White pine weevil management
- Weevil management
- Sampling to assess weevil attack
- Hazard rating
- Silvicultural methods of control
- Better site selection
- Resistance to attack
- Fertilization and weevil attack
The recommended approach for control of the white pine weevil, Pissodes strobi (Peck), is to apply an Integrated Pest Management system (IPM) (Alfaro et al. 1995) in which several tactics are combined. Individually, each of these methods brings only partial control. The combined system includes hazard rating, silvicultural control, use of genetic resistance and direct control. In British Columbia, these management options can be evaluated using the SWAT (Spruce Weevil ATtack) Decision Support System. Plantations should be started at close densities (2.5 m spacing or less) and volunteer shade trees should be retained. Mixing spruce with other suitable species is recommended, especially in high hazard zones. Thinning and brush control should be delayed as much as possible. When available, resistant trees (Alfaro 1996) should be used, always in mixtures with susceptible stock. Pruning of multiple tops to leave only one leader should be conducted when economically feasible.
Impacts of weevils on yield of Sitka spruce under low, medium or high hazard conditions. Simulations run with 2500 stems / ha and a site index of 25.