Forest characteristics affecting the rate of shoot pruning by the pine shoot beetle (Tomicus piniperda L.) in Pinus radiata D. Don and P. sylvestris L. plantations
1997
Amezaga, I.
Different variables, such as altitude and presence of defoliators, were studied in Bizkaia (northern Spain) in order to assess the susceptibility of Pinus radiata (D. Don) and P. sylvestris (L.) stands to Tomicus piniperda (L.) (Coleoptera: Scolytidae). Altitudes higher than 400 m, presence of logs, degree of thinning and incidence of fires, all increased the susceptibility of P. radiata monocultures to shoot attack by T. piniperda. P. sylvestris plantations were more affected at altitudes lower than 400 m and by poor forest hygiene. The presence of the processionary moth (Thaumetopoea pityocampa Den and Schiff.) had a significant effect on the rate of shoot pruning on the trees; vigorous trees and those with bare leader were more affected by the bark beetle attack if T. pityocampa larvae were feeding on their needles, while trees with dominance taken by the side shoots were less attacked when moth larvae were present.
显示更多 [+] 显示较少 [-]