Pocket Gopher Control Options

Transcription

Pocket Gopher Control Options
Charlie Lee
Extension Specialist, Wildlife
Department of Animal Sciences and Industry
Kansas State University
clee@ksu.edu
Not really gophers
Range
g in Colorado
Gopher Biology
Plains
pocket gopher (Geomys
bursarius)
10” - 12” in length with tail
fur
fur-lined
lined external cheek pouch
lips close behind incisors
two longitudinal grooves on incisors
Gopher Biology
Botta
pocket gopher (Thomomys
bottae)
5” - 10” in length with tail
Color varies from almost white to black
Small fore feet and claws
Single longitudinal groove
on incisors
Pl i P
Plains
Pocket
k tG
Gopher
h
Reproduction (Plains)
February
F b
to
t April
A il
Gestation about 1 month
1-6 young born hairless, eyes
and
d ears closed
l
d
Weaned in 6 weeks
Sexual maturity at 1 year
Reproduction (Botta)
Year aro
around
nd reprod
reproduction
ction
Usually during normal wet seasons
3.7
3 7 litters/yr in irrigated fields
fields, 1
1.7
7 litters/yr
in non-irrigated alfalfa
Gestation
about 1 month
1-6 young born hairless, eyes and ears
closed
Weaned in 6 weeks
Sexual maturity at 9 months
6-8g
gophers/acre
p
(Plains)
(
)
16-20 gophers/acre (Botta)
may live
li 7 years, average iis 2
2-3
3 years
Home range up to 700 yd2
Factors affecting
distribution
Plant
food
Soil composition
< 30% clay
> 40% sand
Silt content not a factor
No more than 10% rocks
Burrow around rocks >1”
Soil
in top 8”
depth important to ameliorate
temperatures. Need at least 4” of soil.
Burrow System Extensive
2
depth levels, tunnel system ~ 500 ft.
As many as 300 surface mounds/animal/year
Few mounds are built when g
ground is frozen
Vigorously defend the tunnel system
Soil mixing
1
gopher = 2.25 tons of soil to
surface/yr
52 cubic feet of soil
7
gophers
g
p
would cover the surface of 1
acre 1 inch deep in 10 years or 6 inches
p in 60 yyears
deep
Mounds may cover 88-15% of area
Can Reduce Forage
Alfalfa
yield is 30% - 40% less in the areas
they inhabit
Alfalfa density is 28% - 32% less
On sands and silty range sites in NE, reduced
forage 18-49%
Increase weedy species
Plant
Pl t biomass
bi
(roots,
( t stems
t
and
d both)
b th) was
reduced by 1/3 directly over active tunnels in
Kansas
In alfalfa fields, stems and leaves constitute
23% of the diet and alfalfa roots are 71%
Gopher influence on alfalfa in
Nebraska
400
350
300
250
200
Gophers
No gophers
150
100
50
0
Alfalfa Alfalfa yield
Other
plants/m2
g/m2
species/m2
Other
species
yield/m2
i ld/ 2
Luce 1981
Food Habits
(strict herbivores)
Feed on plants in 3 ways:
Feed
on roots when digging
Stored carbohydrates
Feed
aboveground near burrow opening
Rhizomes
Pull
P ll
vegetation
t ti iinto
t ttunnell ffrom below
b l
prefer alfalfa and dandelions
University of Nebraska
Study
Wrangler
- tap rooted variety
Spredor 2- fibrous rooted variety
y
Wrangler
out-yielded Spredor 2 by 9%
9%,
but Wrangler yields were reduced by
19% when pocket gophers were
present.
Things that don
don’tt work
Juicy
Fruit Gum
12 day test with 6 gophers
Individually
I di id ll weighed
i h d and
d caged
d
Each supplied with 1 stick unwrapped and rolled
gu a
gum
along
o g with rodent
ode cchow
o a
and
d app
apple
e
4 of the 6 gophers consumed the gum. One ate
11 sticks of gum
No deaths, illnesses, behavior changes or weight
loss occurred
Things that don
don’tt work well
Exploding
burrows
Control Methods
Cultural
crop varieties
Crop rotation
Grain buffer strips
p
Flood irrigation
Control Methods
Trapping
Macabee
Victor
Death-Klutch
California box type
Albano
Trapping as a control
45%
40%
35%
30%
25%
Macabee
Cinch
Blackhole
20%
1 %
15%
10%
5%
0%
Capture efficiency
60 traps, 5 days= 256 gophers
Control Methods
66 products
d t registered
i t d iin C
Colorado
l d
Toxicants
Strychnine (0.25-0.5%)
Zinc phosphide (2%)
Chlorophacinone (0.005%)
Diphacinone (0
(0.005%)
005%)
Fumigants
Effectiveness (%) of three
t i
toxicants
t for
f pocket
k t gophers
h
50
45
40
35
30
25
20
15
10
5
0
.40% strychnine oats
.37% strychnine
y
grains
2% Zinc phosphide
June
July
August
Sept
Alpha Wildlife Research 1998
Martin’s Gopher
p
Bait 50R
Subsoil application no more than 11-2 pounds of bait per acre
using 20 to 30 foot row spacings not more often than
once every 30 days
Strychnine Alkaloid ………………………….0.50%
Inert Ingredients………………………………….99.50%
Prozap
p Agri-brand
g
Oat Groat
Zinc Phosphide Oat Bait
For spot treatment in and around buildings,
orchards and groves, vineyards, sugarcane fields,
rangeland and noncrop areas
areas.
ACTIVE INGREDIENT:
Zinc Phosphide . . . . . . . . . . . . . . . . . . . . . . . 2.0%
INERT INGREDIENTS: . . . . . . . . . . . . . . . . . . . . 98.0%
Total 100.0%
100 0%
Efficacy was 89.7% with 1 baiting at 7.75lbs/acre
National Wildlife Research Center
Research Update
Within
5 days after baiting, pocket
gophers consumed or transported bait
@ 95% of sites.
88%
of the pocket gophers trapped had
ingested the oat groat biomarker bait.
National Wildlife Research Center
“High
High bait acceptance may
have been due to preference
f the
for
th oatt groatt in
i the
th absence
b
of g
green alfalfa. Previous
studies indicated low bait
acceptance of all baits when
green alfalfa was present.”
Long lasting baits
Gophers
are quick to invade
unoccupied burrows systems
Invading gophers will use existing food
stores (baits) left by previous resident
Parafinized baits readily accepted
Baits may
y be consumed on location or
moved to nests
Make sure y
you use enough
g bait ((> 100 g)
Best Times to Treat
Just
J t
after
ft ground
d thaws
th
before
b f
young
y
g are born.
Early spring when young are in
tunnel.
tunnel
In late summer to fall when
juveniles are dispersing.
Burrow Builder
Crisscross
pattern in areas where
mounds are dense.
Do not travel over 25’ outside of the last
mound.
Apply 1-2 pounds bait/acre.
Drag treated areas to level all mounds
mounds.
Check in 10 days.
Acres Covered
Tractor Speed (mph)
Acres/Hr
2.0
2
0
3.0
40
4.0
5.0
4.8
4
8
7.3
98
9.8
12.5
20 foot spacing
p
g
Soil Moisture Critical for
Building Artificial
f
Burrows
Too
wet to plow
Handful
In
sticks together when squeezed
sand 1-2 days after rain or irrigation
Is it faster than trapping?
25
foot spacing
4 mph
Treat about 60 acres day
Passes of Burrow Builder
Across Rows off Mounds
Pounds of Bait Delivered/Acre
with Different Distances Between
Passes
Lbs./1000 ft.
Applied
10
0.5
10
1.0
1.5
20
2.0
2.5
30
3.0
2.2
44
4.4
6.5
87
8.7
10.9
13 1
13.1
14
1.6
31
3.1
4.7
62
6.2
7.8
93
9.3
20
1.1
22
2.2
3.3
44
4.4
5.4
65
6.5
24
.9
18
1.8
2.7
36
3.6
4.5
54
5.4
30
.07
1
1.5
2.2
29
2.9
3.6
44
4.4
Burrow Builder Companies

