Putting organic mulch in your landscape is one of the
most beneficial activities your can do for your trees and shrubs. But recent
e-mails circulating over the Internet warn that cheap termite laden mulch
will soon be popping up at our corner garden center causing spread of the
dreaded Formosan subterranean termite. The story goes on to describe most of
the trees destroyed in hurricane Katrina as infested with Formosan termites
which will be chipped and bagged along with the wood and spread by unknowing
or unscrupulous retailers.
Although termites are a constant concern in
Florida, these stories contain more hysteria than truth. Termites are social
insects with a queen and distinct social order of workers and soldiers.
According to a University of Florida entomologist,
the termites in infested wood do not survive the chipping process well.
Chipping and subsequent bagging and transport are very disruptive for
individual termites that survive. And those few termites that might show up
in a bag of mulch will be unable to establish a queen and the social
structure to start a new colony. These individual termites will eventually
die even if adequate food is available.
Subterranean termites will die if exposed
to air and sunshine. The fluffy, airy texture of organic mulch is not the
most desirable environment where termites can survive and flourish. Termites
prefer to be inside a solid piece of wood and subterranean termites
including the Formosan termite must regularly return to the soil for
moisture. Mulch is usually too airy and fragmented to be desirable habitat.
And finally,
last October the Louisiana Dept. of Agriculture imposed a quarantine on the
areas with Formosan termites to prevent the spread of the Formosan
subterranean termites to locations not now infested.
So it is
unlikely first that termites and especially Formosan subterranean termites
will be in mulch you purchase. And even if some termites were to make it as
far as the bagged mulch you have purchased for your landscape, it is even
more unlikely that those termites would be able to create a viable colony.
If you are still
concerned, lay the plastic bags of mulch in the sun for a day or two turning
the bag every few hours. The heat buildup inside the bag will cook any
remaining termites.
Organic mulch is
still one of the best and least expensive landscape improvements you can
make to your yard. Mulch gradually breaks down and mixes with the soil to
create a humus-rich organic layer much like the soil in a forest. Of course
you should avoid using weed mats that create a physical barrier between the
soil and the mulch. Weed mats, in my opinion, do not work well at preventing
weeds which can grow on top of the mat or through the mat. Place a thin
layer (about two inches) of mulch over the soil.
Some homeowners
may be considering switching from organic mulch to mineral (stone) mulch to
avoid termites. But using stone mulch is really not helping prevent termites
which are attracted by the moist soil conditions created by mulch rather
than the food value of the mulch. That means termites can be found under
stone mulch as readily as under organic mulch. If you are concerned about
placing mulch too close to your home, the recommendation is to keep all
mulch, whether stone or organic, back about 12 inches from the foundation.
Bare-dry soil next to the foundation along with the appropriate termaticide
barrier is still your best defense against termites. Also, keep sprinkler
irrigation sprays away from the foundation. Point sprinklers away from the
house, not toward or along the house. And divert the condensation trickle
from your air conditioner away from the house foundation.
