Sunday, January 27, 2008

ISA HK/China --- Introduction to Integrated Pest Management (IPM)

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Dear Station Members,

The attached article is extracted from the Arborist News Dec 2007 edition. Conventional landscape managers & horticulturists may not like the information contained but this article was written by a professor in an US institute after years of research. It was also published in an international journal circulated to at least 57 countries around the world. So, there must be something to it.

Pest Management is an important job of landscape maintenance anywhere in the world. After all, landscape is created for aesthetic & pleasure besides a varieties of functions. If ruined by pests, all the money devoted into it would be in vain. This article gave an insight to the current international practice in pest management as compared to what we are used to in our part of the world. It also gave reasons & suggestions for what to do & what not to do.

When the Station Manager first started learning about pest management (or better calling it pest control then) in the 1980's, he studied it through conventional horticulture describing blanket chemical spray & pest eradication. The only objective of these measures appeared to be killing every pest suspected without thinking too much of non-targeting organisms, or maybe it was simply bad luck to any of them. Time & care were set at making the best possible chemical solution to target the organisms. Preventive & regular spray were the answer to a 'clean & hygienic' growing environment, whether inside or outside a greenhouse. Any kill would be regarded as a success & a reward.

Deviation from this traditional practice has evolved from research over the years in the west. It was discovered that a complete eradication of all organisms would lead to a stronger (or even more resistant) outbreak of pest emergence after regular spraying which would also pollute the environment. Measures were then looked into the holistic approach & it would be the suppression of the pest population rather than total eradication, coupling with a study on abiotic effects & client's expectation to evolve the theory of Plant Health Care (PHC) which incorporates the Integrated Pest Management (IPM) concept for managing landscape pests. It was also discovered that any treatment should be entire rather than individual, since the mixture of plants interact with one another in the landscape.

This new theory of PHC & IPM has since then become popular in western countries. However, the wind of change did not seem to come across strongly to our part of the world. Blanket spray & intentional chemical mixtures still appear to be the answer to pest management in our city landscape, partly becasue it is easier to administer & less training is required for the operating personnel. Then when our pest problem would become more resistant to treatment, the landscape managers would look for a stronger & more powerful spray. Hence the vicious cycle continues.

This Station is not aware of PHC or IPM being practised in a working level anywhere in our territory so far, except at ETF which is under the control of the Station Manager himself. Both PHC & IPM require knowledge & experience to carry out, not just theories & description from books. This Station is not aware of either knowledge is being offered properly & publicly anywhere in any institute in HK so far.

Modern Arboriculture is founded on the principles of PHC. If PHC is not good enough for HK, then western countries may be wasting their time to research into the topic to tell the world. Then maybe HK should carry on their regular chemical spray intentionally.

Which way should we look at now then & for why ...?

best regards,

Sammy Au
Station Manager

The ISA Mission - Through research, technology, and education, promote the professional practice of arboriculture and foster a greater public awareness of the benefits of trees. (

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