Thursday, June 21, 2012

What acorns and invasive plants have to do with ticks and Lyme Disease

Several years ago, I wrote a post about the abundance of acorns in the area, entitled "Abundant Acorns a Harbinger of Good Things to Come?"

Well, apparently they were a harbinger of BAD things to come, in the form of ticks.

I’ve read comments on several local garden sites recently about people seeing a lot of ticks in their gardens and apparently acorns may be partly to blame for the problem.

An article in the Summer edition of Maryland Home and Garden blames part of the problem on the huge numbers of acorns that we have had over the last few years.

Here are a few excerpts that explain how the boom and bust in acorns have led to more ticks in our yards:
The article goes on to say that certain invasive PLANT species are known to attract and harbor these dangerous pests:

The article goes on to say that certain native plant species may be adding to the problem: 
According to a New York Times article on December 2, 2011, the boom and bust cycle in acorn production over the past two years will likely result in a very high incidence of Lyme Disease in areas with lots of oak trees in 2012. Richard S. Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, N.Y., said, “We expect 2012 to be the worst year for Lyme disease risk ever.”

Bumper crops of acorns, like the one we saw in 2010, provide a huge source of food for many mammal species, including the field mouse. This surplus in food led to a population explosion in field mice in the summer of 2011. Because the 2011 acorn crop was very small and unable to support the bigger population, field mouse numbers are expected to crash this year.

This food boom and bust cycle trickles down to other species, like deer ticks—also known as blacklegged ticks or bear ticks. Just as more acorns mean more mice, more mice mean more ticks. When the mouse population crashes, ticks will be in search of other sources of a blood meal, including humans.

The number of tick bites on humans is therefore expected to increase, and the percentage of ticks infected with the Lyme disease bacteria is expected to be higher, leading to an overall increase in human cases of the disease.
The article goes on to say that certain invasive plants species can add to the problem:

One of the ways that humans help the disease thrive is through the spread of invasive species like Japanese barberry and bush—or Amur—honeysuckle. These plants create the perfect habitat for both ticks and their hosts by creating a thick layer of cool and moist undergrowth. Studies have shown that tick populations are 67% higher in barberry-infested areas, and that there are three times as many ticks infected with the Lyme disease bacteria than in areas with no barberry.

Lyme Disease is a serious health issue and the presence of ticks should not be taken lightly. For information about ticks and Lyme Disease, visit these resources:

Centers for Disease Control and Prevention: Lyme Disease
Lyme Disease: Montgomery County Website

Click here to download the Summer 2012 Edition of Maryland Home and Garden,

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