Molecular Assay For The Detection Of A Fungus Proposed For Grasshopper Control

S. C. Entz¹*, D. L. Johnson¹ and L. M.Kawchuk ²

Metarhizium anisopliae var. acridum is a fungus that is pathogenic to acridids (grasshoppers and locusts). M. anisopliae var. acridum is indigenous to the tropics. Isolates have been registered in Africa (Green Muscle®, 1999) and Australia (Green Guard®, 2000). Related strains occur naturally in soil. M. anisopliae var. acridum is a potential alternative to chemical insecticides for grasshopper control in Canada. Before an organism can be registered as a pesticide, it must be shown to be safe for non-target organisms, and capable of being monitored in the environment. Traditionally, identification of M. anisopliae var. acridum infection in grasshoppers and locusts has relied upon development of fungal growth in infected cadavers. Conventional methods of detection have been based on culture and bioassay. We developed a molecular-based method for the detection of M. anisopliae var. acridum. Sequence data from the distinct internal transcribed spacer (ITS) rDNA regions facilitated the design of PCR primers that were used in PCR-based diagnostic assays for the detection of fungal DNA. The amplified sequence was 420 bp in length and specific to M. anisopliae var. acridum. Native isolates of related fungi (M. aniospliae var. anisopliae and M. flavoviride var. flavoviride) produced no PCR product with these primers. This test did not produce false positives when tested with other fungal entomopathogens, plant pathogens, mycopathogens, and soil saprophytes. The assay was also effective for the detection of M. anisopliae var. acridum DNA in infected grasshoppers.


Source
2nd OACC Organic Research Workshop, Presented in association with the Organic Connections: Prairie Wide Organic Conference and Trade Show, November 14-16th, 2004


Author Locations and Affiliations
(1) University of Lethbridge, Lethbridge, AB,
(2) Agriculture and Agri-Food Canada, Lethbridge,AB
* Corresponding author: susan.entz@uleth.ca