Screening spruce for white pine weevil resistance

• Project description
• Distribution of P. strobi in North America
• Genetic variation in canadian weevil populations
• Range of Sitka spruce
• Sources tested for resistance in Western North America
• White pine weevil resistance screening trials
• Mass screening for resistance (Jordan River plantation)
• Ghost trial: studies using caged insects clarified the mating system of weevils
• Artificial wounding studies: Studying plant defenses
• Insect - plant relationships
• Are weevil resistant trees also resistant to other insects?
• Conclusions
• Selected references

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White pine weevil resistance screening trials

Results of white pine weevil resistance screening trials: site, year planted, number of families/clones, number of trees, year of weevil enhancement, and number of resistant families/clones

Site	Year planted	No. of families/ clones	No. of trees	Year of weevil enhancement	No. of resistant families/ clones
Sitka spruce families
Big Tree Creek, Sayward	1974	321	4389	--	11
Jordan River	1991	75	1722	1994	4
North Arm, Cowichan Lake	1992	75	1477	1996	4
Hamlet, OR	1994	24	2104	1997*	3
Nehalem (South Coal), OR	1994	24	2116	1997*	3
Browns Main, Port Renfrew	1994	72	807	1997	1
Snowden Forest, Campbell River	1994	72	1336	1999	1
Camp 4. Campbell River	1995	84	2129	1999	0
Coombs Pub	1999	126	2940	2003	in progress
Beaudry, Harrison Mills	1999	126	2888	2002	in progress
Sitka spruce clones
Kaouk River, Fair Harbour	1984	38	629	--	11
Espinosa Creek, Zeballos	1991	151	2331	--	uncertain
Armishaw + Glenroy, Sayward	1992	169	2581	1996	uncertain
Interior and white spruce
Quesnel	1973	174	11389	--	4
Camp Creek, Clearwater	1984	139	4332	--	8
Herring Creek, Prince George	1986	368	10484	--	in progress
Skimikin -SA, Tappen	1990	250	10374	2002	in progress
Skimikin -TO, Tappen	1990	180	6204	2003	in progress
Kalamalka Research Station	1995	42	3001	1999	15

* weevil enhancement conducted by Oregon Dept. of Forestry, using method different from CFS

Since 1974 twenty BC Ministry of Forests trials have been screened for resistance to the white pine weevil. These tests included a total of 80,181 trees.

This mass screening required assessing attack rates in well-replicated family trials. To accelerate the screening process the indigenous weevil populations at thirteen of the B.C. sites were enhanced by placing 2 to 4 adult weevils on each tree. This created a uniform weevil pressure throughout the test site.

Infested plantations were monitored for several years to determine resistance to weevil attack. Using this procedure, trials can be screened effectively and inexpensively in 3 to 4 years after planting. Several resistant families and individuals have been identified. Four locations in BC provided resistant sources.
 

Resistant spruce populations in British Columbia

Locations where Sitka and Interior spruce families with resistance to white pine weevil have been identified.

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