NEIGHBORHOOD GARDEN FOR JUNE 16, 2007
WHAT IS THE DIFFERENCE BETWEEN
A PESTICIDE AND AN INSECTICIDE?
BY GEORGE EDGAR
I wrote this
article in December of 2005. Since its publication I have had lots of
questions about pesticides, which leads me to believe that many
gardeners and homeowners do not know what an insecticide is, what a
fungicide is, what a herbicide is, and what are miticides. Or when does
one use one or the other, and are there other alternatives to
controlling a pest. Therefore, I am running this again.
insecticides, (as well as fungicides, miticides, and herbicides) are
pesticides, but not all pesticides are insecticides. Thus, Sevin, Eight,
Isotox, and Malathion, are common insecticides, but will not control a
plant disease, or kill a weed. A fungicide is also a pesticide and used
to control “spots and rots” or plant diseases. Herbicides are
pesticides and used for killing or preventing weeds, but does not kill
insects or control diseases. Before buying a pesticide it is
important to identify what the pest is. And if an insect,
what insect is causing the damage, or if a disease, what the disease is
and what caused it. If a weed, what kind of weed. Do
not apply chemicals before proper diagnosis. Many symptoms
may look the same to an untrained eye. Also remember that a fertilizer
is not a pesticide and will not cure a plant disease or plant injury
from an insect, but may make the problem worse.
PESTICIDE according to the “Federal Insecticide, Fungicide, and
Rodenticide Act” is defined as “any substance or mixture of
substances intended for preventing, destroying, repelling, or mitigating
any insects, rodents, nematodes, fungi, or weeds, or any other forms of
life declared to be pests.”
act also requires certain information be on the label.
Be sure and read the label to make sure the chemical you are
using is ok for use on your plant.
If the name of your plant is not on the label, don’t use it.
Also the label should tell you if it will control the problem you
have, what the proper dosage is, and how often you can apply it. READ
THE LABEL BEFORE USE!!!
pest is defined as anything that:
Competes for food or water,
Injures humans, animals, plants, or possessions,
Spreads disease, or
Annoys humans or domestic animals.
include but are not limited to:
Insecticides for the control of insects,
Fungicides for the control of plant diseases,
Herbicides for the control of weeds,
Rodenticides for control of rodents, and
Miticides for the control of mites.
are combinations. For example, most fruit tree sprays contain 2 insecticides
such as Malathion and Carbaryl (Sevin), and a fungicide such as Captan.
A fertilizer, such as Miracle-Gro is not a pesticide that will control
insects or diseases. If a
plant looks sick, don’t automatically apply a fertilizer.
This may stress a plant to grow rather than correct what is
wrong, and may make the problem worse. Get a proper diagnosis.
When taking a
sample to the garden center or the Extension Office for a diagnosis,
please take a big enough sample. One or two leaves or a few blades of
grass doesn’t work. For a
tree or shrub cut off about 10 to 12 inches minimum. For grass a piece of sod about 8 inches square is necessary.
Take the sod from the edge of the problem and include some brown
and some green.
In applying the
principles of Integrated Pest Management (IPM), one should look at all
other options before applying a chemical. These include
Planting a pest resistant variety,
Using biological controls,
Cultural practices such as mulch and crop rotation,
Mechanical controls such as traps, hand removal, and sticky
Sanitation, such as cleaning up your garden in the fall with
proper disposal of all waste.
Examples of good IPM
Clean up your iris bed every fall as iris borer can overwinter in
Overplant with a blend of disease resistant varieties of grass to
control summer patch or brown patch in lawns.
Rotate where tomatoes are planted to control tomato blight as the
disease spores overwinter in the soil. Also do not water overhead if
possible so the blight spores don’t splash up on the lower leaves.
When my tomatoes are about 3 to 4 feet high I take off the lower
8 to 10 inches of branches so I have good airflow.
This helps to prevent blight and powdery mildew.
Use mulch (wood chips or shredded hardwood) under roses to help
control black spot which also lives in the soil and can splash up on the
lower leaves and infect the bush.
Cover young squash, melon, watermelon, and cucumber plants with
row cover to prevent the squash vine borer from laying eggs on or near
the base of the plant. Uncover
when plant starts to bloom so beneficial insects can pollinate the
flower. Row cover can be purchased at most garden centers or go to a
fabric store and buy “underlayment”.
It looks almost like cheesecloth, so buy the lightest weight
material. If you do get squash bugs, pick them off and look for eggs on
the underside of the leaves.
Again, before buying
a pesticide (spray, dust, or granule) it is important to identify what
the pest is, and if an insect, what insect is causing the damage, or if
a disease, what the disease is and what caused it. Do
not apply chemicals or fertilizer before proper diagnosis.
to Larry D. Schulze, Pesticide Education Specialist, University of
Nebraska Cooperative Extension, for permission to use material that he
presents to our Lancaster County Master Gardeners most every year. For
more information you can go to his website at http://PestEd.unl.edu.
(G), Educational Circulars (EC), and NebFacts (NF) are available on the
internet. Go to http://ianrhome.unl.edu/search.
In the top box scroll down to “Extension”. In the bottom box type in
the name of the plant, or the subject, or the name of the pest (insect
or disease or weed or rodent), or the number of the publication desired.