The effect of MicroRNAs on the insecticide resistance mechanism in populations of the pistachio psyllid Agonoscena pistaciae, a pest of pistachios

Abstract

The pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), is a major pest of pistachio orchards in Türkiye, particularly in regions with intensive pistachio cultivation. Despite repeated pesticide applications, psyllid population density and the associated damage continue to persist in many orchards. This situation suggests the possible development of resistance to commonly used pesticides. In this study, resistance to the most widely used pesticide active ingredient in the region, spirotetramat, was investigated at both phenotypic and molecular levels. Psyllid populations were collected from pistachio orchards with a documented history of pesticide application and from orchards with no prior pesticide use. Under laboratory conditions, psyllids were reared on pistachio seedlings, and bioassays were conducted using six concentrations of spirotetramat (0, 25, 50, 75, 100, and 150 mg/L). Dose-dependent increases in mortality were observed, with the highest mortality recorded at the highest concentration. Mortality rates were consistently higher in psyllid populations collected from unsprayed orchards compared to those from sprayed orchards. LC50 and LC90 values were notably higher in populations from previously sprayed locations, indicating reduced susceptibility to spirotetramat. Molecular analyses were performed on surviving nymphs following bioassays. Expression levels of the CYP307a1 gene were lower than those of mir-2b-3p, mir-14b-5p, and mir-2756-5p in populations from unsprayed orchards. In contrast, CYP9f2 and the miRNAs mir-2b-3p, mir-14b-5p, mir-316-5p, and mir-2756-5p exhibited variable expression patterns across all populations. These findings suggest that miRNAs and P450 genes may play a role in the molecular mechanisms underlying spirotetramat resistance in A. pistaciae populations. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2026.