Management of diseases in Norwegian Christmas tree plantations

ABSTRACT

In integrated pest management (IPM), the goal is to keep the impact of damaging agents below a threshold level with reduced pesticide use. The present review is focusing on IPM of fungal diseases and Phytophthora root rot in Norwegian Christmas tree plantations. Healthy transplants are of vital importance to give the production a good establishment. Sanitation of diseased material and weeds is also very important in IPM. Management strategies will vary with the disease-causing agent in question, therefore, correct identification is necessary. The major pathogens are within the kingdom’s Fungi (e.g. Neonectria neomacrospora) and Chromista (e.g. Phytophthora spp.). They depend on relatively high humidity or free moisture to spread and infect. Any factors diminishing the duration of wet conditions will, therefore, reduce the disease pressure. Efficient weed management in Christmas tree fields will increase air circulation and thereby ensure a quicker drying after precipitation. Furthermore, certain weed species are host plants for rust fungi on Christmas trees, and thus, removal of the alternate host is a highly relevant control strategy. In Norway, fungicide use in Christmas trees is limited and only recommended during the short period from bud break to fully elongated shoots, generally the most vulnerable period concerning fungal attacks.

KEYWORDS:

• Abies
• fungi
• integrated pest management
• pathogens
• Phytophthora
• spruce
• weed

Acknowledgements

We want to thank Trude Slørstad, Andrew Dobson and Marit Helgheim at NIBIO and Kathy Riley at Washington State University (WSU) for valuable technical assistance. Furthermore, we specifically want to thank Gary A. Chastagner at WSU, Iben M. Thomsen at Copenhagen University, and the Norwegian Christmas tree extension service and their members for nearly two decades of close collaboration.

Disclosure statement

The authors declare no conflict of interest.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The work was mainly financed through grants from the Research Council of Norway and Skogtiltaksfondet [Norwegian Forestry Fund].