Hi Welcome the Grower Pesticide Safety
Course. This is Chapter 7 Pesticides and the Environment. Chapter 7 starts on
page 79 of the manual. There are 23 slides in this presentation so it will
take us about 15 minutes to review. So let’s get started. What will I learn? At
the end of this lesson you should be ready to, identify and explain the four
factors that determine environmental risk, describe processes that affect the
fate of pesticides in the environment, describe actions you can take to prevent
pesticide contamination of air, water, and soil, and describe actions you can take
to protect bees from pesticide poisoning. Let’s start with protecting air, water,
and soil. How you use pesticides can affect the environment. You need to
follow the label’s environmental precautions, and those will be under the
precaution section on the pesticide label. A label will state the ways that
the pesticide is harmful to the environment, and then give you directions
on how to prevent harm. Directions could include such things as: “Leave a 1 meter
buffer zone between the treated area and water” “Don’t apply to areas with steep
slopes” “Don’t apply next to areas when bees are present”. These are all examples
of precaution statements. Now let’s look at the environmental risk. Each time you
use a pesticide there is some risk to the environment and the degree of risk
depends on four risk factors: persistence, mobility, non-target toxicity, and volume
of use. Now let’s look at the each one of these a little bit more. Persistence — how
long does the pesticide remain active in the environment. And we’ve had some
history on persistent pesticides. Examples include DDT, picloram and
atrazine. Mobility — this is how easily does the pesticide move away
from the site, and it could move through air, water, or soil. Non-target toxicity —
how toxic is the pesticide to species that are not the pests that you’re
trying to manage. Volume of use — how much of the pesticide is being used across
Ontario, used on your farm, overall. So we put all these four factors together, we
have an equation that represents environmental risk. Persistence, mobility,
non-target toxicity, and volume of use. The lower any one of these factors, the
lower the risk. Pesticide fate–what happens to a pesticide after it is
applied. A pesticide’s properties influence its fate, that is how it reacts in the
air, in the water, sunlight, and soil, and how it reacts with
microorganisms, plants or animals. So it all depends on the pesticide’s properties. The physical and chemical properties — we
can list those as, degradation, bio-accumulation, bio-magnification, and
adsorption, absorption, and volatility. All physical and chemical properties of the
pesticide. The natural processes that will affect the fate of the pesticide,
that includes, spray drift, vapour drift, surface runoff, leaching, soil erosion. And
we’ll look into each one of these in the next few slides. Degradation is the
breakdown of pesticides into simpler and less toxic products. Pesticides are
broken down through three processes: microbial degradation – the breakdown of
pesticides by microorganisms that live in the soil and
use of the pesticide as a food source; chemical degradation – the chemical
reactions that occur, pesticides and the chemicals in the environment such as
with water; and photo degradation – is the breakdown of pesticides by sunlight.
And pesticides react differently when exposed to sunlight. Sometimes they
break down rapidly and sometimes they break down so rapidly they have to be
incorporated in the soil after you apply it to prevent some of the photo degradation
that might happen. Here we go again. Microbial degradation – microorganisms use
the pesticide as food. Chemical degradation – chemical reactions break
down the pesticide. Photo degradation – sunlight breaks down the pesticide. The
rate of break down is measured by half-life. DDT and picloram are
persistent and have half lives longer than a year. 2, 4-D and
atrazine are moderately persistent with half-lives of two to three weeks. So
half-life, again, measures the rate of degradation, the time it takes for one
half of the pesticide to break down when it was released into the environment. Now
let’s go on to bioaccumulation. Some pesticides have the ability to build up
in fatty tissues in the body. These pesticides continue to build up after
each exposure and as they accumulate, the pesticides become increasingly harmful
to your health. So here we have for rat number one at the top, he has filled up,
some pesticides are staying in his body. He gets some more exposure, more
pesticides accumulate, and eventually ending in death. Biomagnification –
this is the ability of some pesticides to build up in the food chain. So we have
little microorganisms that are contaminated with
pesticides, they get eaten by fish, and then the bigger fish eat the smaller fish, and
then the ducks or loons eat the fish that are contaminated, so it’s the
movement of the pesticides indirectly through other food sources. Toxaphene is
a pesticide, an insecticide actually, that is extremely persistent and it
bioaccumulates in fish. It was removed from use in
Canada in 1974. Our next term is adsorption, with a “d” and this is the
binding of pesticides to soil particles another matter. So this is similar to paperclips
sticking to a magnet. Sometimes pesticides bind to soil particles.
Absorption — and this is the movement of pesticides into plants or animals and
structures such as soil and wood. And similar to water being absorbed up by a
sponge, some pesticides will be absorbed. Some pesticides are more susceptible to
being a volatile pesticide. Pesticides change from liquids or solids into
vapours. Things you can’t see when exposed to moisture, heat, and air. The
volatility increases when temperatures are high and droplets are small. Examples
are 2,4-D and dicamba. They’re very volatile and will injure
sensitive crops. So it’s best if you know if you can pick a low volatility
formulation. Choose low volatile product. Now let’s talk about dicamba a little
bit more. Dicamba products have been reformulated to reduce their
volatilization. 1967 dicamba was sold as a DMA formulation salt, Banvel. In
1983, dicamba was sold as a DGA formulation less volatile called
Banvel II. Then in 2017, we have dicamba sold as
XtendiMax with VaporGrip, a DGA salt with encapsulation and Engenia, a BAPMA salt, another type of formulation, also to reduce volatility. So
we have made strides and trying to reduce some of these products volatility
by the formulation and the chemistry used to make them. So then if you have a
choice it’s best to use and buy the product with the least volatility. If you
are spraying 2,4-D or dicamba next to sensitive crops, it’s very important you
try to minimize this drift. So these crops are sensitive to 2,4-D and dicamba: grapes, sweet potato, tobacco, pepper, tomato, watermelon, also cantaloupe,
cucumber, peach, peanut, squash, broccoli, cabbage, kale, mustard, and turnip. So again
be very careful. Make sure that you are spraying so that the wind is blowing
away from a sensitive crop. How do pesticides move with wind and water? Now
we have drift, surface runoff, leaching, and soil erosion as the four key factors.
