Lophodermium piceae in Norway Spruce Needles Effects of Drought and Irrigation : Shoot and Foliage Diseases in Forest Trees. Proceedings of a Joint Meeting of the Working Parties Canker and Shoot Blight of Conifers (S2.06.02) Foliage Diseases (S2.06.04)

Florenz

1995

S. 1-5

14 Lit. Ang.

Bandaufführung

13577

77369

The occurrence of Lophodermium piceae in healthy green needles was estimated in a 30-year-old experimental stand of Norway spruce in southern Sweden that had been divided up into plots subjected to irrigation (I), irrigation and fertilization (IF), drought (D) and no treatment (C). In August, frequencies oc needles with Lophodermium piceae were slightly lower in the irrigated plots than in the nonirrigated ones. Infection frequencies were similar in the C and D plots, probably owing to the dry summer weather. Frequencies of current-year and 1-year-old needles containing the fungus increased by 10% in nonirrigated trees and 30% in irrigated ones from August to November. As a result, the difference between the nonirrigated and irrigated plots decreased. The results indicate that the availability of water to the root system indirectly influences needle susceptibility to Lophodermium piceae colonization.