Exposure Risk of Minnesota’s Farmland Wildlife to Agricultural Pesticides

Nicole Davros, Ph.D.

Upland Game Project Leader MN DNR Farmland Wildlife Populations & Research Group

Madelia, MN

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800P

he

asan

t H

arve

st (

1,0

00

s)

CRP Era, 1987-2007

Diversified Farming Era

Northern Bobwhite

population declines since mid-1960s

Breeding Bird Survey (BBS) Trends, 1966-2012 Sauer et al. 2014

Bobolink Dickcissel Red-winged

Blackbird

Similar declines in other

grassland-dependent birds

Breeding Bird Survey (BBS) Trends, 1966-2012 Sauer et al. 2014

Population declines in beneficial insects such as pollinators, too

These declines have mostly been attributed to grassland habitat loss & fragmentation that has resulted from agricultural intensification

But there’s increasing evidence that pesticides may also be important in explaining declines in

wildlife populations

• Pesticides are chemicals used to kill or control pests

• “Pesticide” is a broad term that includes: – Insecticides*, herbicides, fungicides, etc…

• Insecticides*are not always target-specific, and other plants & animals can be affected when exposed – Insects, spiders, mammals, birds, fish, amphibians, reptiles,

plants

A few definitions:

• Type of Application

– Contact: sprayed directly on plants for protection against pests

– Systemic: absorbed by the plant as it grows and then protects all plant parts

• Residual vs. Non-Residual

– Length of time that the insecticide remains in/on the plant or in the soil • Impacts the target species as well as non-target community of plants

& animals

• Affects withholding time, which is the minimum period that must elapse before plant product is safe for harvest or use

Insecticide impacts on wildlife may be:

• Direct

– Primary exposure • Breathing, skin contact, eating

– Secondary exposure • Eating another exposed animal

• Indirect

– Impacts to the animal’s habitat • Reduced food availability

• Reduced habitat cover

Jake Dingel, PA Game Commission

Two Wildlife/Insecticide Issues Currently Being Discussed in Minnesota

• Neonicotinoids

– aka “neonics”

• Soybean Aphid Insecticides

Neonicotinoids (aka “Neonics”)

• First introduced in early 1990s – Considered at time to be a “soft” pesticide that was safer than other

options

• Now used extensively – Use has tripled in last decade

– Nearly all corn and >50% of soybeans are treated with neonics

Neonicotinoids (aka “Neonics”)

• Seeds treated prior to planting – Systemic

• Absorbed into pollen & nectar, too

– Designed for early-season pests

Ian Grettenberger, Penn State

Treated seeds in blue & red

Untreated soybean & corn seeds

Neonicotinoids (aka “Neonics”)

• Work as neurotoxins – Disrupt the central nervous system

• Considered to be lower in toxicity to mammals

• Many types of neonics, including:

– Imidacloprid (Gaucho, Axcess)

– Thiamethoxam (Poncho, Acceleron)

– Clothianidin (Cruiser, Platinum)

– Dinotefuran

– Thiacloprid

– Acetamiprid

Neonicotinoids (aka “Neonics”)

• Potential exposure of non-target organisms

– Dust from planters during sowing

– Ingestion of spilled seed

– Persistence in soil • Only 2-20% of the chemical is absorbed by plant

• Remainder ends up in soil with half-life of 7 days to 6,931 days

http://seedworld.com/seed-treatment-saga/

Neonicotinoids (aka “Neonics”)

• Implicated in Colony Collapse Disorder (CCD) of bees and declines of many species of butterflies

– Cause/Causes of CCD still being identified but recent research suggests that neonics:

– Are directly toxic to bees

– Increases susceptibility to pathogens, which have also been implicated in CCD

• Also pose risks to:

– Birds

– Aquatic invertebrates

– Other beneficial insects • Predatory & parasitoid species

– Provide biological control of pest species

USDA-ARS/Scott Bauer

• Neonic seed treatments do not provide significant yield benefits in most contexts

• Must weigh the value of production of honey & other bee products as well as financial harm to beekeepers and other producers reliant on beneficial insects

Two Wildlife/Insecticide Issues Being Discussed in Minnesota

• Neonicotinoids

– aka “neonics”

• Soybean Aphid Insecticides

• Soybean aphids arrived in Minnesota in 2000

• Spread throughout farmland zone by 2001

Two commonly-used insecticides used to treat soybean fields infested with aphids:

– Lambda-cyhalothrin

• Broad-spectrum pyrethroid (neurotoxin)

• Tradenames include: Charge, Danger, Demand, Excaliber, Grenade, Hallmark, Icon, Karate, Kung-fu, Matador, Saber, Samurai, Sentinel, Warrior

– Chlorpyrifos

• Broad-spectrum organophosphate (neurotoxin)

• Tradenames include: Dursban, Govern, Lorsban, Pilot, Warhawk, Yuma

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

To be fair… A lot of chlorpyrifos was being used prior to the

arrival of aphids in MN

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2012&map=CHLORPYRIFOS&hilo=L&disp=Chlorpyrifos

In July 2014, the MN Dept. of Agriculture released voluntary BMPs in response to concerns over water quality and human health effects

UM Extension also released guidelines on how to scout for aphids and when to consider treatment

Various reports that fewer birds and insects are seen after the sprayers go by

Lab studies have shown high toxicity of both chemicals to wildlife

• Lambda-cyhalothrin

– Lower toxicity for birds

– High toxicity for pollinators

– Moderate to high toxicity for fish & aquatic invertebrates

• Chlorpyrifos

– High toxicity to birds & beneficial insects, including pollinators • LD50 for pheasants = 8.41 mg/kg

– Very highly toxic to freshwater fish & invertebrates

– Moderately toxic to mammals

– Banned for household & pet uses since 1997

What is actual exposure risk in the field?

• Reduced food supply for fast-growing chicks

• Sublethal effects

– Morbidity vs. mortality

• Altered brain activity, altered behaviors, lethargy, reduced weight gains

Drift distances reported in the literature vary widely (5-75 m), which has implications for:

• Effectiveness of buffer practices

• Design of all public & private set-aside acres

Insecticide impacts on wildlife may be:

• Direct

– Primary exposure • Breathing, skin contact, eating

– Secondary exposure • Eating another exposed animal

• Indirect

– Impacts to the animal’s habitat • Reduced food availability

• Reduced habitat cover

http://ncpedia.org/wildlife/northern-bobwhite-quail

Need for balance between:

• Production agriculture for food & fiber

– Supply & demand/need for pesticide-treated products?

• Wildlife

Potential solutions:

• Integrated pest management

• Cover crops

USDA/NRCS – Lynn Betts

Websites for Further Reading & Resources

• U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program: Pesticide National Synthesis Project http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php

• The Xerces Society – Are neonicotinoids killing bees? http://www.xerces.org/neonicotinoids-and-bees/

• American Bird Conservancy (ABC) – Threats to Birds: Pesticides http://abcbirds.org/threat/pesticides/

• Minnesota Department of Agriculture – Chemicals: Pesticides http://www.mda.state.mn.us/chemicals/pesticides.aspx

• Center for Food Safety – Pollinators & Pesticides http://www.centerforfoodsafety.org/issues/304/pollinators-and-pesticides

• University of Minnesota Extension – Agriculture http://www.extension.umn.edu/agriculture/

• Minnesota Department of Natural Resources – General Info: http://www.dnr.state.mn.us

– Minnesota Prairie Conservation Plan: http://www.dnr.state.mn.us/prairieplan/index.html

– Prairie Protection for Landowners: http://www.dnr.state.mn.us/prairierestoration/index.html