Insect Can Be Effective Predator of Meadow Spittlebug Vector of Xylella

An entomologist found evidence that North American insect can be used to limit the presence of Meadows Spittlebugs vectors of the Xylella fastidiosa CoDiRO strain on olive trees.

Research conducted at the University of Bari Aldo Moro produced useful findings on the employment of the assassin bug Zelus renardii in tackling the onset of Philaenus spumarius, better known as the Meadow Spittlebug, which is the known vector of Xylella fastidosa pauca that causes the Olive Quick Decline Syndrome OQDS (or CoDiRO). 

“Every year, we introduce to our countries several new species of insects,” said the associate professor of general and applied entomology at the Department of Soil, Plant and Food Sciences of the Apulian university, Francesco Porcelli who conducted the study.

“In the case of adult Philaenus, since the earlier stages of the procedures for containment of Xylella, we could rely only on chemical treatments to be applied in a short period during the flowering of olive trees,” he explained. “Nowadays, our goal is to include an effectual biological control action in conventional and organic IPM that can integrate or replace chemical control with an organic one.”

Porcelli and his group of researchers (Francesca Garganesa, Roberta Roberto, Lina D’Accolti, Ugo Picciotti, Laura Diana, Valentina Russo, Martina Salerno, Francesco Diana, Riccardo Gammino, Angela Schiavarelli, Valdete Sefa, Ahmed El Kenawy, Daniele Cornara) met the Zelus, which is native to North America, five years ago in the context of their research on Macrohomotoma gladiata, an Asian Ficus pest recently introduced to Europe.

Having noted that Zelus was an active predator of this tropical insect, they bred it in a lab and tried to use it against other pests. During an experiment, in the framework of doctoral research on Aleurocanthus spiniferus and on Philaenus, they put an adult insect alongside some spittlebugs and “it was love at first sight,” Porcelli affirmed. “Zelus turned out to be fatal for adult Philaenus and now, after several tests, we are able to confirm the first evidence.” 

Now, the researchers should be able to breed the insect on a mass scale, in order to use it as living insecticide. According to their evaluations, a new balance between populations of the insects already exists since Zelus was found in Italy in 2012 and no major demographic explosions of this species occurred. “This means that the carrying capacity of the ecosystem with regard to Zelus population is modest,” the Apulian entomologist observed. More