Ecology & Management of Bark-Beetle Forest Pests

Some scolytid pests Some bark -beetle pests - Dendroctonus micans Dendroctonus micans Some scolytid pests Ecology and Management of Bark-Beetle Forest Pests 1. Dendroctonus micans 2. Ips typographus 3. Trypodendron spp. Jean-Claude Grégoire Biological Control and Spatial Ecology Lab 4. Scolytus multistriatus Université Libre de Bruxelles, Belgium 5. Scolytus scolytus [email protected] 6. Dendroctonus ponderosae

Some bark -beetle pests - Dendroctonus micans Some bark -beetle pests - Dendroctonus micans Some bark -beetle pests - Dendroctonus micans

1 Some bark-beetle pests - Dendroctonus micans Some bark -beetle pests - Dendroctonus micans Some forest pests - Dendroctonus micans

Some forest pests - Dendroctonus micans Some forest pests – Ips typographus Some forest pests – Ips typographus Ips typographus

Kielder forest (43,000 ha in England + 50,000 ha in Lothian & Strathclyde : Border) and surrounding area: main concern. 200,000 ha of Sitka

North Yorkshire : Ae Forest (40,000 ha). 9,000 ha Total Dumfries & Galloway: Sitka = 104,000 ha; Norway = 5,000 ha

Kent: Ashford. 40- 50 sites, all of which with R. South Molton grandis (Devon). 1 site

D micans infested zones Unattacked zones, survey planned

2 Some forest pests – Ips typographus Some forest pests – Ips typographus Some forest pests – Trypodendron spp. Trypodendron spp.

Some forest pests – Trypodendron spp. Some forest pests – Scolytus spp. Some forest pests – Scolytus spp.

Scolytus multistriatus; S. scolytus Insects

Symptoms

Fungi

Scolytus multistriatus Ophiostoma ulmi, O. novo-ulmi Scolytus scolytus

3 Some forest pests – Scolytus spp. Some forest pests – Scolytus spp. Some forest pests – Scolytus spp. Scolytus multistriatus Scolytus scolytus

Cycle

Some forest pests – Dendroctonus ponderosae in British Columbia. Some forest pests – Dendroctonus ponderosae in British Columbia. Integrated Pest Management of Dendroctonus ponderosae Dendroctonus ponderosae bark beetles

• Quarantine • Silvicultural practices • Tree resistance • Biological control • Semiochemicals • Pesticides

4 Quarantine Quarantine

Integrated Pest Management of 28 Scolytid species intercepted in Great-Britain, 1980-1988

bark beetles Species Origin Port of interception 1 Crypturgus borealis Russia Hull 2 C. hispidulus Russia Hull 3 C. pusillus Canada Seaforth Dock • Quarantine France Southhampton 4 C. subscribosus Sweden Shoreham • Silvicultural practices 5 Dendroctonus brevicomis Canada Merseyside 6 D. pseudotsugae Canada Newport • Tree resistance 7 D. rufipennis Canada 12 localités 8 Dryocoetes affaber Canada 9 localités • Biological control 9 Gnathotrichus sulcatus Canada Tilbury 10 Hylastes ruber Canada Newport; Erith • Semiochemicals 11 Hylurgops porosus Canada 5 localities 12 H. rugipennis Canada 3 localities • Pesticides 13 Ips amitinus Poland Portsmouth USSR Ellesmere 14 Ips duplicatus USSR Ellesmere 15 Ips latidens Canada Newport 16 Ips pini Canada Dudley 17 Ips typographus Germany; Norway; Sweden, Poland, USSR 13 localities 18 Orthotomicus caelatus Canada Dudley; Teesport 19 Orthotomicus proximus Finland Boston

Wainhouse, D. 2005. Ecological Methods in Forest Tim Winter, Forestry Commission, pers. comm. Pest Managment . Oxford University Press.

Quarantine Silvicultural practices Silvicultural practices Wainhouse, D. 2005. Ecological Methods in Forest Thinning Pest Managment . Oxford University Press. Felling time

The effect of stand management after windblow on the number of Norway spruce killed by Ips typographus in Sweden

Healthy beeches were felled sequentially every week from December 2000 to March 2001 They were treated with a pyrethroid insecticide, and equipped with lateral strips of mosquito netting

Wainhouse, D. 2005. Ecological Methods in Forest Pest Managment . Oxford University Press.

5 Silvicultural practices Silvicultural practices Silvicultural practices Wainhouse, D. 2005. Ecological Methods in Forest Felling time Felling time Felling time Pest Managment . Oxford University Press.

