My main research is on diseases in forest nurseries and after out-planting but I am also interested in the development and effect of Gremmeniella-infections on seedlings, trees and forests. I am engaged in teaching in the courses about pest and diseases in forest trees given at our department. I am also acting as a consultant for forest nurseries when they have problems with diseases on forest seedlings.

Forest nurseries

Swedish forest nurseries produce 300 - 350 million seedlings annually. There are several different fungal diseases that can attack the seedlings in the nurseries and after out planting. Some of these diseases have a long latent period between infections, to the symptoms appears and finally to the production of fruit bodies. Diagnosis could sometime be based on the symptom on the host, but in some cases it is necessary to wait until the fruit-bodies are produce, before an exact diagnosis could be done. For some fungi (Gremmeniella and Lophodermium) infection take place in summer/autumn and then the disease will develops, within the host, during winter storage while the symptoms appears first when the seedlings starts to grow in the following year. This means that there is a high risk of storing, transporting and planting out healthy looking but diseased seedlings. In this area I work to develop and use molecular methods for diagnosing different diseases during the latent phase. So far we have methods for detecting both Gremmeniella and Lophodermium during their latent period and are studying detection of other diseases.

Because of frequent appearances of diseases many nurseries use fungicides to prevent infections. Only a few fungicides are allowed to be used in forest nurseries and there is a high risk for the pathogens to become resistant. Therefore I am interested to find other suitable fungicides as well as biological control organisms, since many nurseries have an interest in reducing the amount of fungicides. Some nurseries are also situated on sensitive land areas close to lakes, rivers etc. Greymold (Botrytis cinerea) is the most common pathogen in forest nurseries and it can cause damage during the whole growing period as well as during transport and storage. For the moment I am looking for the possibility to use biological control organisms during winter storage.

Gremmeiella infection in the forest

Gremmeniella abietina cause cancer and shoot die back to conifers in the boreal and temperate forest. It is one of the most damaging fungal pathogen in Swedish forest and it can attack all ages from seedlings to mature trees. The latest and most severe epidemic was in 1999 and 2001 and was covering up to 500 000 ha and big areas had to be harvested in advance. During the last epidemic we established research sites were reforestation could be investigated as well as sites were we could follow short and long time effect on mortality and defoliation from Gremmeniella infection.