Addressing the problem of sulphur cinquefoil in Canada

Overview

Results

The team

Related information

So what's the problem?

Sulphur cinquefoil (Potentilla recta), is a long-lived perennial native to Eurasia. It was introduced to North America over a hundred years ago. Since then, it has invaded disturbed habitats, such as roadsides and pastureland and also semi-natural habitats such as open forests. It is able to hybridize with North American cinquefoil species or to displace native plants. There is also a concern that this weed may become a vector for pests of economically important plant species.

What is this project doing?

A biological control project was started in 1992, but due to both the uncertainty of finding a host-specific biological control agent and the funding situation, the project came to a premature end in 2002. However, following an expression of interest by the British Columbia Ministry of Forests, Lands and Natural Resource Operations, Canada, a smaller-scale project for the biological control of sulphur cinquefoil was revived in 2008.

Results so far

To start with, we summarized the available data from previous research for the period 1992-2002. The root-mining clear-wing moth Tinthia myrmosaeformis and the flower-bud attacking weevil Anthonomus rubripes were studied in depth, but specificity was not satisfactory. Preliminary work had been conducted for three newly prioritized potential biological control agents: two cynipid gall wasps, Diastrophus sp. near mayri from Turkey and D. mayri from Ukraine, and an unidentified gall midge from western Turkey. Work on these three species was re-started in 2008.

In tests conducted in 2008 and 2009, mainly with D. mayri from Ukraine and to a lesser extent with Diastrophus sp. near mayri, no galls were induced on P. recta. In 2011, further attempts to elicit gall induction by Diastrophus sp. near mayri were not successful and work was discontinued with these species.

A gall midge collected in Turkey by Dr Ferit Turanli (from Ege University, Izmir, Turkey) in 2000 and 2001 was described in 2011 by Dr Marcela Skuhravá, (from the Czech Republic) as Janetiella potentillogemmae, a species new to science. Preliminary studies showed that it is able to develop on the North American P. recta. Females oviposit into the meristematic tissue (growing point) of side buds on the main shoots, inhibiting the growth of side shoots.
During a field trip to Turkey in 2011, 235 galls of J. potentillogemmae were collected and overwintered at CABI in Delémont, Switzerland. Adults emerged between 16 April and 11 May. While no mating was observed, eggs were found on cut shoots and females were subsequently offered potted plants in no-choice tests (exposing one plant to the adults). P. recta of five different origins, one European and five North American native Potentilla species were exposed. Eggs were found on some of the P. recta from Turkey, unfortunately, no galls developed.

After discussion with our sponsors and collaborators in Canada, it was finally decided to stop the Potentilla project. A wrap up publication will be prepared summarizing work on the project and lessons to be learned from the study.

Project Executive