Burrowing Rodent Control on Organic farms

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Burrowing Rodent Control on Organic farms

• Thomas Wittman

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Gopher and Mole and Vole
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General Biology of Gophers

• Thomomys bottae is most common in our area
• Named Pocket gopher because of cheek pockets
• Fur is adapted to wet soil
• Front teeth protrude through lip to aid digging
• Mostly use facial whiskers to navigate in dark
• Uses sensitive tail to back up

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Meet a Gopher
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Gopher Distribution
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Gopher Life Cycle and Breeding

• Lives three to five years
• Does not hibernate and can be active any time
• Can have three to five litters per year of two to
  ten young
• Female is pregnant for 18 days, young are weaned
  in 5 to 8 weeks
• Mother drives young off and dispersal begins,
  usually 3 to 400 feet from old burrow
• Nocturnal grazers

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Gopher Lifestyles

• Solitary with own burrow containing nests, food
  caches , dumps for feces and water sump holes to
  avoid flooding
• Territorial by nature and will fight to the death
  if caged together, gophers will share burrows
  during mating season
• Some gopher burrows are common and used by many
  gophers
• Re-occupancy of burrows is rapid within minutes
  or hours

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Gopher in Tunnel
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Gopher Field Facts

• Can dig 3 to 4 feet per hour in hard ground
• A male home range can be up to 300 square yards.
  A females may be half that size
• Range size decreases as population increases
• There can be from 1 to 200 gophers per acre but
  usually range from 24 to 36

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Kinds of Gopher Damage

• Loss of all kinds of woody, bulbous and annual
  plants, especially new rootstock
• Destruction of underground utility cables
• Destruction of irrigation pipes, especially drip
• Loss of effective overhead irrigation due to
  channeling
• Earthen dams can be penetrated
• Loss of rangeland quality due to seedbeds for
  invading annuals

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Burrow System

• Burrow system can be up to 3 hundred square yards
• There are surface mounds and feeding burrows
• Burrows are plugged during inactivity or nesting

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Gopher Mound and Tunnel Facts

• Pocket gophers are number one tunnel maker of
  North American rodents. Some as long as 800 feet
• A gopher builds up to three mounds per day and
  averages 70 per month
• Studies show some sites with 6,000 and up to
  23,000 mounds per acre

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Nesting Site
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Identifying Gopher, Mole and Vole Burrows

• Gopher mounds are fan shaped and have plug
• Mole hills are rounder and do not have a plug
• Voles do not use a deep burrow system for
  feeding, but surface feed instead. Trails can be
  seen in grass on surface
• Gophers and voles eat vegetation
• Moles eat insects and worms and are generally
  believed beneficial
• Mole mounds can be tolerated if cleaned up before
  grass under soil dies

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Gopher Mounds and Mole Hills
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Gopher Mound
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Mole Mound
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Mole Mound
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Mole Mound
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Moles

• Diet consists of insects, grubs, worms, spiders,
  snails, beetles.
• One litter per year.
• Short brown velvety fur.
• Active year round but antisocial.
• Prefers moist, sandy loam soils.
• Paddle like fore feet with prominent nails.
• Lacks external ears and eyes appear to be
  missing.

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Mole Traps
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Meet a Ground Squirrel
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Basic California Ground Squirrel Biology

• Burrows are 4 inches in diameter, 5 to 30 or more
  feet in length and go to a depth of 2 to 4 feet.
• Breed once a year, 7-8 per litter from December
  to April
• Eat grasses and plants in Spring, seeds and nuts
  in fall

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Ground Squirrel Control

• Trapping with live and kill traps
• Conibear No. 110, box traps, Tomahawk, Black Fox
  or Havaheart
• Fumigating with gas cartridges
• Purchase from Ag Commissioner or hardware store
• Best done in winter or spring or after irrigation
• Toxic Baits
• Rodetrol may work if bait stations are on paths
  and it is fall
• Habit Modification
• Eliminate brush piles and debris
• Destroy burrows constantly by disking or other
  means
• Rodent Torch blasting
• Shooting

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Black Fox Repeating Squirrel Trap
13 Squirrels
8 Squirrels
www.thetrapmaker.com 45.00
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Ground Squirrel Containment Barriers

• Can discourage dispersal or invasion because
• Ground squirrels are visually oriented animals
  that have a strong need to keep their burrow
  entrances in sight at all times.
• Vinyl barriers
• Root Guard, lawn edging strips or any wide
  slippery material
• Wood slatted privacy fencing (at least 3 high)
  in conjunction with wire mesh and vinyl barriers
• Tall grasses used along with other barriers can
  lead to permanent solution
• Electric Fence set at 1 and three inches over
  plastic weed barrier

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Common Ground Squirrel Traps
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Home Made Squirrel Trap
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Voles

• Voles are small and weigh about 1 to 2 ounces.
• Important food source for predators such as (i.E.
  Snakes hawks).
• Life expectancy is short, can have up to 15
  litters per year.
• Many vole populations are cyclic.
• 2 to 10 cm. Tail, grayish brown above, paler
  below, long and shaggy fur.
• Blunt snouts, short ears, plant eaters.

