U of A professor discovers biological control of slugs

Slug control may soon become easier – thanks to nematode parasites.

Originally trained in entomology, Luong Link, Associate Professor at the University of Alberta, is the principal investigator of a study examining facultative parasitism and its applications as biological pest control.

A optional parasite is a parasite that can be a free-living organism – an organism that does not directly depend on other organisms for its survival – but which, under certain conditions, changes to a parasitic lifestyle.

“One of [facultative parasitic] systems I ran into was a nematode parasite that infects slugs, ”Luong said.

Luong’s slug research began in 2018 when a researcher from the UK contacted the Department of Biological Sciences at the University of Alberta to ask if anyone was interested in collaborating on a slug project. .

“We started doing a slug survey in central and northern Alberta to see what kind of pests they have,” Luong said. “In 2019, my students and I collected over 2,000 slugs. We checked them all for parasites and, voila, we found the nematode parasite. “

The nematode in question originated from genus Phasmarhabditis. According to Luong, a similar species of this nematode is available in the UK, Europe and other parts of the world, but has yet to be marketed as a pest control product in Canada.

This 2019 discovery of the nematode in slugs leads Luong to believe that nematode parasites may soon be a form of biological pest control in Canada.

“Now that we have been able to identify [the nematode] in Alberta it would no longer be considered invasive, ”she said. “Before we can introduce it in the field as a biological control agent, we need to do experiments to assess the safety and efficacy of this nematode. We isolated the nematode, cultivated it in our lab, and continued to collect slugs for research.

Luong and his team are currently picking up slugs within a two hour radius of Edmonton. Luong’s end goal is to identify as many different habitats as possible in Alberta and gain a better understanding of the distribution of slugs and associated nematodes in agricultural fields.

“Slugs are considered a pest in home gardens and agricultural environments,” Luong said. “In 2019, we widely surveyed allotment gardens. This year we really focused our data on nurseries and greenhouses and started to study agricultural fields like wheat, corn, [and] canola. At the same time, we will carry out laboratory experiments to better determine the biology, infectivity and effectiveness of this nematode as a biological control agent.

Ultimately, Luong would like his lab’s research to focus on answering questions about how and when organisms changed from a free to a parasitic lifestyle using the slug nematode system.

“One hypothesis is that facultative parasites [serve] as an evolutionary springboard between free and parasitic lifestyles, ”Luong explained.

“A facultative parasite is a very enticing possibility because they live on the fringes between the two worlds. They can live freely, but when they run out of food or conditions become unfavorable in the environment, then they can parasitize a host and find a whole new source of nutrients. This makes it a very interesting study organization from a fundamental science point of view.