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A qPCR‐based method for detecting parasitism of Fopius arisanus (Sonan) in oriental fruit flies, Bactrocera dorsalis (Hendel)

Liang, Guang Hong, Jang, Eric B, Heller, Wade P, Chang, Chiou Ling, Chen, Jia Hua, Zhang, Fei Ping, Geib, Scott M
Pest management science 2015 v.71 no.12 pp. 1666-1674
Bactrocera dorsalis, Ceratitis capitata, DNA, Fopius arisanus, biological control, developmental stages, eggs, fruit flies, hosts, mass rearing, parasitism, parasitoids, pest management, population, quantitative polymerase chain reaction, rapid methods, species identification, United States
BACKGROUND: Parasitism detection and species identification are necessary in fruit fly biological control. Currently, release of mass‐reared Fopius arisanus is practiced worldwide, as it is effective in controlling Bactrocera dorsalis and Ceratitis capitata. To detect and assess parasitism in parasitoid mass‐rearing colonies and parasitism levels in field populations across all life stages of hosts, the development of a rapid, specific and sensitive method is important. RESULTS: A species‐specific probe was designed for F. arisanus, as well as a universal tephritid probe. Utilizing rapid DNA extraction techniques coupled with quantitative‐PCR, a simple and fast assay has been developed to detect parasitism of F. arisanus that is sensitive enough to detect the parasitoid across all developmental stages, including a single egg per host egg or 0.25 ng of parasitoid DNA in 40 ng of host DNA. The qPCR methods also detect a higher parasitism rate when compared with rearing‐based methods where parasitism rate is based on wasp emergence and where unemerged wasps are not included. CONCLUSION: This method is a rapid, sensitive and specific technique to determine the parasitism rate of F. arisanus across all life stages of B. dorsalis, which will be useful to predict parasitoid output from mass rearing and evaluate the outcome of pest suppression after mass release in the field. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.