Biology and Management of Amur honeysuckle (Lonicera maackii)

R.J. Smeda,

S.A. Riley

• Lonicera spp. are known as honeysuckles and are comprised of vining perennials and shrubs

• Grape honeysuckle (Lonicera reticulata) is an example of a native vining honeysuckle

• This vine can grow up to 4.5 meters and prefers to grow up existing vegetation

MDC (2013)

INTRODUCTION

• Invasive bush honeysuckles are a group composed of 4 species– Amur

– Morrow’s

– Tartarian

– Belle’s(Vermont 1998)

• Stems of invasive shrubs are hollow which is distinguishable from native solid-stemmed honeysuckles

• Amur honeysuckle was introduced to the

U.S. in the late 1800s(Dirr 1983)

• Its invasion has been widespread

because seeds are vectored by birds

(Luken 1988)

www.invasive.org

• Amur honeysuckle is

common throughout

Missouri

• Prefers partially shaded

habitats:

– treelines,

– fencerows

– other undisturbed areas

• Reproduction is by seed only

• Berries contain from 3 to 8 seeds

• Shrubs produce thousands of berries each season

• Berries are eaten by birds and seeds dispersed

www.hiltonpond.org

www.ohionatureblog.com

• Shrubs form a

dense thicket that

may displace

desirable understory

species due to light

inhibition and

allelopathic effects

• Amur honeysuckle

can reach 6 m in

height

• Plants in MO initiate

growth in April and

retain leaves into

December

Infestated areas are quite visible following first snow events

December 8

Amur honeysuckle is an urban and rural problem Columbia Missourian

September 16, 2011

The St. Louis Audubon Society currently supports efforts to eradicateinfestations

Outline

• Study 1: Seed Biology

– Seed viability through time

– Berry counts

– Bird predation through time

• Study 2: Herbicide Trial

– Herbicides for brush control

– Response of Amur honeysuckle to herbicides

M.S. research of S.A. Riley

jimmccormac.blogspot.com

forestrenewal.blogspot.com

Objective: Seed Biology• Assess timing for maturity of Amur honeysuckle

seeds

• Estimate seed production capacity

• Determine reduction in berry population on shrubs as seeds reached maturity

Tetrazolium Assay

• Exposure of seeds to a tetrazolium solution is an accepted way to assess viability

• Actively respiring tissues are stained red by the TZ solution

• Non-respiring tissues are not stained

• For Amur honeysuckle all internal tissues of seeds must be stained for positive viability assessment

Methodology - tetrazolium

• Berries (20) dissected for seed harvest at different times for 2 MO locations (2011 and 2012)

• Seeds immersed in water overnight to facilitate dissection

• Seeds were dissected and distal end was place in 1% TZ solution overnight at 35 C in a temperature controlled chamber

• Seeds were dissected and viability assessed Distal

Basal

1st Cut

2nd Cut

Staining pattern

Nonviable

Viable

40X

Harvest Timing Viability (%)

Early-September 0 da

Mid-September 22 c

Late-September 61 b

Mid-October 83 ab

Late-October 86 a

Early-November 90 a

a Means within each column followed by the same letter are not significantly different using Fisher’sProtected LSD at P=0.05

• No seed viability detected until mid-September• Maximum viability reached in early-November

Results:

Methodology for seed production:

• 50 random berries harvested and seeds extracted and counted

• Over 4 site years, bird netting placed over shrubs and weed block placed beneath shrubs

• All berries counted in October on 5 random shrubs per site year (4)

Amur honeysuckle seed production per shrub in Missouri

Location Total berry # Seeds per berry

Total seed production

Ashland, 2011 1,554 (+ 366)ab 2.8 (+ 0.1) a 4,477 (+ 1174)

Columbia, 2011 2,067 (+ 633) 3.3 (+ 0.1) a 7,161 (+ 2378)

Ashland, 2012 3,172 (+ 637) 1.0 (+ 0.2) b 3,150 (+ 1034)

Columbia, 2012 4,173 (+ 1927) 0.7 (+ 0.1) b 2,844 (+ 1031)

aNumber in parentheses indicates the standard error of the mean.bMeans within each column followed by the same letter or without letters not significantly different using Fisher’s Protected LSD at P=0.05.