Let’s talk a bit about drift. Vapour drift occurs when the wind moves
pesticide vapors from the site of application. We’ve talked that about that
a bit under volatility. And spray drift occurs when the wind moves spray
droplets from the site of application. It’s also called particle drift. Surface
runoff – definition – pesticides move with water over the soil surface. Pesticides
move with water when they dissolve in water so are soluble or they might
bind, be adsorbed, to soil particles that move in the water. So that’s
happening with soil erosion. Factors that affect runoff: slope of
the land, you can imagine the higher, greater the slope, more runoff, the soil
type and texture, moisture content of the soil, crop residues on the soil surface
would prevent some soil erosion, and rains or irrigation that happens after
application that’s going to put you in a place where the pesticide will move off
with the rain with the surface runoff. Reduce surface runoff. There are some
things we can do. We can watch the weather. We can make sure we don’t apply
pesticides if rain is forecast within the next 12 hours. Don’t irrigate
immediately after pesticide application. Use adjuvants to stick the pesticide to
plant surfaces, especially if that’s recommended on the pesticide label. Do
take a look and then use no-till or minimum tillage to reduce that soil
erosion. Now we need to talk about leaching. Leaching occurs when pesticides
are dissolved in water and they move through the soil. The movement may be
downward, and may be upward, to the side. Pesticides move into groundwater or to
tile drains going with the effect of leaching. Pesticides are more likely to
leach of course, through soils that are sandy, or have a low water holding
capacity. And 2, when pesticides are persistent or soluble in water. Again
we’re going to have more leaching at those times. So when we’re thinking about
applying of pesticides, we have to take some of these things into consideration,
and we can take actions to protect water. So Ontario has two laws: use an anti
backflow device when you fill your equipment so we don’t want any backflow
going into our water system, and another law, never wash equipment near surface
water, ponds, streams or creeks. So those are two things
we can do and those are in the Pesticides Act and Regulation 63 09. Recently we’ve
had Source Protection Plans in Ontario. So Ontario now has 22 Source Protection
Plans and the plans of actions that you must take to protect municipal drinking
water. So this will depend on the watershed, and your municipality will
know what watershed you’re in. You may need to use specific buffer zones in
addition to those on the label, or store and mix pesticides at a specific
distance from a well or drinking water intake. Again it’s your municipality you
should contact. Now you can go online. Look for the “interactive source water
protection map” and going onto that website, you can put in your address and
you can see what restrictions for protection of water would be for your
municipality. Protecting bees. Alright. So we know that pesticides are harmful to
people, we know that pesticides are found harmful to bees, as well beneficial
insects, fish, birds, wildlife. And bees are important because they pollinate our
tree fruits, small fruits, legumes and other vegetables. They
produce honey for us and they can be poisoned by pesticides. They can be a
poisoned through a direct exposure or indirect exposure such as if the pollen
they collect and store in the hive is contaminated with the pesticide. So
there’s somethings we can do. Do not apply pesticides while fruit trees are
in bloom. Follow the label directions to protect bees. Apply pesticides after 8
p.m. when bees are not active, they’ve gone back to the hive. And your
neighbouring beekeepers. Tell your neighbouring beekeepers when you plan to
apply pesticides or when you plan to plant treated seeds. Reducing risk to pollinators from
treated seed. In the spring of 2012 and 2013,
residues of neonicotinoid insecticides neonics were found in 70 to 75% of
dead bee samples that season. The neonic active ingredients include imidacloprid
thiamethoxam and clothianidin. Anyway, the neonic treated seeds include seeds treated with products such as
Poncho 600 FS seed treatment, Cruiser 5 SF seed treatment, Stress Shield 600, Acceleron iX 409 insecticide seed treatment, and Cruiser Max Beans Seed Treatment. So those are
some of the products that we now have to have further pest management protocols
that we have to follow when we’re using neonic treated seeds in Ontario. We want to
reduce our risk to pollinators from treated seeds. So bees could have been
exposed in the dust generated during the planting of the neonicotinoid treated
corn or soybean seed. So you want to adjust your planter to reduce the dust.
Mount air intakes for vacuum meters up high so that field dust does not enter
the planter. Use dust reducing fluency agent, and control the flowering weeds and
plants around the field so bees are not in the area. And of course, we have the
IPM Course for Corn and Soybeans and we now need to be certified to buy and use
the neonicotinoid treated seeds for corn and soybeans. Here’s a learning
activity for you. This is our last slide and just a summary as you’re thinking
about your farm as your environment. In the first box, I would like you to list —
these are my environmental risks and concerns. So things that might be on
your farm, a creek, a sensitive area, slope of the ground. And
on the other side of the page, we can write in another box. I will take these
steps to minimize risks – minimize the risk. So think about what you might be
able to do when you’re applying pesticides to make sure that you’re
reducing risks to the environment, to the water, air, and the soil.