| |
The RAAT Approach to Grasshopper Control
6/19/2008
Michael Fisher
Area
Extension Agent (Livestock)
Colorado State University Extension
Golden
Plains Area |
 |
| I have provided this information to assist you
with making informed decisions. If you have questions about this article or
suggestions on making this or other articles better, please click on the
buttons below. |
|
|
|
A couple of months ago I wrote an article about grasshoppers. In
that article, I discussed the aggressive appetite that these little pests can
exhibit and visited with you about setting a schedule on your calendar to be
monitoring for grasshoppers on your rangelands. If you have not taken a count
yet, you might want to consider it. The grasshopper population is exploding in
some parts of Eastern Colorado. Remember that depending on the species of
grasshopper that you are dealing with, from as few as 3 to as many as 40
grasshoppers per square yard is the point when the economic threshold is
reached. In typical rangeland or pastures the economic threshold is often
considered to be 15 to 20 nymphs or 8 to 10 adults per square yard. In addition
to this, studies suggest that 80 to 104 pounds of grasshoppers will consume the
same amount of forage as what a 1250 pound cow will on a daily basis.
I
have been in range pastures this week where the populations were in the 40+ per
square yard range. If you are in that situation you may be starting to consider
your options. With today's prices for fuel and pesticides it is not a happy
prospect. But if you are contemplating chemical grasshopper controls you might
want to do some research into the Reduced Agent and Area Treatment (RAAT)
approach.
Detailed information and guidelines for RAAT can be obtained
through the University of Wyoming or the USDA-ARS grasshopper website at
www.sidney.ars.usda.gov/grasshopper/. However, I will try to summarize the
concept. RAAT has two key elements. First is a reduction in the chemical's
application rate below the recommendations on the products label. (The
aforementioned website gives some product and rate suggestions.) Secondly, RAAT
uses swath spraying as opposed to blanket spraying. The swath spraying cuts
down on costs, promotes survival of insects that have a positive effect on your
rangelands, and allows grasshopper predators a safe harbor outside of the
application zone.
Research studies using ATV's to implement RAAT have
shown a 50 to 75 percent reduction in pesticide applied and a mortality rate
only 5 to 15 percent less than a conventional blanket application.
Additionally, the cost in this method was approximately 60 to 80 percent that
of having an aerial blanket application. RAAT research has also been conducted
using airplanes to do the applications. The aerial methods chemical reductions
and mortality rates were similar to that of the ATV studies. In some research
cases, the aerial RAAT application costs have been reduced by as much as
two-thirds from the cost of a blanket application.
Along with RAAT
guidelines, the previously mentioned website offers a couple of free,
downloadable software programs that a rancher can use to help him/her determine
when and how to best manage a grasshopper outbreak. These programs will allow
you to enter data based on your own operation (such as grasshopper counts from
your location) and receive research-based advice that relates directly towards
your current conditions.
If you have not already done so, make an
asserted effort to check for grasshoppers on your operation. As the growing
season moves on, be observant and if you start seeing a lot of grasshoppers
tell your neighbors, your Pest District Supervisor, your Extension Agent, or
your NRCS Range Specialist. Communication is one of the real keys to
controlling a major grasshopper problem.
Image of Grasshopper near
Burlington, Colorado |
Grasshopper damage near Burlington,
Colorado |
Grasshopper counting near
Burlington, Colorado |
|
|
Page Created and Maintained by: Perry D. Brewer, Area
Extension Agent (Technology Education/Youth)
6/20/2008 |
|
|
