CtlControl off bbdbarbed goatgrassggt (AilAegilopsgpti i ... · Mti tdb th d f fll /lt titt tt fi...
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C t l fb bd t (A il ti i li )i ti l d Control of barbed goatgrass (Aegilops triuncialis) in serpentine grasslands Control of barbed goatgrass (Aegilops triuncialis) in serpentine grasslands Paul A Aigner and Rhett J Woerly University of California Davis Donald and Sylvia McLaughlin Reserve Lower Lake CA Paul A. Aigner and Rhett J. Woerly , University of California Davis, Donald and Sylvia McLaughlin Reserve, Lower Lake, CA ff i f b Serpentine grasslands are known for being relatively free of the invasive species that typify other Effects on native forbs California grasslands. Recently the special status of serpentine grasslands as strongholds of native plant diversity has been threatened by the spread of barbed goatgrass (Aegilops triuncialis), a Eurasian annual Native forbs were especially diverse in the study area, with 51 species recorded across all plots, and a that is unique in its tolerance of serpentine soils (Plate 1). Carefully timed prescribed fire, especially Native forbs were especially diverse in the study area, with 51 species recorded across all plots, and a median of 13 species per plot As a group native forbs increased in frequency dramatically on hand‐ that is unique in its tolerance of serpentine soils (Plate 1). Carefully timed prescribed fire, especially applied over two consecutive years has been shown to reduce goatgrass while benefitting many native median of 13 species per plot. As a group, native forbs increased in frequency dramatically on hand‐ pulled early season Fusilade and early season Envoy plots (Fig 3A) All other treatments showed a applied over two consecutive years, has been shown to reduce goatgrass while benefitting many native species (DiTomaso et al 2001 ) At the McLaughlin Reserve in the inner North Coast Range of California pulled, early‐season Fusilade, and early‐season Envoy plots (Fig. 3A). All other treatments showed a trend toward increasing native forb frequency but none differed statistically from controls Of the species (DiTomaso et al. 2001 ). At the McLaughlin Reserve in the inner North Coast Range of California, we found prescribed fire cannot be applied for two consecutive years because the low productivity of trend toward increasing native forb frequency, but none differed statistically from controls. Of the i ht f b i ith ll lt f 1% t h di ith l we found prescribed fire cannot be applied for two consecutive years, because the low productivity of ti l d t d t f l b ild i th d S ti l d eight forb species with an average cover across all plots of >1%, two showed increases with early‐ serpentine grasslands prevents adequate fuel build up in the second year. Some serpentine grasslands d i h fi ill ll season application of grass specific herbicides (Fig. 3B&C). Navarretia jepsonii, a serpentine endemic are so unproductive that fire will not carry at all. annual, had higher cover on early‐season Fusilade plots compared to controls, mowing, and all of the M ti t db th df f ll / lt ti t t tt fi l td i t t tf late‐season herbicide plots (Fusilade, Envoy, and Roundup). N. jepsonnii may have been negatively Motivated by the need for a follow up/alternative treatment to fire, we evaluated nine treatments for affected by Roundup, as it was still actively growing at the time of application. Holocarpha virgata,a their effectiveness controlling barbed goatgrass and for restoring native species cover and diversity: summer annual, had higher cover on early‐season Fusilade and Envoy plots relative to controls. two grass‐specific herbicides —fluazifop [Fusilade II ] and clethodim [Envoy +]—applied before summer annual, had higher cover on early season Fusilade and Envoy plots relative to controls. goatgrass flowering (early‐season), at flower initiation (mid‐season), and at early seed development 8 0.5 6 (late‐season), a broad‐spectrum herbicide (glyphosate) applied late‐season, mowing , and hand pulling. ver a 2009 Plate 3 Control plot summer 2009 Plate 4 Early‐season herbicide application March er A B C cov 0.4 cy 2009 2010 Plate 3. Control plot , summer 2009. Plate 4. Early‐season herbicide application, March 2009 cov a A B C hd 6 ent a 03 enc 2010 2009. ent c Methods Eff t erce ab 0.3 0.3 eque 4 erce Effects on a pe ab b