Insects killed at landing and caught in the netting were regularly counted

Total catches per trap-tree according to felling date

3000 29-Dec 2500 T. domesticum T. signatum 2000 1500

1000 04-Jan 19-Jan 22-Dec Total catches Total

500 12-Jan 16-Mar 23-Mar 09-Feb 09-Mar 26-Jan 23-Feb 30-Mar 02-Mar 02-Feb 16-Feb 0 30-Nov 20-Dec 09-Jan 29-Jan 18-Feb 10-Mar 30-Mar 19-Apr

Felling date

Biological Control Biological Control Biological Control Biological control Biological control Biological control

Eilenberg et al. (2001): Classical biocontrol Conservation biocontrol ‘The use of living organisms to suppress the population density or ‘The intentional introduction of an exotic, usually co-evolved, biological ‘Modification of the environment or existing practices to protect and enhance impact of a specific pest organism, making it less abundant or less control agent for permanent establishment and long-term pest control’ specific natural enemies or other organisms to reduce the effect of pests’ damaging than it would otherwise be’ Exotic pest – Exotic, coevolved natural enemies

• Classical biocontrol Enhancement of native natural enemies against Ips typographus • Inoculation biocontrol • Inundation biocontrol Rhizophagus grandis against Dendroctonus micans • Conservation biocontrol

Eilenberg, J., A. Hajek and C. Lomer. 2001. Suggestions for unifying the terminology in biological control. BioControl 46: 387–400

6 Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biology of D. micans Biology of D. micans Rhizophagus grandis against Dendroctonus micans Sex-ratio is strongly female- biased (1:10 to 1:40) The female tries to bore an egg gallery in an apparently healthy The females are fertilised by tree. It often has to repeat its their brothers before attempts because of host emergence. The species is resistance (resinosis, perhaps extremely resistant to the lignin). chemical defences of spruce (monoterpenes). Therefore, the The female lays its eggs in insects do not need to aggregate batches. on a tree (differing, e.g., from The living tree protect the insects Ips typographus ), and to kill it from interspecific competition before they can establish. and generalist natural enemies. Each female can thus start a new colony on its own.

Photo : Forestry Commission UK

Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biology of D. micans D. micans et R. grandis are moving westerward Spread of D. micans and of R. grandis

Dendroctonus micans is presently expanding in France and in the United Kingdom .

There could be several years between the arrival of the pest and that of the predator. In areas isolated by geographical barriers (Caucasus, United- Kingdom) the predator may even never follow. Artificially introducing R. grandis is The larvae feed Pupation occurs in individual niches Dendroctonus micans has not yet completed its progresses in France and Great- collectively. They created in the frass which fills the brood Britain. Ireland is stll untouched. of particular relevance in these produce aggregation chamber. In the newly colonised areas, D. micans causes substantial damage. cases. pheromones After several years, these damage decrease. This decrease is systematically correlated with the appearance of R. grandis, which follows D. micans .

7 Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans D. micans and R. grandis in Germany and Belgium Biology of R. grandis Biology of R. grandis specific attractants In 1901, in Germany, Bergmiller described Rhizophagus grandis in the brood chambers of D. micans . He observed that the predator was abundant, specific, ubiquitous et voracious Its life within a living tree which

100 produces toxic monoterpenes protects D. micans against most of 80 the generalist natural enemies. However, its specific predator, 60 D. micans entered Belgium in 1898. Rhizophagus grandis, is also extremely resistant to the host-tree's Rhizophagus grandis was discovered 40 monoterpenes. for the first time in 1945. Presently, R. grandis followed D. micans in its it colonises >90% of D. micans' 20 progression westward. subcortical brood chambers although they are very scarce (1 - 2 per 0 The adults locate their prey using 2 3 4 5 L hectare). L L L chemical signals present in adult and larval frass. These attractants were identified in several experiments: Nymphes

Proportion of galleries colonised (%) colonised galleries Proportion of (+) -terpinene-4-ol, (+) -fenchol, (S) -(-)-borneol, dominantes

1 α

L (S) -(-)-verbenone, ( -)-fenchone, racemic camphor, -terpineol. Jeunes adultes Chambres vides Galeries de ponte

Age of the galleries Grégoire, J.-C., D. Couillien, R. Krebber, W.A. König, H. Meyer & W. Francke (1992). Chemoecology , 3: 14 -18.

Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biology of R. grandis Biology of R. grandis Biology of R. grandis specific attractants specific attractants oviposition stimuli

The adults, males and females, By comparing (GC-MS) extracts of frass of D. enter the prey's brood chambers micans and of D. valens (which also induces and attack all immature stages. oviposition in R. grandis ), it was possible to identify common chemical compounds: Oviposition occurs in the frass. It is • (+) -terpinene-4-ol triggered by specific chemical • (+) -fenchol signals. • (S) -(-)-borneol • (S) -(-)-verbenone •(-)-fenchone, • racemic camphor

Oviposition experiments showed that these These attractants were identified in several experiments: oxygenated monoterpenes are oviposition (+) -terpinene-4-ol, (+) -fenchol, (S) -(-)-borneol, stimuli for R. grandis . (S) -(-)-verbenone, ( -)-fenchone, racemic camphor, α-terpineol.

Grégoire, J.-C., D. Couillien, R. Krebber, W.A. König, H. Meyer & W. Francke (1992). Grégoire, J.-C., D. Couillien, R. Krebber, W.A. König, H. Meyer & W. Francke (1992). Grégoire, J.-C., M. Baisier, A. Drumont, D.L. Dahlsten, H. Meyer & W. Francke (1991). Journal Chemoecology , 3: 14 -18. Chemoecology , 3: 14 -18. of Chemical Ecology , 17(10): 2003 -2019.

8 Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biology of R. grandis Biology of R. grandis Biology of R. grandis facing limited resource larval biology gregarious behaviour of the larvae

Egg-laying regulation mechanisms The larvae feed upon all The larvae are attracted towards a The mean number of eggs laid per female decreases linearly as the immature stages. wounded prey. They respond in particular number of females increases. They aggregate on a wounded to (-)-myrtenal. They produce (-)-myrtenal prey. Very often, the prey have themselves and seem to use it as an This prevents overexploitation of the brood chambers' limited been wounded earlier by an aggregation pheromone. resources adult R. grandis . 140 16 120 14 100 12 80 10 60 8 40 6 temps (min) temps 20 4 Average numbers of eggs eggs of numbers Average 0 2 1 2 3 The prepupa leaves the subcortical Number of females 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 brood chamber, and pupates in the Moyenne des captures Average numbers of eggs per box, litter at the base of the tree. with 1, 2 or 3 females per box

Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans R. grandis against D. micans R. grandis against D. micans R. grandis against D. micans : rationale history rationale

Rhizophagus grandis follows its 1 2 The first technique consisted in prey in its geographic expansion . introducing predators in fresh However, this is often a lengthy spruce logs infested with D. process which could be shortened micans larvae. When the prepupae by artificially releasing the leave the logs, they fall in a large predator. funnel and then on a tray. They The delay which is observed in R. are collected severl times a day 3 4 and put into containers filled with grandis ' natural spread is sand, where pupation will occur. connected, e.a., to the The logs are "black boxes", and dicontinuous distribution of spruce this method does not allow any stands. control of diseases, such as In Haute-Loire, for example, the Beauveria bassiana. spruce stands are on the tops of D. micans arrived in the French Massif central at the beginning of the D. micans R. grandis '70s. R. grandis did not follow and had to be released. Mass-rearing and ancient volcanoes; they are releases started in 1978 in co-operation with the INRA and with separated from each other by vast European and French fundings. extents of agricultural land.

9 Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans R. grandis against D. micans : R. grandis against D. micans : mass-production quality control on take-off, fecundity R. grandis against D. micans : impact and response to attractants

In order to reduce the incidence of

Beauveria bassiana , a semi- r = 0.89 • Take-off capacity culminates 2.5

artificial method was developed, TAKE-OFFRATE (transformed) at 80%, 3 weeks after How to assess impact ?? first in glass test-tubes filled with emergence, then decreases by • Release plots versus control plots fresh bark, bark powder and living 2.0 larvae of D. micans . 8% every month. r = 0.90 • Establishment of the predators Routine control • Reduction in attack density Later, the tubes were replaced by 1.5 clear polystyrene boxes. • Fecundity varies according to the rearing conditions. 1.0 Later again, synthetic oviposition Control on samples • Release plots versus control plots : impossible in stimuli are used in the rearings; an this case. Forest stands are too different from artificial diet is also developed for • Response to attractants: 0.5 each other to allow correct matching the larvae of R. grandis . Control on samples

in a windtunnel 0.0 0 1 2 3 4 5 6 7 8 91011 AGE (months)

Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans R. grandis against D. micans : impact R. grandis against D. micans : impact R. grandis against D. micans : impact