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Vole Runs
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Vole Runs and Damage Control
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Excluding Gophers and Moles

• Wire baskets made of aviary wire around roots of
  plants and trees
• Wire to a depth of two feet below and six inches
  above a garden bed
• Use above ground barriers to slow invasion
• Trenches can be used as barriers if they are deep
  enough (at least two feet)

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Overall Farm Gopher Strategy

• Reduce Population by trapping efficiently
• Trap all year round to reduce spring mating
  population
• Make trap site visits as quick as possible
• Recognize potential nesting sites and focus on
  them
• Install barriers to limit invasion
• Trap in adjacent areas and work with neighbors
• Scout for new mounds all around farm not just in
  fields

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Field Scale Control Measures

• Plant Buffer Strips and use rotations
• Small grains can be effective
• Clovers will attract gophers
• Flood irrigation
• causes the soil to stick to their claws and fur.
  It also draws heat out of their bodies. Wet soil
  limits the exchange of oxygen and other gases
  between burrows and soil and discourages pocket
  gophers.
• In windbreaks and orchards, remove weeds that
  have large roots that are attractive to gophers.
  Also, plant less susceptible varieties of trees
  and shrubs.

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Sour Clover (Melilotus indica)

• contains Coumarin in its roots.
• Sour clover is nitrogen fixing
• re-seeds readily
• Attracts Beneficial Insects
• May be excellent for orchard covers

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Root Barrier can be effective gopher, mole, vole
and squirrel fence
Cost 1.50-4.00 per foot Depending on thickness
Leave 6 to 8 inches above grade
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Barrier for gophers, moles, squirrels and rabbits
Wire is buried 16-24
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Can Gophers Climb?
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Predators of the Pocket Gopher, Moles and Voles
Our cat is a petite tabby, weighing only 9.5
pounds

• Our cat's records for the past several years are
• 2001 58 gophers, 4 mice
• 2002 65 gophers, 7 mice
• 2003 43 gophers, 6 mice, 2 moles
• 2004 28 gophers, 4 mice

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Gopher Snake
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Barn Owl Nest Box

• Barn owls range up to two miles from nestbox
• A family is usually two adults and two chicks
• One barn owl family can eat up to one thousand
  gophers per season

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Barn Owl Pellets
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OMRI Generic Material products that are
restricted for organic production.

• Quintox Rat amp Mouse Bait- PELLETS (company
  Bell Laboratories, Inc. ph
• 608-241-0202 contact Joni Abrams, web
  www.belllabs.com)
• OMRI Generic List
• Vitamin D-3 Synthetic and allowed as rodenticide
  under 205.601(g)(2)
• Sulfur Dioxide Synthetic and allowed as a
  rodenticide under 205.601(g)(1)
• underground rodent control only (smoke bombs)

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Quintox Poison Bait Use

• Cholecalciferol (vitamin D3), trade name Quintox,
  causes calcium to collect in the bloodstream
  resulting in the failure of clogged organs.
• Rodents can consume a lethal dose in a single
  day's feeding( 1/10 oz. -2.8 grams of Quintox can
  kill a mouse, while 1/4 oz.-7 grams is a lethal
  dose for a rat,) or they can accumulate smaller
  feedings through a couple of days.
• Once a rodent eats Quintox, all feeding stops,
  unlike anticoagulants where feeding continues.
• The toxicant mobilizes calcium from the rodent's
  bones , producing hypercalcemia and heart
  failure.
• It acts faster than anticoagulants.
• On OMRI List but restricted

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Corn Cobs can lead to dehydration due to excess
cellulose intake
Target animal must ingest for six days to work
Active Ingredients Corn Oil Concentrate . . . .
. . . . . . . . . . 0.005 Inert
Ingredients Wheat Flour . . . . . . . . . . . .
. . . . . . . . . 1.000 Molasses . . . . . . .
. . . . . . . . . . . . . . . . 5.000 Corn . .
. . . . . . . . . . . . . . . . . . . . . 93.995
Total . . . . . . . . . . . . . . . . . . . .
. . . 100.000
www.rodtrol.com
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Burrow Builders for Poison
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Probe Style Applicators
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Phostoxin or Phosphine Gas
Generic Name Aluminum Phosphide Trade Names
Phostoxin, Phosphume, Phostek, etc. EPA
Shaughnessy Code 066501 Chemical Abstracts
Service (CAS) Number 20859-73-8 Year of Initial
Registration 1978 Pesticide Type Solid Chemical
Family Inorganic Phosphides U.S. and Foreign
Producers Degesch America, Inc. Research
Products Co., Pestcon Systems, Inc., Bernardo
Chemicals. 2. Use Patterns and Formulations
Application Sites Indoor fumigation of
agricultural food commodities, animal feeds,
processed food commodities and non-food
commodities (tobacco). Outdoor fumigation for
burrowing rodent and mole control. Application
Rates 30 tablets or 75 pellets per square foot
for fumigation of mills and warehouses 1-4
tablets or 5-20 pellets for rodent burrows.
Formulations Tablets and pellets powders in
bags, envelopes and other types of containers.
3. Science Findings Summary Science Statement
The Agency has determined that the registered
uses of this chemical will not generally cause
unreasonable adverse effects to humans or the
environment if used in accordance with the
approved use directions and revised precautionary
statements prescribed by the registration
standard.
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Repellent Liquids

