Black stem borer
- Order: Coleoptera
- Family: Curculionidae
- Latin: Xylosandrus germanus (Blandford)
- English: Black stem borer
- French: Bostryche noir du Japon
The prevention measures discussed here apply to wood-boring insects in general. Populations of these insects increase a few years after natural phenomena such as windstorms, windthrow and ice storms that leave large amounts of deadwood on the ground.
During harvesting, avoid damaging residual trees since maintaining tree health and vigour helps to limit bark beetle populations (Katovich 2004). Felled trees should be hauled out immediately. Lastly, harvesting or pruning trees in fall or winter helps to minimize bark beetle attacks. Graf and Manser (1996) recommend the wet storage of logs, rapid felling and hauling, piling logs offsite in a dry, sunny place and chemically treating piles to keep the black stem borer in check.
1. Mechanical and silvicultural
Sanitation cutting followed by removal of the trees is the silvicultural method recommended for plantations infested with the black stem borer. Plantations of young black walnuts less than eight years old are particularly susceptible to this pest and suffer a high mortality rate (Katovich 2004). When the insect attacks piles of wood, cutting out infested portions and burning them is recommended whenever possible (IMFC 2010). The technique used in western Canada of covering piles with man-made snow and wood chips to protect trees attacked by the mountain pine beetle should also be considered, particularly during periods following major natural disturbances such as windstorms, windthrows and ice storms (Whitehead et al. 2008).
Since black stem borers tunnel fairly deeply into the wood ([Anonymous] 2000), they are resistant to most common insecticides during most of their life cycle. Contact pesticides can be used in nurseries; trunks should be sprayed with a persistent pesticide when the buds begin to swell, and repeated treatments are required (Oliver and Mannion 2001).
Fumigation with methyl iodide is used to fight the pest in wood imported to Japan (Naito et al. 2003). Chemical treatments permitted in Swiss forests have had little or no effect on stored wood; the reason for this has not yet been elucidated. Products containing chlorpyrifos are considered to be the most effective but provide only partial protection ([Anonymous] 2000). In Canada, methyl bromide, a fumigant, is registered for use against wood borers, wood destroying coleoptera including bark bettles.On-going research activities in nurseries and plantations have shown the efficacy of some essential oils extracted from aromatic plants (garlic, peppermint, rosemary, white pepper) and vegetable oils as repellents against X germanus (Ranger et al. 2009). These products are not registered in Canada.
A permethrine based insecticide is registered in Canada to control borers and bark beetles on trees and on wood piles. However, fire wood must not be treated with permethrine.
There are many different chemical pest control products available. They may be toxic to plants, animals, humans or the environment in general. A number of these products pose potentially lethal risks to humans. To protect human health and the environment from pesticide-related risks, Canada adopted the Pest Control Products Act (PCPA). The Pest Management Regulatory Agency (PMRA; http://www.hc-sc.gc.ca/ahc-asc/branch-dirgen/pmra-arla/index-eng.php) is responsible for administering the Act. A pesticide product label indicates the class designation (domestic, commercial, agricultural), the potential risks to human health and the environment, and the conditions and restrictions pertaining to product use. Compliance with the label directions and restrictions is mandatory. The provinces may also regulate the use of pesticides within their respective territory. For more information, consult the PMRA database at the following address: http://pr-rp.pmra-arla.gc.ca/portal/page?_pageid=34,17551&_dad=portal&_schema=PORTAL
5. Stages in an integrated disease management program
Prevention is the basis of integrated management programs for the black stem borer. Populations increase a few years after natural disasters. All measures to prevent wood from being left on the ground help to decrease the intensity of attacks by the black stem borer.
At the stand, plantation or nursery level:
- Cut down affected trees and rapidly remove wood. Favour harvests in fall or winter and process logs quickly (Katovich 2004).
- Wood should be piled outside the forest in a dry, sunny location.
- Where permitted, spraying piles very early in spring with chlorpyrifos-based products may prevent attack. Note that, in Canada, this product is not registered for use against the black stem borer.
- Sanitation cutting can be considered for affected stands or plantations. Wood from sanitation cutting should be burned or removed from the forest.
- In nurseries and plantations, a contact insecticide can be sprayed but treatment must be synchronized with the swelling of buds, be repeated and be carried out using persistent products. The emergence of the next generation after the initial attack occurs on average 54 days later so an additional spraying is required (Oliver and Mannion 2001).For ornamental trees, to prevent attacks, measures to restore vigour should be implemented. If needed, a permethrine insecticide can be sprayed on the bole of trees that need to be protected.
- [Anomyme]. 2000. Service phytosanitaire d'observation et d'information (SPOI). Le bostryche noir du Japon (Xylosandrus germanus). Bilan de la situation au printemps 2000. Complément du Bulletin SPOI publié en août 1991.http://www.wsl.ch/forest/wus/pbmd/artikel/snubof.html consulté le 25 février 2009.
- Graf, E. and Manser, P. 1996. The black timber bark beetle Xylosandrus germanus in Switzerland. / Der Schwarze Nutzholzborkenkäfer Xylosandrus germanus in der Schweiz. Holz-Zentralblatt 122: 454-454, 456. CAB Abstracts, EBSCOhost (accessed February 24, 2009).
- Insectes et maladies des forêts du Canada (IMFC). 2010. Pathologie forestière – Moyens de lutte. http://imfc.cfl.scf.rncan.gc.ca/maladie-disease/pathol-fra.html consulté le 11 juin 2010.
- Katovich, S. 2004. Black walnut in a new century, proceedings of the 6th Walnut Council research symposium; 2004 July 25-28; Lafayette, IN. Gen. Tech. Rep. NC-243. http://www.ncrs.fs.fed.us/pubs/gtr/gtr_nc243/gtr_nc243_121.pdf consulté le 25 février 2009.
- Naito, H., Goto, M., Ogawa, N., Soma, Y. and Kawakami, F. 2003. Effects of methyl iodide on mortality of forest insect pests. Research Bulletin of the Plant Protection Service, Japan, no. 39: 1-6. CAB Abstracts, EBSCOhost (accessed February 26, 2009).
- Oliver, J.B. and Mannion, C.M. 2001. Ambrosia beetle (Coleoptera: Scolytidae) species attacking chestnut and captured in ethanol-baited traps in middle Tennessee. Environm. Entomol. 30: 909-918.
- Ranger, C.M.; Reding, M.E.; Oliver, J. and Schultz, P. 2009. Electrophysiological and Behavioral Responses of the Ambrosia Beetle, Xylosandrus germanus, to Repellent Formulations. National Entomological Society of America Annual Meeting, December 13-16, 2009, Indianapolis, Indiana.
- Whitehead, R. J.; Wagner, W. L.; Nader, J. A. 2008. Storing beetle-killed logs under snow to reduce losses after mountain pine beetle attack. Information Report FI-X-003 - Canadian Wood Fibre Centre, Canadian Forest Service, Victoria, 21 pp.
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