fre ii pe ab In fall of 2007 we established a grid of 100, 2m x 2m plots with 2‐m wide buffers between plots in a goatgrass 4 rgata 0.2 cy 0.2 forb son serpentine grassland with high cover of barbed goatgrass but few other non‐native species (Plates 2, 3). goatgrass a vir ab 0.2 nc 2009 e in f jeps abc serpentine grassland with high cover of barbed goatgrass but few other non native species (Plates 2, 3). We counted goatgrass tillers within a 0 25‐m 2 frame in the center of each plot and stratified the pha ab ab 01 en 2009 2010 0.1 nge 2 etia j abc We counted goatgrass tillers within a 0.25 m frame in the center of each plot, and stratified the experiment into 10 blocks based on tiller density The nine treatments and a non‐treatment control After two years of treatment , 2 ocar 0.1 que 2010 chan arre abc abc experiment into 10 blocks based on tiller density. The nine treatments and a non‐treatment control were assigned randomly within each block Treatments were applied in spring 2008 and 2009 In early all treatments except for Holo ab ab ab ab b eq 0.0 c Nava bc bc bc bc were assigned randomly within each block. Treatments were applied in spring 2008 and 2009. In early M h 2008 2009 d 2010 ( i t th li ti ft t ti 2008 d 2009) d th Roundup and early‐season 0 H b 0.0 fre 01 0 N bc bc c March 2008, 2009, and 2010 (prior to the application of treatments in 2008 and 2009) we measured the f fb bd i f b i b h (l l i l ll lh Envoy resulted in reduced EnvE FusE Hand EnvM EnvL FusM FusL Round Mow ontrol 0 s f Hand FusE EnvE usM EnvL nvM Mow ound FusL ntrol -0.1 FusE FusM Hand EnvM EnvE FusL EnvL ontrol Mow Round 0 frequency of barbed goatgrass, native forbs, native bunchgrasses (almost exclusively Nassella pulchra Envoy resulted in reduced goatgrass frequency relative to En Fu Ha En E Fu F Rou M Con treatment 01 ass Ha Fu En Fus En Env Mo Rou Fu Cont t t t Fu Fu Ha En En F E Con M Rou treatment and Poa secunda), and other annual grasses (Bromus hordeaceus and Vulpia microstachys) in 25, 27‐mm goatgrass frequency relative to controls (Fig 1) Mid season treatment -0.1 ra treatment treatment Figure 3 (A) Change in native forb frequency after one and two years of treatment Error bars represent SEM diameter circular subplots within each plot. In early May 2010, we made visual estimates of cover of all controls (Fig. 1). Mid‐season Fusilade hand pulling and tg Figure 3. (A) Change in native forb frequency after one and two years of treatment. Error bars represent SEM. Solid lines below the bars group treatments that are not significantly different in 2010 by Tukey’s HSD test at species within a 1‐m 2 frame at the center of each plot. Fusilade, hand pulling, and l F il d h d -0.2 oa Solid lines below the bars group treatments that are not significantly different in 2010 by Tukey s HSD test at α=0 05 (B & C) Percent cover of two native forbs after two years of treatment Error bars represents SEM early‐season Fusilade showed go α=0.05. (B & C) Percent cover of two native forbs after two years of treatment. Error bars represents SEM. Letters above the bars group treatments that are not significantly different by Tukey’s HSD test at α=0 05 the best performance, reducing 03 n g Letters above the bars group treatments that are not significantly different by Tukey s HSD test at α=0.05. Abbreviations: EnvE Envoy early season; EnvM Envoy mid season; EnvL Envoy late season; FusE Fusilade early goatgrass frequency by 66%, -0.3 in Abbreviations: EnvE, Envoy early season; EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusilade early season; FusM Fusilade mid season; FusL Fusilade late season; Hand hand pull; Round Roundup 62% , and 52% respectively ge Barbed goatgrass season; FusM, Fusilade mid season; FusL, Fusilade late season; Hand, hand pull; Round, Roundup. from the pre‐treatment -0.4 ng Effects on other non natives frequency of about 0.7. Early‐ an Effects on other non‐natives frequency of about 0.7. Early season Envoy and Roundup -0 5 ch season Envoy and Roundup produced no significant 0.5 c Besides goatgrass, the only non‐native species recorded in the plots were the annual grass, Bromus produced no significant reduction relative to controls 06 hordeaceus, and the annual forb, Lactuca serriola, and both species were a minor component of the reduction relative to controls. E l li ti f M d E w M L L E d l -0.6 community with an average