Knowing an Insect’s Life Cycle to Develop an IPM Strategy

March 20, 2009

Odette from Baltimore, MD writes in:

“I have a boxelder bug infestation. I removed the box elder tree in the back last fall, hoping they would go away, however, I as welcomed to my garden today with swarms of them again. for the past 2 seasons I have been fighting these bugs with sprays, which work, but they keep coming back because I may not have gotten them all. Now that I have removed the tree, will they go away? (I moved to this house 2 years ago – the previous owner complained about them but did not know that they came from the tree. can you help me here? what else can I do? Any help is appreciated. “

Odette this is an interesting discussion item. Without a quite a bit more detail, I don’t know how helpful I can be, but here are some items to get you started.

First, I don’t know what insects you’re dealing with. It is important to fully identify the pest in order to understand how its life cycle happens and what plants it uses for these cycles. Once you identify your pest fully, you will be better armed to create an integrated pest management program (IPM) for managing the issue. And, it’s critical to be sure the insect you consider a pest isn’t actually a beneficial!

It may be that you noticed the insect in the Box Elder, but it could be that it only spends part of its lifecycle there. It may spend, say, a nymph stage on another plant in your garden or in the soil, for instance. Or, it may only live in the Box Elder. Or, it may have only spent its adult phase in the Box Elder because the Elder was under stress (pests like to go for the most stressed plant in the garden first in many cases). Or, it may need the Elder for part of its life. So, I suggest you fully identify the pest (if you haven’t already) and work with an arborists or local horticulturist to understand its lifecycle requirements. That might help you know if it will come back.

Since you do mention that you’ve been spraying, I’m going to assume you already know exactly what pest you have and that it is a pest. Knowing which pest you have is critical to knowing what course of pest management to take. If you don’t  know the pest, your sprays may have been contributing to the problem. Sometimes pesticides are applied by the unknowing only to end up killing the beneficials that prey upon our pests. Once the beneficials are removed, the pests have that much more success overtaking our gardens.

One thing you don’t mention is any damage the pests did to the plant. Did they actually do anything to the tree or garden? Or did they just seem annoying in big buzzing swarms? Could it be that these were actually beneficial insects that might have been “swarming the tree” to attack another pest that you didn’t see? It’s a question to consider…

So, what to do?

Try to identify the insect, understand its lifecycle and preferred habitats during the life cycles. If you’re unable to do this yourself, try working with your local Master Gardener Extension office to start.

Thanks for writing in and keep having fun in the garden!

1 Comment

  1. Nice, concise discussion about the importance of doing the first 2 steps of IPM: 1) inspection, 2) identify, and then 3) treatment strategy. (Edited to remove commercial links.)

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