Current Distribution of the Olive Psyllid, <i>Euphyllura olivina</i>, in California and Initial Evaluation of the Mediterranean Parasitoid <i>Psyllaephagus euphyllurae</i> as a Biological Control Candidate

• Main Authors: Evelyne Hougardy, Xingeng Wang, Brian N. Hogg, Marshall W. Johnson, Kent M. Daane, Charles H. Pickett
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Insects
• Subjects: olive psyllid; <i>euphyllura olivina</i>; <i>psyllaephagus euphyllurae</i>; california; distribution; foreign collections; classical biological control; non-target assessment
• Online Access: https://www.mdpi.com/2075-4450/11/3/146

The olive psyllid, <em>Euphyllura olivina</em>, is a newly invasive species to California with the potential to become an economical pest if it reaches the olive production regions of California&#8217;s Central Valley. Here, we report on surveys undertaken in California to assess the psyllid&#8217;s current distribution and the occurrence of parasitism. Additionally, we present results of foreign collections of its parasitoids and initial non-target studies of a possible biological control agent, the Mediterranean parasitoid <em>Psyllaephagus euphyllurae</em>. The current distribution of the psyllid appears to be limited to the California coast between Monterey and San Diego; there have been no reports of infestations on olives in the major production areas of central and northern California. <em>Psyllaephagus euphyllurae</em> was the major primary parasitoid found in our foreign collections. The potential non-target impact of <em>P. euphyllurae</em> was tested on three native North American psyllid species: <em>Neophyllura</em> <em>arctostaphyli</em>, <em>Euglyptoneura </em>nr.<em> robusta</em>, and <em>Calophya</em> <em>nigrella</em>. No <em>P. euphyllurae</em> developed on the non-target species during no-choice tests. Behavioral observations in choice tests confirmed no attack on the non-target hosts, although the parasitoid did remain longer on <em>N. </em><em>arctostaphyli</em>-infested manzanita plants, and revealed no host feeding behavior.