Nowadays, olive orchards in the Mediterranean are threatened by the olive quick decline syndrome, caused by the insect-borne bacteria Xylella fastidiosa. This phytosanitary emergency has called for the implementation of environmentally friendly and sustainable control strategies to prevent X. fastidiosa spread. In response to this concern, entomopathogenic fungi (EF) stand out as efficient biological control agents that infect the insects by contact. In addition, EF have been recently reported as endophytes that systemically protect the crop against sap-sucking pests, alter their probing and feeding behaviour and protect the plant against phytopathogenic microorganisms and plant viruses. In this work, activity of EF strains against nymphs and adults of Philaenus spumarius L. (Hemiptera: Aphrophoridae), the main vector of X. fastidiosa in all the European outbreaks, was assayed with the objective of reducing X. fastidiosa transmission. In the first experiment against nymphs, alfalfa plants were sprayed with Beauveria bassiana (Balsamo) Vuillemin and Metarhizium brunneum Petch conidial suspensions, resulting in 51.8 and 50.0% nymphal mortality, respectively. In the experiment against adults, individuals of P. spumarius were allowed to acquire X. fastidiosa and were used to inoculate EF sprayed periwinkle plants. The epiphytic and endophytic fungal effect on the periwinkle plants caused the mortality of 31.0 and 40.0% of P. spumarius adults when the selected B. bassiana and M. brunneum strains were assayed. Besides that, preliminary results showed that X. fastidiosa transmission rate was lower when the receptor plants had previously been treated with B. bassiana conidial suspension (65.0%) compared to that observed in the control plants (85.0%). However, no differences in the X. fastidiosa transmission rate were discerned between M. brunneum-treated plants (100.0%) and control (93.3%) plants. Such effects of the EF on the insect vectors and plant host may have direct consequences on the epidemiology of X. fastidiosa-related diseases.
Direct and indirect interference of Xylella fastidiosa vector transmission using endophytic entomopathogenic fungi
CAVALIERI V;SAPONARI M;BODINO N;
2022
Abstract
Nowadays, olive orchards in the Mediterranean are threatened by the olive quick decline syndrome, caused by the insect-borne bacteria Xylella fastidiosa. This phytosanitary emergency has called for the implementation of environmentally friendly and sustainable control strategies to prevent X. fastidiosa spread. In response to this concern, entomopathogenic fungi (EF) stand out as efficient biological control agents that infect the insects by contact. In addition, EF have been recently reported as endophytes that systemically protect the crop against sap-sucking pests, alter their probing and feeding behaviour and protect the plant against phytopathogenic microorganisms and plant viruses. In this work, activity of EF strains against nymphs and adults of Philaenus spumarius L. (Hemiptera: Aphrophoridae), the main vector of X. fastidiosa in all the European outbreaks, was assayed with the objective of reducing X. fastidiosa transmission. In the first experiment against nymphs, alfalfa plants were sprayed with Beauveria bassiana (Balsamo) Vuillemin and Metarhizium brunneum Petch conidial suspensions, resulting in 51.8 and 50.0% nymphal mortality, respectively. In the experiment against adults, individuals of P. spumarius were allowed to acquire X. fastidiosa and were used to inoculate EF sprayed periwinkle plants. The epiphytic and endophytic fungal effect on the periwinkle plants caused the mortality of 31.0 and 40.0% of P. spumarius adults when the selected B. bassiana and M. brunneum strains were assayed. Besides that, preliminary results showed that X. fastidiosa transmission rate was lower when the receptor plants had previously been treated with B. bassiana conidial suspension (65.0%) compared to that observed in the control plants (85.0%). However, no differences in the X. fastidiosa transmission rate were discerned between M. brunneum-treated plants (100.0%) and control (93.3%) plants. Such effects of the EF on the insect vectors and plant host may have direct consequences on the epidemiology of X. fastidiosa-related diseases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
