Program Item Details
TITLE: Susan Entz, Masters Student, Environmental Sciences, University of Lethbridge
SUBJECT: #184 Fungus That Kills Grasshoppers
SYNOPSIS: ..
AUDIO: Download Audio (mp3 format)
TRANSCRIPT:
#184 December 6, 2005
Interview starts at 11:50
Intro: Dr. Dan Johnson is one of Canada’s foremost experts on grasshoppers. And several of his graduate students at the University of Lethbridge are looking for more natural means to control outbreaks of these insects. One is Susan Entz. Her master’s work has focused a fungus used in other parts of the world. And as a result of her research she has developed a new test to detect it.
Susan Entz
SE: This fungus falls in the genus Metarhizium and it has been commercialized globally for biological control of grasshoppers in Australia and in Africa.
CC: WHERE WAS THIS FUNGUS ORIGINALLY DISCOVERED?
SE: Oh, that’s a good question because this genus is quite complex. It consists of a wide variety of what you might call siblings and most of them have them specific hosts. So when you talk about where it originated, well we’ve got so many different varieties within this genus it is quite difficult to determine.
CC: HOW DOES IT ACTUALLY WORK ON THE GRASSHOPPERS?
SE: The way it infects grasshoppers is that a spore will land on the grasshopper cuticle and it will penetrate the cuticle by a combination of enzymatic and mechanical means. Once it’s within the grasshopper, and providing it overcomes the grasshopper host’s defences, it will then replicate itself within the grasshopper. Eventually the grasshopper will die and the fungus will produce hyphae which then penetrate the grasshopper and it reenters the environment where it produces more spores, and the whole cycle begins again.
CC: SO FOR YOUR RESEARCH WHAT YOU’VE BEEN LOOKING AT IS WHETHER OR NOT WE CAN USE THIS IN CNADA?
SE: Yes, what we wanted to do was devise a molecular means of tracing this in the environment and that was the primary research focus of my thecis.
CC: SO WHAT DID YOU DO?
SE: I basically devised a molecular assay that would specifically detect the fungus in question.
CC: AND HOW DOES THAT WORK?
SE: It recognizes a certain nucleatide sequence within the genome of the fungus and that nucleatide sequence is specific to that fungus. So if we find it, we can be relatively assured it does belongs to that particular organism.
CC: HOW DO YOU ACTUALLY TEST FOR THAT?
SE: What we do is we extract the DNA either from the fungus itself in pure culture or from infected grasshoppers that have been exposed to that particular fungus. And once the DNA is extracted, we run it through a test known as a polymerized chain reaction assay, which is also known as PCR. It’s very common. And through a series of amplifications of the specific sequence in question, we end up with a visible product when we analyze it later.
CC: IS THERE ANY INDICATION AT THIS POINT THAT THE INTRODUCTION OF THIS FUNGUS WOULD CAUSE ANY ENVIROMENTAL PROBLEMS HERE IN CANADA?
SE: Probably not because extensive safety testing has been conducted on this organism. We have looked at impact on non-target organisms. For example, Dan and his colleagues have determined that application is safe to ring-necked pheasants in Canada. But it has also shown to be safe to aquatic organisms and other insects that interact with grasshoppers in the natural ecosystem.
CC: THIS PARTICULAR FUNGUS IS COMING FROM OUTSIDE THE COUNTRY BUT DID YOU FIND, DO WE HAVE ANYTHING LIKE IT THAT’S HERE NATURALLY.?
SE: Well in a soil survey I conducted after we developed the assay, we did find a few related isolates of metarulizium that were very similar to the commercial isolate we were thinking of using. And in later bio-assays, we did find that we had one isolate that showed a degree of infection in grasshoppers that was comparable to commercial isolate.
CC: SO IS THAT SOMETHING THAT WE COULD LOOK AT COMMERCIALIZING HERE?
SE: It is a possibility but we have a lot more work to do. For example, because this isolate was obtained from soil, we really don’t know what the host target or range is. So that would have to be determined prior to any application of this fungus.
CC: WHAT’S THE NEXT STEP. NOW THAT YOU’VE DONE THAT ASSAY, WHAT HAPPENS NOW?
SE: What happens now if we’re trying to find an industry partner who is interested in collaborating with us in terms of more work to evaluate how safe our native fungus would be and what its potential impact would be on non-target organisms.
CC: AND AS FAR AS THE FUNGUS THAT’S ALREADY BEEN COMMERCIALIZED, IS IT SOMETHING WE’LL SEE BEING USED IN CANADA SOON, OR IS THERE STILL MORE WORK TO BE DONE ON THAT ONE?
SE: Well we probably won’t see it soon because it is considered an exotic organism, so there’s certainly some degree of concern over the introduction of exotics for biological control.
CC: IT SEEMS LIKE THERE’S AN AWFUL LOT OF RESEARCH GOING ON IN THIS WHOLE AREA OF BIOLOGICAL CONTROL. WHAT ELSE IS HAPPENING?
SE: In terms of molecular monitoring, it’s still very early in the science in this area, so there will of course be more research done. But we hope to eventually apply it.
CC: SO WHY SHOULD BE GO THE BIOLOGICAL ROUTE? WHY NOT JUST NUKE THESE THINGS WITH ALL THE CHEMICALS THAT WE HAVE OUT THERE ALREADY?
SE: Well for one thing, chemicals are not target specific. They tend to act upon a lot of non-target organism. There are also environmental and health concerns involved with the use of chemical pesticides
CC: HAS YOUR WORK BEEN PUBLISHED?
SE: Yes it has. It’s titled “Development of a PCR-based diagnostic assay for the specific detection of the entomomopathogenic fungus Metarhizium anisopliae var. acridium“ It’s been published in the Journal Microbiological Research. And you can get a copy by contract DanJohnson at Dan.Johnson@uleth.ca
CC: THANK YOU VERY MUCH SUSAN .
SE: Thank you.
Susan Entz is a masters student in environmental sciences at the University of Lethbridge. Her supervisor is Dr. Dan Johnson, Canada Research Chair in Sustainable Grassland Ecosystems.
FEATURED LINK: University of Lethbridge