here. - Ministry of Forests, Lands and Natural Resource Operations

fo r e S t he a lt h - SP e c I a l Pr o j e c t S
2012 we S t e r n SP r u c e Bu d w o r M Pr o g r a M Su M M a r Y
Operations Summary
The 2012 western spruce budworm spray program saw a total of 116,012 hectares of Douglas-fir forest treated
with Foray 48B (Bacillus thuringiensis var. kurstaki, or B.t.k., P.C.P. No. 24977) in southern B.C. (Thompson
Okanagan, Cariboo and Kootenay Boundary Regions) (Table 1). Foray 48B was applied at 2.4 litres per hectare
on all sites for a total of 278,430 litres of B.t.k. applied in the 2012 program.
To achieve optimum foliage protection, peak 4 th instar larvae are targeted. Timing of spray is dependent upon a
number of factors including, but not limited to:
1. Foliage development – new shoot must be flushed and elongating;
2. Insect development – most budworm larvae should be in the 4 th instar, but there will be some at earlier
and later stages of development when treatment is applied; and,
3. Weather – preferably dry and warm so that larvae feed actively and ingest B.t.k. immediately after
spray.
The above diagram describes the relationship between B.t.k. application timing, shoot development,
and western spruce budworm larval instar stage.
Ministry of Forests, Lands and Natural Resource Operations, Kamloops, B.C.
40