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Causes and treatment of pesticide drift

What goes around comes
around—especially this time of year. 
Applying pesticides to crops is inevitable to keep insects, weeds and
disease at bay.  But pesticide
drift is not so predictable, as factors like temperature, wind conditions and
pesticide droplet size can all contribute to particles drifting from their
target. And if you think chemical drift will only affect your crop yield, you
are wrong.

Both pesticide applicators and their
neighbors are at risk for a slew of negative effects of pesticide drift. According
to Michelle Wiesbrook, University of Illinois pesticide safety educator, this
is the most important time of year to form good relationships with your

The UI Plant Clinic
diagnosticians have taken in an above average number of chemically injured
plants this season, a trend that can be offset by simple neighborly
communication. Whether you are an applicator, a grower or a neighbor of either,
the UI Extension Department of Agriculture suggests thinking about pesticide
drift from the other’s viewpoint.

“Growers don’t want their
pesticide products to land on your plants any more than you do,” Wiesbrook says.

Risks to Pesticide Applicators


As an applicator, the obvious
side effect of pesticide drift is a potential decrease in yield due to your
crop not getting the full amount of pesticide it requires. But a secondary risk
has a more blatant price tag: some instances of pesticide drift that severely
damage neighbor’s property can be legally filed.  Penalties for a violation of pesticide application range
from warning letters to monetary fines of $750 to $10,000, higher insurance
premiums, a damaged reputation in the business and revocation of the
applicator’s license.

Pesticide drift has the
potential of environmental consequences that should be of concern to
applicators and growers of all crops. 
For example, plants that have been unintentionally exposed to an
insecticide yet rely on bees for pollination, can have disastrous results for
both bees and plants, according to the UI Department of Agriculture’s website.  If pesticide residue and human exposure
due to pesticide drift is an increasing problem, the EPA may choose to limit or
eliminate that pesticide’s registration. 
Careless pesticide applicators can lose useful pest control tools for
the entire agriculture industry.


Drift-Reducing Practices

  • Choose equipment and nozzles with the correct droplet spectrum and pressure range.
  • When
    pesticide labels give a droplet size spectrum, choose the larger droplet size
    and higher application rate to better stay in your target.

  • Keep
    the spray boom height set only high enough to provide adequate nozzle pattern

  • Think about updating
    your equipment to include air assist sprayers, electrostatics and automatic
    rate controllers.

  • Avoid
    applications in winds over 10 mph and windless days.  However, this isn’t always possible, so consider wind
    direction and distance of neighboring areas as well.

  • Avoid spraying during
    the heat of the day when evaporation is more likely. Using pesticides that
    aren’t as volatile will help.

  • Choose
    low-volatility formulas that have less impact on neighboring crops and the
    environment. Amine formulations are best.

  • Use additives that
    reduce droplet size sparingly.

Risks to neighbors of pesticide applicators

Perhaps specialty growers have
the most to lose with pesticide drift. 
Products like fruit and flowers in which appearance is important can
have entire crops wiped out from small amounts of pesticides. Specialty crops
also require more hand labor than conventional crops, increasing the risk of
pesticide exposure and illness.

Similarly, organic crops have a
large investment in attaining certification by keeping their fields
pesticide-free for a consecutive three years.  While the presence of pesticide residue alone doesn’t
automatically void the grower’s organic certification, any carry-over damage to
the next growing season could. 
This is especially true for organic livestock being fed silage
containing pesticide residue.

Neighbors of crop producers
have lawns, gardens and their families to keep protected from pesticide
drift.  “If you are concerned about
the health of your plants or that of your family, share your concerns [with neighbor
producers],” Wiesbrook said.  “If
you know ‘what’ will be sprayed ‘when,’ you can plan accordingly by covering
your garden with old blankets, making sure the windows are shut, or keeping the
kids out of the yard during that time.”

What to do if you suspect pesticide drift


If you suspect your plants are
chemically injured, first compare them with another plant database like the UI’s
herbicide injury website (


General symptoms of pesticide injury include
plants, leaf discoloration, spotting, twisting, and slow plant death. 

Will your plants die? “That is
the million-dollar question,” Wiesbrook said.  The type and amount of chemical your plant was subjected to,
as well as the time of year and growth stage, all influence the resiliency of
your plants.

Wiesbrook suggests talking to
your neighbors about the timing of pesticide application with decline in health
of your plants, weather conditions at the time they applied and so forth.  Filing a complaint with your local Department
of Agriculture should be the last resort if an applicator is not willing to
reimburse your losses.

If you believe that you have been exposed
to pesticide spray or dust drift and have health-related questions, you should
contact your physician, local poison control center, or health department for
assistance. You can also contact the National Pesticide Information Center (NPIC).

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