1984 1985 1986 Reduction in attack density Unattacked tree Establishment: 17% Establishment: 48% Establishment: 54% D. micans A sampling (N=60) (N=54) (N=59) D. micans + R. grandis technique based 50 m upon permanent Attacked «transects» is tree Release plot established after calibration of the Release plot method in a 3ha 42% stand. 30% 73% 38% 33% 36% Beyond ca 100 trees, 50% 50% 43% the proportion of 66% 40% attacked trees Establishment becomes stable. One year after the first mass-release in 1983, the treated stand (FD du 1/2 = 50% Goulet, Lozère) was regularly followed during several years. Rhizophagus grandis Predators were found in brood systems up to 200 m from the release zone. Establishment: stand colonisation by 0/1 = 0% Annual censuses revealed that a growing proportion of the galleries sampled were colonised by the predators :

10 Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Rhizophagus grandis against Dendroctonus micans Biological Control - Conservation biocontrol : the case of Thanasimus formicarius R. grandis against D. micans : impact R. grandis against D. micans : impact Conservation biocontrol Monitoring D. micans' population density The case of Thanasimus formicarius A sampling Monitoring D. micans' technique based upon permanent population density «transects» is established after A serie of permanent transects was calibration of the monitored during several years after the method in a 3ha releases in various stands in the release stand. zone. The proportion of attacked trees Beyond ca 100 decreased in all stands, as well as the trees, the numbers of D. micans per brood , whilst proportion of the R. grandis : D. micans ratio increased.

attacked trees m c

becomes stable. 1

Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius

T. formicarius is an extremely efficient predator of bark beetles. Impact of Thanasimus formicarius in the Vosges One adult eats 1-2 adult bark beetles per day, lays 60-100 eggs, and each larva eats 60 bark beetle larvae during ist life. Impact de Thanasimus formicarius sur Ips However, catches in pheromone traps are extremely typographus - 2001-2004 It responds to aggregation pheromones if many bark beetle species, unfrequent in Belgium.

including Ips typographus , and is frequently caught in pheromone 200.000 traps. Norway (1977) 1 Thanasimus / 3.9 Ips 180.000 (Bakke & Kvamme 1978) 160.000 y = 698299x -0,5094 Germany (1988-89) 1 Thanasimus / 456.9 Ips par par site 2 140.000 R = 0,4067; p = 0,0008 (Chr. Heidger, pers. comm.) 120.000 Sweden (1996) 1 Thanasimus / 500 Ips 100.000

an (M. Schroeder, pers. comm.)

Ips typographus 80.000 Slovakia 1 Thanasimus / 57 Ips

60.000 (Rudinsky et al. 1971)

40.000 Belgium, 1988-1996 0 Thanasimus / 483,000 Ips 20.000 Captures totales totales Captures 0 0 100 200 300 400 Captures totales T. formicarius par site par an

11 Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius It was first thought that the insect was rare or absent in the It was first thought that the insect was rare or absent in the It was first thought that the insect was rare or absent in the country, but it became soon apparent that it is abundant in, or country, but it became soon apparent that it is abundant in, or country, but it became soon apparent that it is abundant in, or near, pine stands and readily responds to pheromone traps in these near, pine stands and readily responds to pheromone traps in these near, pine stands and readily responds to pheromone traps in these locations. locations. locations. 1.2

20 1.0 spruce STATION B 18 Catches in the Forêt de Soignes pine 0.8 800 m 16

experiment 1996 10 m 14 density (/ha) 0.6 spruce C 12 COUNTED LARVAE 0.4 100 m 10

B D 8 0.2

Thanasimus C STATIONSTATION A A STATION B 6 A 0.0 10 m

A T. formicarius'

4 1993: trapping experiment, 45229 Ips caught; 10 m D d h s experiment 1996 a ri ris 2 trees sampled, 12758 Ips counted; spruce stand pine stand road larch road road arch st st NUMBER OF NUMBER 2 beech b broad e B +beec +b +b e+l v no Thanasimus found 100 m e n rch+bro ne pi syl sylve 0 a eech+ pin pi larch s s b nu u Pi spruce logs pine logs ruce+l 10 m beech+larch+broad ra+Pin sp g spruce stand pine stand ni pine/pine stands s pine/spruce spruce/pine nu Pi spruce logs pine logs spruce/spruce