of 0.4% and 0.06% cover, respectively. B. hordeaceus increased on hand‐ Early‐season application of FusM Hand FusE Mow EnvM FusL EnvL EnvE ound ntrol pulled plots , late‐season Envoy plots, and Roundup plots relative to plots that were treated early with Envoy resulted in damage to Fus Ha Fu M Env Fu En En Rou Cont grass‐specific herbicide (data not shown). B. hordeaceus was susceptible to all three herbicides, but goatgrass, followed by partial C treatment grass specific herbicide (data not shown). B. hordeaceus was susceptible to all three herbicides, but sets seed in April and May so it was unaffected by the late season applications recovery. Late‐season treatment sets seed in April and May, so it was unaffected by the late season applications. application of all herbicides Figure 1. Change in barbed goatgrass frequency after one and two failed to prevent at least some years of treatment. Error bars represent SEM. Solid lines below the failed to prevent at least some viable seed production bars group treatments that are not significantly different in 2010 by viable seed production. Tukey’s HSD test at α=0.05. Abbreviations: EnvE, Envoy early season; Plate 1. Barbed goatgrass invasion front in a Plate 2. Experimental plots in summer 2009, after the EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusilade serpentine grassland at the McLaughlin Reserve first season of treatment early season; FusM, Fusilade mid season; FusL, Fusilade late season; Hand, hand pull; Round, Roundup. Eff t ti Early‐season herbicide treatments were applied in mid‐March, three to four weeks before flower Effects on native grasses initiation. Mid‐season herbicide treatments were applied in early May as inflorescences were beginning Both grass specific herbicides caused damage to native perennial grasses but virtually all of these to extend from the sheath. Late‐season herbicide treatments were applied at the end of May, when all Both grass‐specific herbicides caused damage to native perennial grasses, but virtually all of these d ft th d f li ti Lt E lt di i goatgrass had flowered, and most were showing signs of early seed development (a small, soft, green grasses recovered, even after the second year of application. Late‐season Envoy resulted in an increase goatgrass had flowered, and most were showing signs of early seed development (a small, soft, green embryo was apparent) Mowing occurred at the peak of flowering in late May before any seed in total bunchgrass frequency relative to controls (data not shown), whereas all other treatments embryo was apparent). Mowing occurred at the peak of flowering in late May before any seed development was evident and was done with gas powered string trimmers at a height of approximately produced changes that were statistically indistinguishable from controls. There was no suggestion that development was evident, and was done with gas‐powered string trimmers at a height of approximately 2 cm Hand pulling occurred in mid May bunchgrass frequency was reduced by any treatment, with the possible exception of early‐season 2 cm . Hand pulling occurred in mid‐May. Envoy. Individually, neither N. pulchra nor P. secunda was negatively affected by treatments (Fig. 2, Plate 6 Early‐season Fusilade plot in early summer Plate 5 Late season Envoy plot after two years of Plate 5), except that N. pulchra was completely eliminated by Roundup (P. secunda escaped this effect Plate 6. Early‐season Fusilade plot in early summer 2009 showing growth of N jepsonii and H virgata Plate 5. Late season Envoy plot after two years of treatment showing persistence of N pulchra Herbicides were applied using a spray to wet technique with a backpack sprayer using the Plate 5), except that N. pulchra was completely eliminated by Roundup (P. secunda escaped this effect because it was dormant during the late‐season herbicide applications) The native annual grass V 2009 showing growth of N. jepsonii and H. virgata. treatment showing persistence of N. pulchra. recommended spot‐spray rate for Fusilade II, the near‐maximum spot‐spray rate for Envoy +, and a because it was dormant during the late‐season herbicide applications). The native annual grass, V. microstachys also was not negatively impacted by any of the treatments (Fig 2) For V microstachys Conclusions recommended spot spray rate for Fusilade II, the near maximum spot spray rate for Envoy , and a 1 6% solution for Roundup (Table 1 Plate 4) Envoy and Fusilade were mixed with 0 33 oz/gal of a microstachys, also was not negatively impacted by any of the treatments (Fig. 2). For V. microstachys, hand pulling produced a benefit relative to early application of Envoy but neither treatment differed Conclusions 1.6% solution for Roundup (Table 1, Plate 4). Envoy and Fusilade were mixed with 0.33 oz/gal of a modified vegetable oil/silicone surfactant (Syl‐tac) hand pulling produced a benefit relative to early‐application of Envoy, but neither treatment differed f t l modified vegetable oil/silicone surfactant (Syl‐tac). 