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
Hazard rating
To complete its life cycle, the white pine weevil requires a heat accumulation of 888 and 785 degree days above a threshold of 7.2°C in coastal and interior British Columbia, respectively (McMullen 1976, Spittlehouse et al. 1994). Degree day accumulation varies with latitude, elevation, slope and aspect.
Heat Sums v/s Elevation for the Interior of British Columbia
Long description: Heat sums v/s elevation
This graph illustrates heat accumulation (degree days) (y axis) over a threshold of 7.2 degrees C at various elevations (m) (x axis). In the interior of BC, a location is considered low risk for weevil damage at elevations above 930 m where heat accumulation does not reach 785 degree days. (Graph adapted from Spittlehouse et al. 1994)
| Elevation (m) | Heat sum (degree days) |
|---|---|
| 500 | 1100 |
| 600 | 1020 |
| 700 | 940 |
| 800 | 860 |
| 900 | 780 |
| 1000 | 700 |
| 1100 | 627 |
| 1200 | 554 |
| 1300 | 470 |
Under Quebec conditions, a susceptibility map describing five hazard zones was drawn by Boulet (1995) from insect surveys made between 1984 and 1993. Infestations start earlier, the annual rate of attack is higher in areas where attack probability is high, and weevil populations are still spreading with new areas affected every year.
Under Maritimes conditions, it appears that the white pine weevil is common and widespread and the incidence is increasing in New Brunswick, Nova Scotia and Prince Edward Island.
Project status
- On-going