Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Relationships between the number of seeds in the cones of Norway spruce Picea abies (L.) Karst. and their damage by insects in the Beskid Śląski Mountains and the Beskid Żywiecki Mountains.

Abstract

Length of cones, and total number of seeds, number of viable and infertile seeds, and number of seeds damaged by insects in the cone, were analysed in cones of Picea abies collected in selected stands at 5 sites each in the Polish Beskid Śląski Mountains (a region affected by industrial air pollution) and Beskid Żywiecki Mountains (an almost pollution-free area) in 1995. Cones were randomly selected from trees growing at 6 altitudes between 700 and 1200 m altitude at each site (a total of 195 cones, including 105 from the Beskid Śląski Mts.). Cone length was measured, seeds were counted from individual cones (a total of 55 146 seeds, including 29 451 from the Beskid Śląski Mountains). The number of seeds with damage by cone insect pests (Cydia strobilella, Dioryctria abietella, Strobilomyia anthracina, Plemeliella abietina) was estimated (a total of 8401 seeds, including 3399 from the Beskid Śląski Mountains). A cutting technique was used to analyse 11 700 seeds (60 randomly selected from each cone) in order to calculate the percentage of the viable seeds as well as the infertile seeds and those infested by insect larvae. Statistical analysis showed that there was no definite correlation between the variables recorded in either region. Almost all samples were infested by P. abietina, which destroyed 0.33-42% of seeds; losses occurred irrespective of the number of viable seeds in cones.