Species-specific multiplex PCR for the rapid diagnosis of egg parasitoids of light brown apple moth, Epiphyas postvittana, in northern California

ABSTRACT

The light brown apple moth (LBAM) was first detected in Alameda County, California, USA, in fall of 2006, triggering a major government response aimed at containment and eradication. The augmentative release of resident egg parasitoids was highlighted among several control methods to prevent the spread of LBAM in California. Egg parasitoids in the genus Trichogramma are utilised worldwide for the control of lepidopteran pests, including the control of LBAM in Australia. Surveys of the resident egg parasitoids attacking LBAM in California, carried out in 2009, resulted in the identification of five Trichogramma species: T. fasciatum, T. platneri, T. deion, T. nr pretiosum, and T. fuentesi. Of these, only T. platneri had previously been recorded in our study area. These initial identifications were based on ribosomal DNA sequences. To facilitate further monitoring of the distribution and abundance of these species, a species-specific multiplex-PCR (ssmPCR) was developed to allow rapid and affordable identification. To save further time and expense, we took away the traditional DNA extraction step and demonstrated that the method performs well when an intact wasp is placed directly into the amplification reaction. In all, per specimen identification is estimated to cost significantly less than one US dollar.

KEYWORDS:

• Trichogramma
• ITS2
• direct PCR
• augmentative biological control

Acknowledgements

Our thanks goes to Xin-Geng Wang for the submission of Trichogramma specimens from Alameda for species confirmation.

Disclosure statement

No potential conflict of interest was reported by the author(s).