4 from controls. 10 15 • Fusilade applied early or mid‐season and Envoy applied mid‐season controls barbed goatgrass, 4 a 10 ver a 15 r while sparing native perennial grasses and forbs. Early‐season Envoy failed to control goatgrass. er a 8 cov over while sparing native perennial grasses and forbs. Early season Envoy failed to control goatgrass. Table 1. Application rates used for herbicide treatments. 3 cov a 8 ent c nt co • Application of grass‐specific herbicides early in the season provides the most benefit to native Table 1. Application rates used for herbicide treatments. Herbicide Mix concentration Approximate per‐acre rate ent c a a a erce 10 cen forbs (probably because of their early release from competition), but may set back native grasses, oz concentrate/gallon oz concentrate/acre erce a ab ab 6 s pe ab perc which benefit more from applications later in the season when they have set seed or are nearer to oz concentrate/gallon oz concentrate/acre E 08 64 80 2 a pe chys ab hra dormancy. Early‐season application can also provide control of other non‐native annual grasses, Envoy + 0.8 64‐80 unda 4 stac ab ulch dormancy. Early season application can also provide control of other non native annual grasses, such as B hordeaceus that mature earlier than goatgrass F il d II 0 75 60 75 ecu cros ab ab ab 5 a pu such as B. hordeaceus, that mature earlier than goatgrass. Fusilade II 0.75 60‐75 1 oa s ab ab ab 2 a mi ab ab ab b sell • Mowing provides acceptable goatgrass control, but less benefit to native forbs. d Po ab 2 ulpia ab b Nass Lt li ti fR d f il dt t l t li i td N lh d d d Roundup Pro 2.1 168‐210 b Vu b N • Late‐season application of Roundup failed to control goatgrass, eliminated N. pulchra, and reduced h f i f b h ill i l i h i f li i und usL Mow nvL sM nvM and trol nvE usE 0 and und usL nvL sM Mow usE trol vM nvE 0 usL sM usE nvL and Mow trol vM nvE und 0 the cover of some native forbs that were still actively growing at the time of application. Roun Fus Mo Env Fus Env Han Contr Env Fus t t t Han Roun Fus Env Fus Mo Fus Contr Env Env Fus Fus Fus Env Han Mo Contr Env Env Roun • For all treatments significant goatgrass cover remains after two years of treatment Outside of treatment treatment treatment • For all treatments, significant goatgrass cover remains after two years of treatment. Outside of this study our experience suggests that five to six years of hand pulling is necessary to deplete the References Fi 2 P t f th ti ft t ft t t E b t SEM L tt this study, our experience suggests that five to six years of hand pulling is necessary to deplete the db k T id l ti f h bi id it lti t t t h ld Figure 2. Percent cover of three native grasses after two years of treatment. Error bars represent SEM. Letters b th b t t t th t ti ifi tl diff tb Tk ’ HSD t t t 0 05 Abb i ti seed bank. To avoid selection for herbicide resistance, a multi‐year treatment program should b i ih ib d fi d l h bi id ih i DiTomaso JM KL Heise GB Kyser AM Merenlender and R J Keiffer 2001 Carefully timed burning above the bars group treatments that are not significantly different by Tukey’s HSD test at α=0.05. Abbreviations: E E E l E M E id E L E lt F E F il d l F M begin with prescribed fire and alternate herbicide use with mowing. DiTomaso, J.M., K.L. Heise, G.B. Kyser , A.M. Merenlender , and R.J. Keiffer . 2001. Carefully timed burning can control barb goatgrass California Agriculture 55(6): 47 53 EnvE, Envoy early season; EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusilade early season; FusM, F il d id F L F il d lt H dh d ll R dR d can control barb goatgrass. California Agriculture 55(6): 47‐53. Fusilade mid season; FusL, Fusilade late season; Hand, hand pull; Round, Roundup.
