What is “Integrated Pest Management”?
You may or may not have heard the term “Integrated Pest Management” (IPM) lately. It’s a newer approach to invasive species management that uses a multi-pronged approach to controlling infestations, instead of relying on one method for all infestations. It’s an attempt to move away from too much wholesale herbicide application and move toward using an appropriate action for whatever the problem may be. It is also an attempt to increase the efficiency of pest management, ensuring actions taken are effective and meet the goals of your organization or agency.
IPM is a decision-making process more than a treatment recommendation (although treatment recommendations are part of the process). It involves the following:
Set an action threshold:
How bad does the infestation need to be before you take action? The answer could easily be “A single plant.” but could also be “Only plants near or in these priority areas” or “When the infestation approaches this size”. It could be “when the infestation becomes an economic burden”, or “when the infestation approaches my property”. Determining when you should take action against the species is a good first step toward having an efficient pest management strategy.
Monitor and Identify Pests:
You’ve determined when you’re going to take action, now you need to determine where action should be taken. This could be as simple as keeping an eye on your fencerow every few weeks, or as complicated as monitoring hundreds of acres regularly for several species. This step will also determine what pests are likely to be problematic; you may have no Japanese knotweed on your radar at all, so sending a crew out to spray for Japanese knotweed would be a needless expense.
Before you start a treatment, you may be able to take preventative measures to keep infestations from entering your lands. This can include rotating crops, using rootstocks free from pests, ensuring the lands you’re interested in are not disturbed, or reaching out to people about cleaning their gear and clothing after recreating in or near invasive species. All this early effort, which isn’t especially expensive or laborious, can save you time and energy spent on removing invasive species in the future.
You’ve determined your action threshold, have found an infestation that exceeds your action threshold, and preventative measures have failed. Now, you need to determine the most effective control method. This is where using manual, mechanical, chemical and biological controls, either in concert or separately, comes into play. To make the appropriate decision, you use the least risky, but also most effective, control method available. This might be a mechanical control, say for Autumn olive, but using mechanical control for Japanese knotweed or purple loosestrife may be inefficient, expensive and difficult.
It is sometimes recommended to use the least risky control first, and then move on to targeted chemical spraying. However, widespread research can often tell you what size or severity of infestation will require herbicide, so using that information in conjunction with weighing the risks can save time in your decision-making process.
The last resort of any control should be broadcast spraying; avoiding broadcast spraying until all other methods have been tried is recommended.
Our beetle releases are part of an integrated pest management plan; the sites we released them at were above our action threshold, and were highly risky to treat with pesticides. The beetle populations will reduce the risk of contamination of water or injury to our spray contractor, even though they will take more time to control the loosestrife. In other locations, we have decided to use targeted herbicide application, as the sites are accessible and mechanical removal is not viable. In other locations, we have not taken action because our action threshold has not been met (either the location is not as high a priority, or the population is too small).
Careful decision-making in invasive plant management can reap you the rewards of less risk, less expense and more effective control than jumping into a project head-first.