniques, a total of 1326 insect specimens were collected and identified into 151 species, 124 genera, 65 families, and 10 orders. Hymenoptera and Coleoptera were quantitatively the most abundant, whereas the dominant functional feeding groups were phytophages then predators. The entomofauna included several olive pests such as Bactrocera oleae (Rossi) (Diptera: Tephritidae), Parlatoria oleae (Colvée) (Hemiptera: Diaspididae), Euphyllura olivina (Costa) (Hemiptera: Liviidae), and Liothrips oleae Costa (Thysanoptera: Phlaeothripidae). Although insect diversity parameters recorded for both observed and expected species richness were higher in olive groves grown under semiarid compared with arid climate, the completeness rate of species richness obtained using the nonparametric incidence estimators was higher in arid olive groves. Generalised linear models showed that the number of individuals and species richness varied significantly between climates (P < 0.01), whereas the variation of the rest of diversity parameters was not significant. Diversity traits of insect assemblage of each climatic region were positively correlated. Besides, the Mantel permutation test revealed similar patterns (r = 0.91, P < 0.0001) between correlation matrices of the two climates. When increasing the number of samples, species richness extrapolation revealed that diversity is expected to increase by 130% in olive groves grown under arid climate and 93% in semiarid climate. These increases are related to continuous appearance of rare and scarce insects as demonstrated by species rarefaction curves. Even with high evenness values of insect communities, similarity was low between climate indicating the rarity and scarcity of populations.

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Semi-Automatic Method for Early Detection of Xylella fastidiosa in Olive Trees Using UAV Multispectral Imagery and Geostatistical-Discriminant Analysis

Remote Sensing ◽

10.3390/rs13010014 ◽

2020 ◽

Vol 13 (1) ◽

pp. 14

Author(s):

Annamaria Castrignanò ◽

Antonella Belmonte ◽

Ilaria Antelmi ◽

Ruggiero Quarto ◽

Francesco Quarto ◽

...

Keyword(s):

Discriminant Analysis ◽

Early Detection ◽

Plant Pathogens ◽

Early Stage ◽

Xylella Fastidiosa ◽

Mediterranean Countries ◽

Parametric Classification ◽

Aerial Vehicle ◽

Olive Groves ◽

Olive Trees

Xylella fastidiosa subsp. pauca (Xfp) is one of the most dangerous plant pathogens in the world. Identified in 2013 in olive trees in south–eastern Italy, it is spreading to the Mediterranean countries. The bacterium is transmitted by insects that feed on sap, and causes rapid wilting in olive trees. The paper explores the use of Unmanned Aerial Vehicle (UAV) in combination with a multispectral radiometer for early detection of infection. The study was carried out in three olive groves in the Apulia region (Italy) and involved four drone flights from 2017 to 2019. To classify Xfp severity level in olive trees at an early stage, a combined method of geostatistics and discriminant analysis was implemented. The results of cross-validation for the non-parametric classification method were of overall accuracy = 0.69, mean error rate = 0.31, and for the early detection class of accuracy 0.77 and misclassification probability 0.23. The results are promising and encourage the application of UAV technology for the early detection of Xfp infection.

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Environmental challenges of the intensive woody crops: The case of super high-density olive groves

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.149212 ◽

2021 ◽

pp. 149212

Author(s):

José Guerrero-Casado ◽

Antonio J. Carpio ◽

Francisco S. Tortosa ◽

Anastasio J. Villanueva

Keyword(s):

High Density ◽

Environmental Challenges ◽

Woody Crops ◽

Olive Groves

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Further In Vitro Assessment and Mid-Term Evaluation of Control Strategy of Xylella fastidiosa subsp. pauca in Olive Groves of Salento (Apulia, Italy)

Pathogens ◽

10.3390/pathogens10010085 ◽

2021 ◽

Vol 10 (1) ◽

pp. 85

Author(s):

Giuseppe Tatulli ◽

Vanessa Modesti ◽

Nicoletta Pucci ◽

Valeria Scala ◽

Alessia L’Aurora ◽

...

Keyword(s):

Control Strategy ◽

Xylella Fastidiosa ◽

In Planta ◽

Bacterial Concentration ◽

Infected Area ◽

Olive Groves ◽

Term Evaluation ◽

In Vitro Assessment ◽

Olive Trees

During recent years; Xylella fastidiosa subsp. pauca (Xfp) has spread in Salento causing relevant damage to the olive groves. Measures to contain the spreading of the pathogen include the monitoring of the areas bordering the so-called “infected” zone and the tree eradication in case of positive detection. In order to provide a control strategy aimed to maintain the tree productivity in the infected areas, we further evaluated the in vitro and in planta mid-term effectiveness of a zinc-copper-citric acid biocomplex. The compound showed an in vitro bactericidal activity and inhibited the biofilm formation in representative strains of X. fastidiosa subspecies, including Xfp isolated in Apulia from olive trees. The field mid-term evaluation of the control strategy assessed by quantitative real-time PCR in 41 trees of two olive groves of the “infected” area revealed a low concentration of Xfp over the seasons upon the regular spraying of the biocomplex over 3 or 4 consecutive years. In particular, the bacterial concentration lowered in July and October with respect to March, after six consecutive treatments. The trend was not affected by the cultivar and it was similar either in the Xfp-sensitive cultivars Ogliarola salentina and Cellina di Nardò or in the Xfp-resistant Leccino. Moreover, the scoring of the number of wilted twigs over the seasons confirmed the trend. The efficacy of the treatment in the management of olive groves subjected to a high pathogen pressure is highlighted by the yielded a good oil production

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