Abstract

GONZALEZ-CABRERA, Jaime; ARREDONDO-BERNAL, Hugo C.  and  STOUTHAMER, Richard. Multiplex PCR assay to identify Trichogramma parasitoids (Hymenoptera, trichogrammatidae) reared from mexican insectaries. Agrociencia [online]. 2014, vol.48, n.7, pp.703-711. ISSN 2521-9766.

Accurate identification of species as biological candidates is the first step in establishing successful biological control programs. In Mexico, Trichogramma parasitoids are identified using morphological characters, which is a laborious procedure made only by experts; in addition, some morphological structures are susceptible to changes due to differences in diet or environment, and consequently there is a latent risk of misidentification. Moreover, morphological identification requires the presence of males, leaving female-only populations unidentifiable. As an alternative to morphological identification, the purpose of this work was to develop a molecular method for the identification of Trichogramma parasitoids from Mexican insectaries. Trichogramma species reared in six insectaries were DNA-identified and subsequently, based on differences in ITS2 sequences, a DNA-multiplex PCR assay was designed to distinguish among those reared species. Thus, discrepancies were found between the reported and DNA-determined species identity, whereas the sample of all the insectaries together was supposed to contain three species of Trichogramma (T. pretiosum, T. exiguum and T. platneri), only two species (T. pretiosum and T. fUentesi) were present. In addition, it was found the presence of unnoticed species replacement. Fortunately, an accurate taxonomic identification of Trichogramma species can be made by using the DNA-multiplex PCR assay that was generated in this work. Additionally, this methodology may identify the native Trichogramma species, whose use in mass rearing projects is uncommon.

Keywords : Trichogramma pretiosum; T. exiguum; T platneri; T. fuentesi; DNA-identification; ITS2 sequences.

        · abstract in Spanish     · text in English     · English ( pdf )