Southeastern U.S. Vegetable Crop Handbook - 2021 - 134

Registered Fungicides, Insecticides, And
Miticides For Vegetables
Recommendations of specific chemicals are based upon information
on the manufacturer's label and performance in a limited
number of trials. Because environmental conditions and methods
of application by growers may vary widely, performance of the
chemical will not always conform to the safety and pest control
standards indicated by experimental data.
Recommendations for the use of agricultural chemicals are
included in this publication as a convenience to the reader. The use
of brand names and any mention or listing of commercial products
or services in this publication does not imply endorsement by
Auburn University, Clemson University, Louisiana State University,
Mississippi State University, North Carolina State University,
Oklahoma State University, Texas A&M, University of Florida,
University of Georgia, University of Kentucky, University of Tennessee,
and Virginia Tech nor discrimination against similar products
or services not mentioned. Individuals who use agricultural
chemicals are responsible for ensuring that the intended use complies
with current regulations and conforms to the product label.
Be sure to obtain current information about usage regulations and
examine a current product label before applying any chemical. For
assistance, contact your local county Extension office.
BE SURE TO CHECK THE PRODUCT LABEL BEFORE USING
ANY PESTICIDE.
RESISTANCE MANAGEMENT AND THE
INSECTICIDE RESISTANCE ACTION COMMITTEE
(IRAC) CODES FOR
MODES OF ACTION OF INSECTICIDES
Many insecticides affect a particular chemical involved in the
function of an insect's nervous, digestive, respiratory, or other system.
Some broad-spectrum insecticides affect chemicals that occur
in many places within the insect and have a wide ranging effect on
the insect. Usually, these are older insecticides that have been in
use for many years. The chemicals that these insecticides affect are
often found in other animals as well. This can result in the insecticide
having undesirable effects on these other animals (non-target
effects). Also, non-target effects and persistence in nature have
contributed to concerns about these older insecticides.
Many new insecticides have been developed over the last
decade, specifically to minimize non-target effects and reduce persistence
in the environment compared to older insecticides. This
limited persistence in the environment also reduces the potential
for non-target effects. However, the primary means of reducing
non-target effects has been to make these newer insecticides very
specific for a particular chemical (usually an enzyme produced by
a single gene) found only in certain insects or groups of insects;
thus making the insecticide selective for a particular type of insect.
Unfortunately, there is a negative aspect to this specificity. Because
134
only one enzyme is affected, the natural process of mutation can
result in genetic modifications that alter the enzyme so that it is
unaffected by the insecticide. Insects possessing the modified gene
will not be affected by the particular insecticide. These insects will
reproduce and, in time with continued exposure to the insecticide,
will produce a population of insects that is resistant to the insecticide.
Since most of the new insecticides have been developed to be
very specific, resistance will develop much more quickly than with
previous insecticides.
Different insecticides affect different enzymes, and insecticides
are placed into classes based on which enzymes are affected.
These classes are called Modes of Action (MOA). Although insecticides
may have different names, they can have the same mode
of action and affect the same enzyme or system. It is the mode of
action to which the insect will become resistant. Because of this,
an insect management program MUST rotate the modes of action
of the insecticides used during the cropping cycle. To prevent the
development of resistance, it is important not to apply insecticides
with the same mode of action to successive generations of the
same insect. Insect development time can vary by species and environmental
conditions, and generations often overlap in the field;
proper scouting is necessary to determine when modes of action
should be rotated. To make it easier to determine an insecticide's
mode of action, the IRAC has developed a numerical code with a
different number corresponding to each mode of action. New packaging
has been developed with a colored banner on the top of the
package and label giving the IRAC code. For example, the insecticide,
Movento®, has a new mode of action and the package says:
GROUP 23 INSECTICIDES
Growers can now easily identify the mode of action of a specific
insecticide. This will help them to plan their rotation of materials
to avoid rapid development of insecticide resistance and help
prolong the life of these important new crop protection materials
while providing adequate management of their pest problems.
More information about insecticide resistance and a concise chart
of all of the IRAC codes can be found at the website:
www.irac-online.org.
2021 Vegetable Crop Handbook for Southeastern United States
http://www.irac-online.org
Southeastern U.S. Vegetable Crop Handbook - 2021

Table of Contents for the Digital Edition of Southeastern U.S. Vegetable Crop Handbook - 2021