• Netting and weed mat was placed beneath shrubs to prevent predation of fallen fruits

• Initial berry counts were taken in late September each year until all berries disappeared

• Additional counts of 4 shrubs at 2 locations were taken every 15 days

• Experiment was a randomized complete block with 4 replications; data generated for 4 site years

Methodology for berry predation

Means not followed by the same letter for each curve not significantly different using Fisher’s Protected LSD at P=0.05.

• 83% viability was observed by mid-October

• 250 berries per week were lost due to predation from October through December

• Large numbers of viable seed are dispersed through the winter months

Objective: Herbicide Study

• Determine herbicide efficacy on Amur

honeysuckle using foliar (summer)

applications

newyorkinvasivespecies.info

Materials and Methods

Foliar Applications

• Two locations: Columbia and Moberly, MO in 2011; Ashland and Columbia, MO in 2012

• Amur honeysuckle was mowed in fall of 2010 and 2011 with shrubs allowed to re-grow to 1 meter before treating

• Applications were made on June 27 and July 8, 2011 and July 9 and 18, 2012

TreatmentsChemical Rate (g ae/ha) Surfactant

Glyphosate 1577 3.36 kg/ha AMS

2,4-D 1317.6 0.25% V/V NIS

2,4-D + Dicamba + Fluroxypyr 785 + 98.1 + 98.1 -

Triclopyr + Imazapyr 3 %v/v + 0.125%v/v 1% V/V MSO

Picloram + Fluroxypyr 375.3 + 302.8 0.5% V/V NIS

Sulfometuron + Metsulfuron 69 + 18.4* 0.25% V/V NIS

Triclopyr + Fluroxypyr 578.2 + 192.7 1% V/V NIS

Aminocyclopyrachlor +

Metsulfuron131.5 + 41.9* 0.5% V/V MSO

Aminocyclopyrachlor +

Metsulfuron + Imazapyr271.4 + 87 + 376.8* 0.5% V/V MSO

*g ai/ha

• Applications made with

a CO2 pressurized

backpack sprayer at 374

L ha-1 using TeeJet XR

8002 nozzle tips

• Plots were 2 by 7.6 m

• Visual ratings of

honeysuckle injury (0 =

no control, 100 = plant

death) at 28, 90, and

120 days after treatment

(DAT)

• Experimental design

was a randomized

complete block with 5

replications at each

location

Visual Control Examples

100%50%0%

Results Foliar applications

28 DAT; % Visual control

2011

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=17

Columbia LSD=17

2012

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=17

Ashland LSD=13

• Acceptable control by industry standards is 90% or greater

• Several herbicides exhibited >80% control by 28 DAT:

– aminocyclopyrachlor + metsulfuron + imazapyr

– aminocyclopyrachlor + metsulfuron

– glyphosate

90 DAT; % Visual control

2011

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=20

Columbia LSD=17

2012

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=21

Ashland LSD=17

120 DAT; % Visual control

2011

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=18

Columbia LSD=14

2012

Glyphosa

te2,4

-D

2,4-D

+ D

icam

ba + F

luroxy

pyr

Triclopyr

+ Im

azapyr

Piclora

m +

FLuro

xypyr

Sufom

eturo

n + M

etsulfu

ron

Triclopyr

+ F

luroxy

pyr

Aminopch

lor + M

etsulfu

ron

Aminopch

lor + M

etsulfu

ron +

Imaza

pyr0

20

40

60

80

100

Moberly LSD=18

Ashland LSD=13

120 DAT

Untreated Glyphosate

120 DAT

2,4-DAminocyclopyrachlor + Metsulfuron

+ Imazapyr

• Control of Amur honeysuckle had greatly improved by 90 and 120 DAT from 28 DAT.

• Best treatments across site years were:

– aminocyclopyrachlor + metsulfuron + imazapyr

– aminocyclopyrachlor + metsulfuron

– glyphosate

Conclusions

• Amur honeysuckle seeds are viable by mid-October

• Large numbers of viable seeds are dispersed every winter through bird predation

• Control of this shrub can be achieved with a summer application of an aminocyclopyrachlor containing herbicide or glyphosate.

• We can only stop the spread of infestations by preventing berry production

Questions?