1. Weeds and invasive plants
Katharina Dehnen-Schmutz

2. Biological invasions
• One out of five main direct drivers for biodiversity
changes globally
• Causing high costs for society
– $120 billion/annually in the US (Pimentel et al. 2005)
– €2.5 billion/year in the EU (Kettunen et a. 2009)
– £1.7 billion/year in the UK (CABI 2010)
• Closely linked to human activities

3. Weeds
- if unmanaged - greater yield losses than any other
crop pest (Oerke and Dehne 2004)
- Expensive:
- £105 million annually in crop losses in Britain
- £90 million annually for herbicides
(Williams et al. 2010)
- increasing problems with herbicide control
(regulations, resistances)
- great chance to increase research efforts into non-
chemical management options!

4. Using citizen science for weed management
• Project proposal to increase use of non-chemical
weed management in arable farming
• Participatory project: workshops with farmers
• Farmer/agronomists to collect/report weed and
management data

5. EpiCollect Software

6. EpiCollect software – collecting weed data

7. EpiCollect software – collecting weed data

8. Case study: Solanum elaeagnifolium
Silverleaf nightshade, tomato weed
perennial weed
reproduction by seeds and root
fragments
distributed with contaminated
seeds, fodder, hay, soil, machinery,
sheep, birds….
prefers warm-temperate regions,,
drought tolerant.

9. Case study: Solanum elaeagnifolium
- native in Mexico
- currently expanding its range in southern Europe
favoured by climate change
- listed species in Europe (EPPO A2)