U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

A HRM Assay for Rapid Identification of Members of the Seedcorn Maggot Complex (Delia florilega and D. platura) (Diptera: Anthomyiidae) and Evidence of Variation in Temporal Patterns of Larval Occurrence

Hervé Van der Heyden, Anne-Marie Fortier, Jade Savage
Journal of economic entomology 2020 v.113 no.6 pp. 2920-2930
DNA, Delia florilega, Delia platura, crop damage, cryptic species, data collection, entomology, integrated pest management, larvae, mitochondrial genes, phenology, surveys, Quebec
The seedcorn maggot Delia platura (Meigen), and the bean seed maggot Delia florilega (Zetterstedt) can cause considerable feeding damage to a wide range of cultivated crops. The recent discovery of two distinct genetic lines of D. platura, each with a unique distribution pattern overlapping only in eastern Canada, suggests the presence of a new cryptic species for the group. The reliable identification of the three species/lines in the seedcorn maggot complex is crucial to our understanding of their distribution, phenology, and respective contribution to crop damage as well as to the development of specific integrated pest management approaches. As these taxa are morphologically indistinguishable in the immature stages, we developed a high-resolution melting PCR (HRM) assay using primers amplifying a variable 96-bp PCR product in the CO1 mitochondrial gene for rapid and economical identification of specimens. The three species/lines exhibited distinguishable melting profiles based on their different Tₘ values (between 0.4 and 0.9°C) and identification results based on HRM and DNA sequencing were congruent for all specimens in the validation data set (n = 100). We then used the new, highly sensitive HRM assay to identify survey specimens from the seedcorn maggot complex collected in Quebec, Canada, between 2017 and 2019. Progress curves developed to document the temporal occurrence patterns of each species/lines indicate differences between taxa, with the N-line (BOLD:AAA3453) of D. platura appearing approximately 17 d before D. florilega (BOLD:ACR4394) and the H-line (BOLD:AAG2511) of D. platura.