Transcript of CtlControl off bbdbarbed goatgrassggt (AilAegilopsgpti i ... · Mti tdb th d f fll /lt titt tt fi...
C t l f b b d t (A il t i i li ) i ti l dControl of barbed goatgrass (Aegilops triuncialis) in serpentine grasslandsControl of barbed goatgrass (Aegilops triuncialis) in serpentine grasslandsg g ( g p ) p gPaul A Aigner and Rhett J Woerly University of California Davis Donald and Sylvia McLaughlin Reserve Lower Lake CAPaul A. Aigner and Rhett J. Woerly, University of California Davis, Donald and Sylvia McLaughlin Reserve, Lower Lake, CA
ff i f bSerpentine grasslands are known for being relatively free of the invasive species that typify other Effects on native forbsCalifornia grasslands. Recently the special status of serpentine grasslands as strongholds of native plant diversity has been threatened by the spread of barbed goatgrass (Aegilops triuncialis), a Eurasian annual Native forbs were especially diverse in the study area, with 51 species recorded across all plots, and ay y p g g ( g p ),that is unique in its tolerance of serpentine soils (Plate 1). Carefully timed prescribed fire, especially
Native forbs were especially diverse in the study area, with 51 species recorded across all plots, and a median of 13 species per plot As a group native forbs increased in frequency dramatically on hand‐that is unique in its tolerance of serpentine soils (Plate 1). Carefully timed prescribed fire, especially
applied over two consecutive years has been shown to reduce goatgrass while benefitting many nativemedian of 13 species per plot. As a group, native forbs increased in frequency dramatically on hand‐pulled early season Fusilade and early season Envoy plots (Fig 3A) All other treatments showed aapplied over two consecutive years, has been shown to reduce goatgrass while benefitting many native
species (DiTomaso et al 2001 ) At the McLaughlin Reserve in the inner North Coast Range of Californiapulled, early‐season Fusilade, and early‐season Envoy plots (Fig. 3A). All other treatments showed a trend toward increasing native forb frequency but none differed statistically from controls Of thespecies (DiTomaso et al. 2001 ). At the McLaughlin Reserve in the inner North Coast Range of California,
we found prescribed fire cannot be applied for two consecutive years because the low productivity oftrend toward increasing native forb frequency, but none differed statistically from controls. Of the i ht f b i ith ll l t f 1% t h d i ith lwe found prescribed fire cannot be applied for two consecutive years, because the low productivity of
ti l d t d t f l b ild i th d S ti l deight forb species with an average cover across all plots of >1%, two showed increases with early‐
serpentine grasslands prevents adequate fuel build up in the second year. Some serpentine grasslands d i h fi ill ll
season application of grass specific herbicides (Fig. 3B&C). Navarretia jepsonii, a serpentine endemic are so unproductive that fire will not carry at all. annual, had higher cover on early‐season Fusilade plots compared to controls, mowing, and all of the
M ti t d b th d f f ll / lt ti t t t t fi l t d i t t t flate‐season herbicide plots (Fusilade, Envoy, and Roundup). N. jepsonniimay have been negatively
Motivated by the need for a follow up/alternative treatment to fire, we evaluated nine treatments for p ( , y, p) j p y g y
affected by Roundup, as it was still actively growing at the time of application. Holocarpha virgata, a their effectiveness controlling barbed goatgrass and for restoring native species cover and diversity:
y p, y g g pp p g ,summer annual, had higher cover on early‐season Fusilade and Envoy plots relative to controls.
