Cedar Valley Arboretum & Botanic Gardens

Hormones and Gypsy Moths

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When I think of hormones, I tend to first think of my awkward teenage years – definitely not insects.  But the two terms keep popping up together and it’s actually a fascinating study.  Why should we gardeners care about hormones?  Because it is an excellent organic control method.

Let’s start by defining a few terms.  Hormones are chemical compounds produced and used internally to affect the cells in another part of the organism.  Pheromones, on the other hand, are hormones used externally.  This is the type of hormones we are interested in as gardeners.  (The chemistry of both is very complex, but for simplicity’s sake we’ll keep definitions short and to the point – science was never my strong suit!)

Insects use pheromones to communicate every day.  While there are many different types, alarm pheromones, food trail pheromones (think ants) and sex pheromones are the most common.  And by manipulating sex pheromones, we can naturally control insect populations by disrupting reproduction.

Tree defoliation occurs with the immature stage of the gypsy moth. We have not had infestation (thankfully!) as far west as the Arboretum so I had to find a photo online. Photo from the U.S. Forest Services website, www. http://www.fs.fed.us.

As this information is sinking in, take a moment to read this recent article from the Des Moines Register about Iowa’s gypsy moth infestation:  http://www.desmoinesregister.com/apps/pbcs.dll/article?AID=/201101280405/NEWS/101280335.

In the case of gypsy moths, the female moth secretes a sex pheromone when she is ready to reproduce.   The male moth catches and follows that signal until he finds the female.  According to the article, authorities plan to control the gypsy moth population in Iowa (therefore hopefully stopping damage to hundreds of species of trees) by releasing a synthetic sex pheromone into the air during peak reproduction time in late June.  Male gypsy moths will not be able to find the female gypsy moths because her sex pheromone will get lost in the overpowering synthetic pheromone surrounding the male.

Can’t you just imagine that poor guy flying around in circles looking for his girl?  And we thought the dating scene was rough as humans!

See you in the gardens.



Written by cedarvalleyarboretum

February 2, 2011 at 12:23 am

Posted in Uncategorized

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