Development of DNA Melt Curve Analysis for the Identification of Lepidopteran Pests in Almonds and Pistachios
Department of Plant Science, California State University, Fresno, 2415 E. San Ramon Ave, Fresno, CA 93740-8033, USA
Department of Environmental Science, Policy, & Management, University of California Berkeley, Berkeley, CA 94720-3114, USA
Author to whom correspondence should be addressed.
Current address: Department of Soil and Crop Science, 2474 Texas A&M University, College Station, TX 77843, USA.
Academic Editor: Lukasz L. Stelinski
Received: 11 May 2021 / Revised: 4 June 2021 / Accepted: 9 June 2021 / Published: 15 June 2021
Almonds and pistachios are fed upon by a diverse assemblage of lepidopteran insects, several of which are economically important pests. Unfortunately, identification of these pests can be difficult, as specimens are frequently damaged during collection, occur in traps with non-target species, and are morphologically similar up to their third instar. Here, we present a quantitative PCR based melt curve analysis for simple, rapid, and accurate identification of six lepidopteran pests of almonds and pistachios: navel orangeworm, peach twig borer, oriental fruit moth, obliquebanded leafroller, raisin moth, and Indian meal moth. We demonstrate that the dissociation or the “melt” temperature(s) of a 658 bp section of cytochrome c oxidase subunit 1 provides unambiguous species level identification of these six species and is reproducible in field specimens collected following conventional orchard practices. The melt curve’s simplicity allows it to be performed in any basic molecular biology laboratory with a quantitative PCR.