Rue R. Elston Co., Inc.

Sioux Falls
Falls, SD
800-845-1385
Benson, WI
Benson
320-843-4932

Western Alfalfa
P.O. Box 186
Herndon KS
Herndon,
785-322-5515
Red Ball
♦
$800 - $3,000
Eckroat Seed Co
Co.
Oklahoma City, OK
800-331-7333
All American Ag
16441 Hwy 12
Touchet, WA 99360
(509) 520-4055
http://www.coopext.colostate.edu/wildlife/vendors_of_supplies.html#Bait
Border Control Strategy
Treat
early in spring to remove reproducing
females
Keep a 40 meter border gophergopher-free
Either trapping or handhand-treating burrows
Canada study
y showed 213 mounds/2.5 acres
in control and 19 mounds/2.5 acres with
perimeter trapping
Perimeter
P i t trapping
t
i intercepted
i t
t d 81%
Use
2,4-D to reduce forbs in grass borders
2,4-
Fumigants?
Fumigant Dispersal
Trial
1
1-- artificial burrow system
100 yards of 2” clear pvc with 2 levels
sensors for
f CO att 12’ and
d 20’
1 or 2 gas cartridges with or without blower
Best
concentrations of CO were obtained with
2 cartridges and low speed blower
Without blowerblower- minimal dispersal of gas
Nolte, 2000
Fumigant Dispersal
Trial
2-- field test: 1or 2 cartridges with or
2
without blower
Efficacy was 1313- 16% after 48 hours
Gopher tunnels are porous, and
gophers plug tunnels when they detect
airflow
Effective Control
Trapping
pp g
- low numbers,, follow-up
p
to hand-baiting.
Hand baiting
g - low to moderate
numbers, follow-up to burrow
builder.
Burrow builder - high numbers or
large acreage.
Maintain populations at low levels
after initial control!!