Defoliators – Management Direction

1. Defoliators – Management Direction

2. Numerous insect & disease defoliators periodically reach outbreak levels challenging management goals and options. Numerous insect & disease defoliators periodically reach outbreak levels challenging management goals and options. Dothistroma

3. Long-term strategies for defoliators include, but are not limited to: • host species management; • age and species mosaics across the landscape; • silviculture treatments to lessen susceptibility of trees and stands; • long-term plans for managing susceptible species; • hazard & risk rating of all susceptible landscapes; and • incorporation of climate change into population modeling • Short-term tactics for defoliators include, but are not limited to: • annual detection (air and ground); • population sampling in historic outbreak areas; • establish & maintain permanent population monitoring sites; • monitor weather patterns to determine stress level of forests and insect response; • biological insecticide treatments when threshold levels of damage/insects are reached.

4. Highlights of Management Strategies for 3 major Defoliators in the SIR Western spruce budworm Choristoneura occidentalis Douglas-fir tussock moth Orgyia pseudotsugata Western hemlock looper Lambdina fiscellaria lugubrosa

5. Key ingredients we must know about defoliators • Life history, host preferences and organism response to changing environments and management regimes • Dispersal and outbreak dynamics in changing forest environments (changing/expanding ranges) • Incipient phase and key environmental triggers • Impacts at tree, landscape and ecosystem level Chronic Eruptive

6. Douglas-fir tussock moth, Orgyia pseudotsugata Tussock moth is a cyclical defoliator of dry-belt Douglas-fir in the south central interior of BC. Tussock moth is typically found at very low elevations often in mixed Ponderosa pine-Douglas-fir forests. Recently these ecosystems have seen high losses of Py from MPB and remaining Df are now at risk. Site near Kamloops showing severe 2007 tussock moth defoliation mixed with low levels of western spruce budworm, and Ponderosa pine mortality from MPB.

7. Douglas-fir tussock moth outbreak dynamics in B.C.

8. After the collapse of the DFTM outbreak in the early 1980’s, the BCMOF implemented an operational, integrated pest management program. Egg mass surveys Trapping Surveys Virus application

9. IPM Objectives for DFTM: • detect increasing populations at an early stage; • locate and delineate building populations prior to visible defoliation; • apply OpNPV to sites expected to sustain unacceptable levels of damage; and, • ensure a coordinated program that would respond quickly and effectively to a developing outbreak. OpNPV = Orgyia pseudotugata nuclear polyhedrosis virus

10. Average annual moth catch per 6-trap clusters 2007

11. Several comparisons using Virtussand TM Biocontrol-1, were conducted over the course of the 1991-93 outbreak. They included: • Stored versus newly produced Virtuss; • Virtussversus TM Biocontrol-1; • Alternate swath application (35 m swaths every 200 meters ); and, • Reduced dosage All treatments proved successful!

12. Virtuss

13. 21 permanent trapping sites (6-trap clusters) established in areas of historic defoliation plus singlets in target areas

14. Heffley Creek Robbin’s Range Six Mile Ranch Barnes Lake

15. Why did I just tell you all of this? It’s back!!

16. Robbins Range-Happy Valley

17. Barnhartvale

18. Six mile-Beaton Creek

19. Heffley Creek-Palmer Forsythe

20. Planned action for 2008: Virus Virtuss TM Biocontrol-1 • Complete delineation of areas “at-risk” • Information session for private landowners affected • Treat incipient populations w virus (Crown & private lands) • Efficacy assessment and continue monitoring program 2.0 x 1010 PIBs per gram 2.68 x 109 PIBs per gram

21. Western hemlock looper, Lambdina fiscellaria lugubrosa • eruptive defoliator of western hemlock forests • Special management issues (e.g. Mountain Caribou habitat) may necessitate control actions • Hazard/risk rating • managing chronic/susceptible ecosystems • Monitoring • B.t.k. is an option

22. Western Spruce Budworm, Choristoneura occidentalis • Periodically erupts to outbreak levels and causes widespread damage • Largest WSB outbreak in recorded history (1985-1993) covered >830,000 ha in 1987 • 1987 outbreak was temporally more synchronous across more sites than previously recorded • The current outbreak now covers >760,000 ha and has expanded into “new” areas

23. Annual area defoliated by western spruce budworm in B.C. 1909-2006 Coastal sea level Coastal range Coastal range & Southern Interior Southern Interior & Cariboo Graph from CFS

24. Budworm defoliation

25. Results of egg mass sampling: 2008 WSB defoliation prediction

26. Ha WSB defoliation in “old Kamloops Region” 756,000 ha in SIR

27. Budworm Aerial Spray Program: • Foray 48B (Bacillus thuringiensis var. kurstaki) • 2008 planned treatment 60,000 ha

28. History of defoliation and B.t.k. treatments in SIR

29. Layer 1 - low mortality, some topkill Layer 2 - low mortality, moderate topkill Layer 3 - highest mortality & topkill Layer 4 - combination of 2 age classes - high mortality in suppressed trees

30. Budworm Aerial Spray Program priorities: • Douglas-fir dominated sites • multi-canopy structure with layer 3 & 4 “at risk” • in-stand pine mortality • history of selective harvest or thinning • drier sites • high hazard stands (Maclauchlan et al. 2006) • min. one year moderate-severe defoliation of layers 3, 4 • >two years light-moderate stand defoliation • majority of area predicted moderate or greater defoliation in next season • management goals compromised if damage continues • Multiple-use issues compromised

31. Estimated application cost for 2008 western spruce budworm program of 60,000 ha