“You can’t defend. You can’t prevent. The only thing you can do is detect and respond”
(Bruce Schneier)
Welcome to the PurPest Project website
“You can’t defend. You can’t prevent. The only thing you can do is detect and respond”
(Bruce Schneier)
Welcome to the PurPest Project website
“You can’t defend. You can’t prevent. The only thing you can do is detect and respond”
(Bruce Schneier)
Welcome to the PurPest Project website
“You can’t defend. You can’t prevent. The only thing you can do is detect and respond”
(Bruce Schneier)
Welcome to the PurPest Project website
“You can’t defend. You can’t prevent. The only thing you can do is detect and respond”
(Bruce Schneier)
WEBINAR - "Healthy nursery plants"
News
- key to healthy horticulture, forestry and nature restorations -
20 April 2026
Scientific studies have demonstrated that numerous declines and diebacks affecting horticultural crops, forests and natural ecosystems in Europe, Australia and the Americas are primarily caused by invasive soil- or airborne pathogens from the genus Phytophthora. Extensive surveys conducted in more than 2,500 nurseries and a similar number of restoration and planting sites across Europe revealed near-ubiquitous infestation with over 120 Phytophthora species, most of them exotic.
Nursery accreditation schemes have been operating successfully for years in Australia, California and recently the United Kingdom. They showcase that the spread of invasive plant pathogens can be drastically reduced through effective biosecurity standards, improving plant quality while ensuring the economic viability of the nursery sector.
Epidemic Phytophthora diseases of forests and natural ecosystems and the importance of the nursery pathway – Thomas Jung (Mendel University in Brno, Czechia)
14:25
Best management practices to produce plants free of Phytophthora in nurseries for forest restoration – Bruno Scanu (University of Sassari, Italy)
14:45
Towards healthier nurseries: effective and sustainable strategies for Phytophthora management in horticulture – Ana Pérez-Sierra (IVIA, Valencia, Spain)
15:05
Coffee break
15:20
Phytophthora in British nurseries; identifying risk and which ‘best practices’ are best – Sarah Green (Forest Research, Northern Research Station, Roslin, UK)
15:40
Preventing Phytophthora spread on native and horticultural plants in California – Tyler Bourret (PhytoWorld LLC, Seattle, USA) & Susan Frankel (USDA Forest Service, Pacific Southwest Research Station, retired)
16:00
Plant Healthy: the value of a voluntary nursery certification scheme – Malcolm Catlin (Director, Plant Healthy scheme)
16:20
Questions (raised via the chat and selected by the moderator) and Discussion
16:50
Conclusion
The pathway of invasive Phytophthora pathogens from nurseries via planting activities to natural forests and best nursery management practices.A–D. The root and collar rot epidemic of alder (Alnus spp.) trees across Europe.
A. Healthy-looking Alnus glutinosa seedlings in a nursery.
B. Development of a black collar rot (arrow) caused by Phytophthora ×alni in a healthy-looking A. glutinosa nursery plant with a previously suppressed infection after 1 week of flooding.
C. Advancing bark canker (arrow) in a planted A. glutinosa tree caused by P. ×alni.
D. Extensive mortality of a riparian A. glutinosa forest caused by P. ×alni.
E–F. Cork oak (Quercus suber) decline in Southern Europe.
E. Container stand on the ground of a nursery with several cork oak plants showing chlorosis or mortality due to root rot caused by Phytophthora cinnamomi.
F. Cork oak afforestation with high mortality due to root rot caused by P. cinnamomi.
G–H. Pine seedlings in containers close to the ground with chlorosis and mortality due to irrigation with untreated river water infested with several Phytophthora species.
I–J. Healthy Myrtus communis seedlings with healthy root systems in containers on tables lifted >80 cm from the ground and irrigated with pathogen-free filtered water.