• Drenches of foul tasting and smelling liquids can
  be effective for single plants and trees (Ropel,
  castor oil)
• Coyote and cat urine can also work in specific
  areas for a short time
• Fish emulsion and other meat products can work
  around perennials

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Castor Oil
Fox Urine
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Sonic and Other Noisemakers

• May be effective in small area for short time
• Can be homemade or purchased at craft fairs
• No scientific research yet exists

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Flooding, Gassing and Blasting

• Flooding can be effective but often gopher gets
  away
• Gassing using lawn mower, tractor and auto
  exhaust might be effective
• Sulfur bombs have been known to work in some
  cases
• Rodent Torch and Blaster popular in orchards but
  are loud, expensive and dangerous but can be very
  effective due to burrow destruction

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Flooding Caddy Shack Style
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Krush Gopher Gasser
Standard Ag Dept calcium nitrate gas cartridges
Insert into fresh burrow
THE CARBON MONOXIDE PISTOL SET
Available from Safekrush.com 415.00
Force gas in with blower
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Rodex Gopher Torch
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Carbon Monoxide Generator

• 1 Open the den.2 Place the exhaust (orange
  fitting) over the hole.3 Start the carbon
  monoxide generator. That is it!!    Carbon
  Monoxide GeneratorIntroductory special 350.00
  (regular price 450.00)
• Veterinarians confirm that carbon monoxide is
  painless. Like the tragedy of people sleeping in
  a closed camper with a charcoal fire for warmth.

Why not just use your tractor, truck or mower?
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Gopher Traps History

• First patented and commercially produced trap was
  the Woods Gopher trap, Patented in 1870 by
  Romanso Wood of Santa Cruz, California
• By 1900 12 more traps were patented all from
  California and Zephyr Macabee developed and
  patented his trap that has survived unchanged to
  this day

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Basic Trapping Strategies

• Focus on one area at a time
• Too many spread out traps leads to confusion and
  lost traps
• Observe natural barriers and work to or from them
• Minimize time spent at each site
• Trap at freshest sites
• Eliminate all gophers or moles in each trapping
  area before going on to next
• Gophers seem to repopulate very quickly
• Prioritize starting point to protect most
  valuable or cherished plants
• Flag and stake traps for easy locating

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Locating Run Entrance
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Find freshest run
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Trapping Techniques General Rules

• Set traps in early morning or late afternoon
• Be sure to trap all year as in winter breeding
  population is lowest
• Check traps often
• Wear gloves
• Add food around traps
• Be careful not to collapse mounds when walking
• Stake traps to find them and keep them in place

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Macabee and Box Style Traps

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Local Gopher Trap Collection
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Live Catch Gopher and Mole Traps
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Trapping Techniques Macabee and Box Types

• If using Macabee or box type traps, excavate at
  mound or probe for burrow, trap both ends of
  exposed burrow
• Check daily by pulling traps out of burrows
• Can be made more effective by extending burrows
  after traps with tubes

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Trapping Techniques Cinch

• Advantages of a Cinch trap
• Trap from surface very little digging
• Checking traps is easy
• Removing gopher is easy
• Easy to spot in field

Cinch Trap Company Don Sprague Sales 1-800-841-567
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Cinch Trapping Strategy

• Trap on surface mounds and openings
• Watch for fresh digging
• Open mound carefully and pull out loose soil
• Insert trap being careful not to push in more
  loose soil
• Be sure to leave burrow open

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Cinch Trapping Technique
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Proper Cinch Setting Technique
Right
Wrong
Tunnel Exit
Feeding hole
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Resources and Questions

• A lot of information is on the web. Use keywords
  like gopher trapping, pocket gopher, gopher
  traps
• Talk to neighbors about joining you in this
  mission
• Enlist the aid of trappers or professional
  landscapers

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• Web Resources for Gopher, Mole and Vole
  Control
• www.bugspray.com A very complete online
  catalog and information
• site with an index of pest problems and a
  narrative solution portion
• linked to products
• http//www.nwtrappers.com/catalog/traps/gophermole
  .asp Also known as
• Cumberlands Northwest Trappers Supply is
  probably the most complete
• trap supply house in the US. Cinch, No-mole,
  Macabee, drenches and many
• other products at reasonable prices.
• www.molepro.com This site is mainly concerned
  with moles and is packed
• with useful information about myths and natural
  history of moles. There
• are many tips on keeping them away and on
  trapping
• Common Sense Pest Control by Bill and Helga
  Olkowski and Shiela Daar
• This book is available from almost any book
  seller and is an
• encyclopedia of useful non toxic information
  about pest control and has
• a great section on gophers and other burrowing
  animal pests.

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