It was first thought that the insect was rare or absent in the On spruce : bark too thin for pupation country, but it became soon apparent that it is abundant in, or An hypothesis was then explored: the possibility that T. near, pine stands and readily responds to pheromone traps in these formicarius might find unfavourable conditions for pupation in the locations. too thin bark of spruce. Laboratory studies confirmed this Proportions of pupae and adults 1.00 hypothesis. 0.90 0,70 Catches in the Ardennes (N = 30) 0.80 pine 0,60 spruce + paper 0.70 spruce

0.60 0,50 density (/ha) density (N = 54) 0.50 (N = 57) (N = 40) 0.40 0,40 0.30 0,30 0.20 T.formicarius' 0.10 (N = 40) 0,20 0.00 Proportions of pupae + adults (+ S) (+ + adults pupae of Proportions e s h e d ad ad la las c a o o g ar pin ro 0,10 (N = 54) (N = 57) as+fir broad ement l l spruc +broad ou e+larch e+br e ag doug n c ine+br las+broad i u pin p e+d p r + man ug pine+spruce erous+broad sp o 0,00 uce+doug spruc las+larch+b r conif sp spruce uce+d r doug 1 2 3 sp stands Series

12 Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius Biological Control - Conservation biocontrol : the case of Thanasimus formicarius On spruce : bark too thin for pupation On spruce : bark too thin for pupation On spruce : bark too thin for pupation Pupations 2,0 Emigration of larvae Pine 3.0 1,8 Spruce Spruce + "papier mâché" Pine 1,6 Spruce + 2.5 2 paper R = 0.6029; p < 0.0001 1,4 Spruce + 2.0 paper 1,2 Spruce 1,0 1.5

0,8 Pine 1.0 of pupae +of pupae adults 0,6

Transformedproportions 0,4 R2 = 0.587; 0.5 p = 0.00002

0,2 of log larvae leaving proportions Transformed

0,0 0.0 1 6 11 16 21 1 6 11 16 21 Bark thickness (mm) Bark thickness (mm)

On spruce : bark too thin for pupation On spruce : larvae leave the trees Impact of Thanasimus formicarius in the Vosges Rapports Ips typographus / T. formicarius 49 ± 57 larvae per tree in the 200000 9 funnels Guebw iller Bertrix, 1992 180000 8 Stand containing pines 7 160000 Stand containing no pines 6 140000 5 Donon 120000 4 Guebw iller Donon 100000 Guebw iller 3 Ipstypographus Donon Deux-Lacs 2 80000 Steinbach

1 Capturesd' 60000 Deux-Lacs Deux-Lacs Bark thickness Bark (mm) Deux-Lacs Hanau 0 Guebw iller 40000 Hanau 0 2 4 6 8 10 12 Steinbach Steinbach Hanau Height on tree (m) 20000 Steinbach

0 0 50 100 150 200 250 300 350 400 ca 10 larvae per pitfall trap Captures de Thanasimus formicarius par site par an

13 Semiochemicals Semiochemicals Semiochemicals

Detection Detection Trypodendron domesticum

Trypodendron Detection Semiochemicals for different uses domesticum

# • Detection

• Monitoring and prognosis #

• Control : mating disruption # #

# • Control : mass-trapping # # # # #

# # • Control : other prospects # #

# # N # # # # # #

# # # # # # # # # Ambrosia-beetle catches #

# # 20 #

# # # 40 # # # # # 100 # First trapping campaign # # Second trapping campaign # 250 0 500 1000 1500 Meters

Semiochemicals Semiochemicals Semiochemicals Detection Mass-trapping Mass-trapping

Ips typographus Trypodendron domesticum 2500 Xyleborus dispar Trypodendron signatum & lineatum 2000 Xylosandrus germanus

1500

1000

Ips typographus 500 Capturesmoyennespar piège 0 Wellin Betrix Villers Flobecq Meerdael Marche- La Roche La Presgaux Lindgren funnel trap Theysohn trap les-Dames Sites

14 Semiochemicals Semiochemicals Semiochemicals Mass-trapping Mass-trapping Mass-trapping

Cost-effectiveness ?? Trap-trees Trap-trees versus artificial traps Ips typographus Ips typographus Pheromone-baited, poisonous trap-trees

• 1 m³ produces 30 to 35,000 insects; • 5,000 beetles are needed to "kill" 1 m³ Ips typographus • One trap catches, on the average, 10,000 insects • 3.5 traps are needed to collect the insects from 1 m³ • 1 trap + 1 pheromone dispenser cost 20 to 40€ • 1 m³ sells at 20-30€ (2008 prices, Belgium )

Pheromone traps