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Bactericidal and plant defense elicitation activities of Eucalyptus oil decrease the severity of infections by Xylella fastidiosa on almond plants

Authors: Laura Montesinos, Aina Baró, Beatriz Gascón and Emilio Montesinos*
Date Published: 15/03/2023
Via: https://doi.org/10.3389/fpls.2023.1122218


The activity of Eucalyptus essential oil against eleven strains pertaining to six species of plant pathogenic bacteria was studied using growth inhibition and contact assays. All strains were susceptible to the formulation EGL2, and Xylella fastidiosa subspecies and Xanthomonas fragariae were the most sensitive. The bactericidal effect was strong causing 4.5 to 6.0 log reductions in survival in 30 min at concentrations in the range of 0.75 to 15.0 μl/ml depending on the bacteria tested. Transmission electron microscopy of the formulation EGL2 against the three X. fastidiosa subspecies studied allowed the observation of a strong lytic effect on bacterial cells. In addition, the preventive spray application of EGL2 to potted pear plants subsequently inoculated with Erwinia amylovora significantly decreased the severity of infections. Almond plants treated by endotherapy or soil drenching, and then inoculated with X. fastidiosa showed a significant decrease in disease severity as well as in the levels of the pathogen, depending on the strategy used (endotherapy/soil drenching, preventive/curative). The treatment by endotherapy in almond plants induced the expression of several genes involved in plant defense. It was concluded that the reduction of infections by the Eucalyptus oil treatments was due to the combination of its bactericidal and plant defense induction activities.

Direct and indirect effects of two endophytic entomopathogenic fungi on survival and feeding behaviour of meadow spittlebug Philaenus spumarius

Authors: Meelad Yousef-Yousef, Marina Morente, Natalia González-Mas, Alberto Fereres, Enrique Quesada-Moraga, Aranzazu Moreno

Date: 01/11/23

Highlights: Direct exposure of Philaenus to Metarhizium brunneum reduces its survivorship. M. brunneum successfully colonises the host plant and reduces survival of Philaenus. Philaenus reaches the xylem faster on M. brunneum-colonised plants. Xylem sap ingestion by...

Functional Peptides for Plant Disease Control

Authors: Emilio Montesinos

Date: 02/06/23

Plant disease control requires novel approaches to mitigate the spread of and losses caused by current, emerging, and re-emerging diseases and to adapt plant protection to global climate change and the restrictions on the use of conventional pesticides. Currently,...

Detection of Xylella fastidiosa in Host Plants and Insect Vectors by Droplet Digital PCR

Authors: Nicola Bodino, Vincenzo Cavalieri, Crescenza Dongiovanni, Maria Saponari, and Domenico Bosco

Date: 21/03/23

Spatial-temporal dynamics of spittlebug populations, together with transmission biology, are of major importance to outline the disease epidemiology of Xylella fastidiosa (Xf) subsp. pauca in Apulian olive groves. The spread rate of Xf is...