Biology and Management of Amur honeysuckle (Lonicera maackii) R.J. Smeda, S.A. Riley

Biology and Management of Amur honeysuckle (Lonicera maackii) R.J. Smeda, S.A. Riley

INTRODUCTION 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)

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

Plants in MO initiate growth in April and retain leaves into December 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

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 eradicate infestations

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 jimmccormac.blogspot.com M.S. research of S.A. Riley 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) Basal 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 1 st Cut Distal 2 nd Cut

Staining pattern Nonviable 40X Viable

Results: Harvest Timing Viability (%) Early-September Mid-September Late-September Mid-October Late-October Early-November 0 d a 22 c 61 b 83 ab 86 a 90 a a Means within each column followed by the same letter are not significantly different using Fisher s Protected LSD at P=0.05 No seed viability detected until mid-september Maximum viability reached in early-november

Methodology for seed production: 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) 50 random berries harvested and seeds extracted and counted

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) a Number in parentheses indicates the standard error of the mean. b Means within each column followed by the same letter or without letters not significantly different using Fisher s Protected LSD at P=0.05.

Methodology for berry predation 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

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 regrow to 1 meter before treating Applications were made on June 27 and July 8, 2011 and July 9 and 18, 2012

Treatments Chemical 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 + Metsulfuron Aminocyclopyrachlor + Metsulfuron + Imazapyr *g ai/ha 131.5 + 41.9* 0.5% V/V MSO 271.4 + 87 + 376.8* 0.5% V/V MSO

Experimental design was a randomized complete block with 5 replications at each location Applications made with a CO 2 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)

Visual Control Examples 0% 50% 100%

Results Foliar applications 28 DAT; % Visual control 2011 2012 100 100 80 80 60 60 40 40 20 20 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Aminopchlor + Metsulfuron + Imazapyr Moberly LSD=17 Columbia LSD=17 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Moberly LSD=17 Ashland LSD=13 Aminopchlor + Metsulfuron + Imazapyr

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 2012 100 100 80 80 60 60 40 40 20 20 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Aminopchlor + Metsulfuron + Imazapyr Moberly LSD=20 Columbia LSD=17 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Moberly LSD=21 Ashland LSD=17 Aminopchlor + Metsulfuron + Imazapyr

120 DAT; % Visual control 2011 2012 100 100 80 80 60 60 40 40 20 20 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Aminopchlor + Metsulfuron + Imazapyr Moberly LSD=18 Columbia LSD=14 0 Glyphosate 2,4-D Triclopyr + Imazapyr 2,4-D + Dicamba + Fluroxypyr Picloram + FLuroxypyr Triclopyr + Fluroxypyr Sufometuron + Metsulfuron Aminopchlor + Metsulfuron Moberly LSD=18 Ashland LSD=13 Aminopchlor + Metsulfuron + Imazapyr

120 DAT Untreated Glyphosate

120 DAT 2,4-D Aminocyclopyrachlor + 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?