two grass‐specific herbicides —fluazifop [Fusilade II ] and clethodim [Envoy +]—applied before summer annual, had higher cover on early season Fusilade and Envoy plots relative to controls.
goatgrass flowering (early‐season), at flower initiation (mid‐season), and at early seed development 80.5 6g g g ( y ), ( ), y p(late‐season), a broad‐spectrum herbicide (glyphosate) applied late‐season, mowing , and hand pulling. ve
r a2009Plate 3 Control plot summer 2009 Plate 4 Early‐season herbicide application March erA B C( ), p (g yp ) pp , g , p g
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In fall of 2007 we established a grid of 100, 2m x 2m plots with 2‐m wide buffers between plots in a goatgrass4
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20092010
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frequency of barbed goatgrass, native forbs, native bunchgrasses (almost exclusively Nassella pulchra Envoy resulted in reduced goatgrass frequency relative to
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treatmentand Poa secunda), and other annual grasses (Bromus hordeaceus and Vulpia microstachys) in 25, 27‐mm goatgrass frequency relative to controls (Fig 1) Mid season
treatment-0.1ra treatment treatmentFigure 3 (A) Change in native forb frequency after one and two years of treatment Error bars represent SEM
diameter circular subplots within each plot. In early May 2010, we made visual estimates of cover of all controls (Fig. 1). Mid‐season Fusilade hand pulling and tg Figure 3. (A) Change in native forb frequency after one and two years of treatment. Error bars represent SEM.
Solid lines below the bars group treatments that are not significantly different in 2010 by Tukey’s HSD test atspecies within a 1‐m2 frame at the center of each plot. Fusilade, hand pulling, and
l F il d h d-0.2oa
Solid lines below the bars group treatments that are not significantly different in 2010 by Tukey s HSD test at α=0 05 (B & C) Percent cover of two native forbs after two years of treatment Error bars represents SEMp p
early‐season Fusilade showed go
α=0.05. (B & C) Percent cover of two native forbs after two years of treatment. Error bars represents SEM. Letters above the bars group treatments that are not significantly different by Tukey’s HSD test at α=0 05the best performance, reducing
0 3n g Letters above the bars group treatments that are not significantly different by Tukey s HSD test at α=0.05.
Abbreviations: EnvE Envoy early season; EnvM Envoy mid season; EnvL Envoy late season; FusE Fusilade earlygoatgrass frequency by 66%, -0.3 in Abbreviations: EnvE, Envoy early season; EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusilade early
season; FusM Fusilade mid season; FusL Fusilade late season; Hand hand pull; Round Roundup62% , and 52% respectively geBarbed goatgrass
season; FusM, Fusilade mid season; FusL, Fusilade late season; Hand, hand pull; Round, Roundup., p y
from the pre‐treatment -0.4ng Effects on other non nativesg g
pfrequency of about 0.7. Early‐ an Effects on other non‐nativesfrequency of about 0.7. Earlyseason Envoy and Roundup -0 5chseason Envoy and Roundup produced no significant
0.5c Besides goatgrass, the only non‐native species recorded in the plots were the annual grass, Bromusproduced no significant reduction relative to controls 0 6
hordeaceus, and the annual forb, Lactuca serriola, and both species were a minor component of the reduction relative to controls. E l li ti f M d E w M L L E d l
-0.6 community with an average of 0.4% and 0.06% cover, respectively. B. hordeaceus increased on hand‐Early‐season application of
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t p p , y p , p p p ygrass‐specific herbicide (data not shown). B. hordeaceus was susceptible to all three herbicides, but
goatgrass, followed by partial
C
treatmentgrass specific herbicide (data not shown). B. hordeaceus was susceptible to all three herbicides, but sets seed in April and May so it was unaffected by the late season applications
recovery. Late‐season treatment sets seed in April and May, so it was unaffected by the late season applications.y
application of all herbicides Figure 1. Change in barbed goatgrass frequency after one and two ppfailed to prevent at least some
g g g g q yyears of treatment. Error bars represent SEM. Solid lines below the failed to prevent at least some
viable seed productiony pbars group treatments that are not significantly different in 2010 by viable seed production. g p g y yTukey’s HSD test at α=0.05. Abbreviations: EnvE, Envoy early season;
Plate 1. Barbed goatgrass invasion front in a Plate 2. Experimental plots in summer 2009, after the y , y y ;
EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusiladeserpentine grassland at the McLaughlin Reserve first season of treatment
, y ; , y ; ,early season; FusM, Fusilade mid season; FusL, Fusilade late season; y ; , ; , ;Hand, hand pull; Round, Roundup.
Eff t ti, p ; , p
Early‐season herbicide treatments were applied in mid‐March, three to four weeks before flower Effects on native grassesinitiation. Mid‐season herbicide treatments were applied in early May as inflorescences were beginning
Both grass specific herbicides caused damage to native perennial grasses but virtually all of thesepp y y g g
to extend from the sheath. Late‐season herbicide treatments were applied at the end of May, when all Both grass‐specific herbicides caused damage to native perennial grasses, but virtually all of these
d ft th d f li ti L t E lt d i ipp y,
goatgrass had flowered, and most were showing signs of early seed development (a small, soft, greengrasses recovered, even after the second year of application. Late‐season Envoy resulted in an increase
goatgrass had flowered, and most were showing signs of early seed development (a small, soft, green embryo was apparent) Mowing occurred at the peak of flowering in late May before any seed
in total bunchgrass frequency relative to controls (data not shown), whereas all other treatments embryo was apparent). Mowing occurred at the peak of flowering in late May before any seed development was evident and was done with gas powered string trimmers at a height of approximately
produced changes that were statistically indistinguishable from controls. There was no suggestion that development was evident, and was done with gas‐powered string trimmers at a height of approximately 2 cm Hand pulling occurred in mid May
bunchgrass frequency was reduced by any treatment, with the possible exception of early‐season 2 cm . Hand pulling occurred in mid‐May.
g q y y y , p p yEnvoy. Individually, neither N. pulchra nor P. secunda was negatively affected by treatments (Fig. 2, Plate 6 Early‐season Fusilade plot in early summerPlate 5 Late season Envoy plot after two years ofy y, p g y y ( g ,Plate 5), except that N. pulchra was completely eliminated by Roundup (P. secunda escaped this effect
Plate 6. Early‐season Fusilade plot in early summer 2009 showing growth of N jepsonii and H virgata
Plate 5. Late season Envoy plot after two years of treatment showing persistence of N pulchra
Herbicides were applied using a spray to wet technique with a backpack sprayer using the Plate 5), except that N. pulchra was completely eliminated by Roundup (P. secunda escaped this effect because it was dormant during the late‐season herbicide applications) The native annual grass V
2009 showing growth of N. jepsonii and H. virgata.treatment showing persistence of N. pulchra.pp g p y q p p y g
recommended spot‐spray rate for Fusilade II, the near‐maximum spot‐spray rate for Envoy +, and abecause it was dormant during the late‐season herbicide applications). The native annual grass, V. microstachys also was not negatively impacted by any of the treatments (Fig 2) For V microstachys Conclusionsrecommended spot spray rate for Fusilade II, the near maximum spot spray rate for Envoy , and a
1 6% solution for Roundup (Table 1 Plate 4) Envoy and Fusilade were mixed with 0 33 oz/gal of amicrostachys, also was not negatively impacted by any of the treatments (Fig. 2). For V. microstachys, hand pulling produced a benefit relative to early application of Envoy but neither treatment differed
Conclusions1.6% solution for Roundup (Table 1, Plate 4). Envoy and Fusilade were mixed with 0.33 oz/gal of a modified vegetable oil/silicone surfactant (Syl‐tac)
hand pulling produced a benefit relative to early‐application of Envoy, but neither treatment differed f t lmodified vegetable oil/silicone surfactant (Syl‐tac).
4from controls.
1015 • Fusilade applied early or mid‐season and Envoy applied mid‐season controls barbed goatgrass, 4
a
10
ver a
15
r
pp y y pp g g ,while sparing native perennial grasses and forbs. Early‐season Envoy failed to control goatgrass.
er
a
8cov
over
while sparing native perennial grasses and forbs. Early season Envoy failed to control goatgrass.Table 1. Application rates used for herbicide treatments.
3cov
a8
ent c
nt c
o • Application of grass‐specific herbicides early in the season provides the most benefit to native Table 1. Application rates used for herbicide treatments.
Herbicide Mix concentration Approximate per‐acre rate ent c a
aa er
ce10cen forbs (probably because of their early release from competition), but may set back native grasses,
oz concentrate/gallonpp p
oz concentrate/acre erce a
ab ab 6s pe
abperc
which benefit more from applications later in the season when they have set seed or are nearer to oz concentrate/gallon oz concentrate/acre
E 0 8 64 802a
pe
chys ab
hra
pp ydormancy. Early‐season application can also provide control of other non‐native annual grasses,Envoy + 0.8 64‐80
unda
4stac
abulch
dormancy. Early season application can also provide control of other non native annual grasses, such as B hordeaceus that mature earlier than goatgrass
F il d II 0 75 60 75
ecu
cros ab ab ab5a pu such as B. hordeaceus, that mature earlier than goatgrass.
Fusilade II 0.75 60‐75 1
oa s ab ab
ab 2a m
i
ab ab ab bsell • Mowing provides acceptable goatgrass control, but less benefit to native forbs.
d
Po ab 2
ulpi
a ab ab
bNas
s
L t li ti f R d f il d t t l t li i t d N l h d d dRoundup Pro 2.1 168‐210 b Vu bN • Late‐season application of Roundup failed to control goatgrass, eliminated N. pulchra, and reduced
h f i f b h ill i l i h i f li i
und
usL
Mow nvL sM nvM and trol
nvE
usE
0
and
und
usL
nvL sM Mow usE tro
lvM nv
E
0
usL sM usE nvL
and
Mow trol
vM nvE
und
0 the cover of some native forbs that were still actively growing at the time of application.
Roun
Fus Mo
Env Fus Env HanCon
trEnv Fus
t t t
HanRou
nFus Env Fus MoFus
Contr
Env EnvFus Fus Fus Env Han MoCon
trEnv EnvRou
n
• For all treatments significant goatgrass cover remains after two years of treatment Outside oftreatment treatmenttreatment • For all treatments, significant goatgrass cover remains after two years of treatment. Outside of this study our experience suggests that five to six years of hand pulling is necessary to deplete theReferences Fi 2 P t f th ti ft t f t t t E b t SEM L tt this study, our experience suggests that five to six years of hand pulling is necessary to deplete the
d b k T id l ti f h bi id i t lti t t t h ldFigure 2. Percent cover of three native grasses after two years of treatment. Error bars represent SEM. Letters b th b t t t th t t i ifi tl diff t b T k ’ HSD t t t 0 05 Abb i ti seed bank. To avoid selection for herbicide resistance, a multi‐year treatment program should
b i i h ib d fi d l h bi id i h iDiTomaso J M K L Heise G B Kyser A M Merenlender and R J Keiffer 2001 Carefully timed burningabove the bars group treatments that are not significantly different by Tukey’s HSD test at α=0.05. Abbreviations: E E E l E M E id E L E l t F E F il d l F M begin with prescribed fire and alternate herbicide use with mowing.DiTomaso, J.M., K.L. Heise, G.B. Kyser, A.M. Merenlender, and R.J. Keiffer. 2001. Carefully timed burning
can control barb goatgrass California Agriculture 55(6): 47 53EnvE, Envoy early season; EnvM, Envoy mid season; EnvL, Envoy late season; FusE, Fusilade early season; FusM, F il d id F L F il d l t H d h d ll R d R dcan control barb goatgrass. California Agriculture 55(6): 47‐53. Fusilade mid season; FusL, Fusilade late season; Hand, hand pull; Round, Roundup.
