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Home , Bothriochloa, Bothriochloa bladhii, Bouteloua chondrosioides, Old World

USDA Department of Agriculture - Field Guide for Managing Yellow and Caucasian (Old ) Bluestems in the Southwest

Forest Southwestern Service Region TP-R3-16-36 October 2018 Cover Photos Top left — Yellow bluestem; courtesy photo by Max Licher, SEINet Top right — Yellow bluestem panicle; courtesy photo by Billy Warrick; Soil, Crop and More Information Lower left — Caucasian bluestem panicle; courtesy photo by Max Licher, SEINet Lower right — Caucasian bluestem; courtesy photo by Max Licher, SEINet

Authors Karen R. Hickman — Professor, State University, Stillwater OK Keith Harmoney — Range Scientist, KSU Ag Research Center, Hays KS Allen White — Region 3 Pesticides/Invasive Species Coord., Forest Service, Albuquerque NM

Citation: USDA Forest Service. 2018. Field Guide for Managing Yellow and Caucasian (Old World) Bluestems in the Southwest. Southwestern Region TP-R3-16-36, Albuquerque, NM.

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Printed on recycled paper Yellow bluestem ( (L.) Keng) Caucasian bluestem ( (Retz.) S.T. Blake, synonym: B. caucasica (Trin.) C.E. Hubb.) Grass family (), tribe

Yellow and Caucasian bluestems are introduced identification of the two OWB species difficult in the bunchgrass species that are becoming invasive in spring. Positive identification generally can only be made southwestern States after successfully invading the Central after panicles have developed. Resources for identifying and Southern . This field guide serves as the these two bluestem species can be found in the Photo U.S. Forest Service’s recommendations for management of Image Libraries subsection at the end of this document. yellow and Caucasian bluestems in forests, woodlands, OWBs are native to , , and . They rangelands, desert, and desert scrub associated with its were first introduced into the U.S. in the early 1900s and Southwestern Region. The Southwestern Region covers have been planted widely throughout the Central and and New , which together have 11 national Southern Great Plains for forage and for erosion control in forests. The Region also administers 4 national grasslands disturbed areas such as roadside rights-of-way (ROWs). located in northeastern , western Oklahoma, OWB seed is readily obtained from many seed companies. and the panhandle. Growth Characteristics Description Both OWB species – Yellow bluestem () and • Are warm-season, perennial bunchgrasses that are Caucasian bluestem (Bothriochloa bladhii) are perennial relatively shade-intolerant; typically, they have mid-grasses that belong to a group of non-native bluestems rhizomes (underground stems) and stolons (above- collectively referred to as Old World bluestems (OWBs). ground stems) under close grazing or cutting. Yellow The term Old World bluestem is a shared common name bluestem has a more rhizomatous growth form for approximately 65 species in the closely related genera relative to Caucasian bluestem’s bunchgrass of Bothriochloa Kuntze, Stapf, and (caespitose) growth form. Although the early growth Willemet. B. bladhii is used synonymously form of yellow bluestem is an erect bunchgrass, with B. caucasica, which is nearly similar in morphology older stands tend to form a sod. but has an uncertain . • Produce spindly looking, flowering culms/tillers that Common names for yellow bluestem include King Ranch are 2–4 feet tall, depending on moisture. The two bluestem and Turkestan beardgrass; the most common species have reproductive and vegetative cultivars are King Ranch, Plains, Ganada, WW–Spar, and culms/tillers that are roundish with varying amounts WW–Iron Master. Caucasian bluestem is also called of hair; leaves typically are 0.25 to < 0.5 inches wide Australian beardgrass (or bluestem), forest bluegrass, and and 8-12 inches in length, flat or folded. purple plume grass. It has a single cultivar named WW-B. • Can initiate rapid growth in the summer and Dahl. OWB cultivars were developed from introduced reproduce earlier than native species, which actually germplasm and have been selected for different disease deters grazing. and insect threats, climates, and soil-site conditions. • Produce reddish-purple inflorescences; some cultivar Yellow bluestem derives its name from its yellow-green inflorescences may turn fawn to white-colored at culms and leaves. Caucasian bluestem has dense blue- maturity. Yellow bluestem’s inflorescence is a fan or green leaves, and some can be strongly aromatic. finger-like panicle; Caucasian bluestem has a panicle Close similarity to native bluestems makes early that is pyramidal or evergreen tree-shaped.

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• Readily germinate from seed and establish Site/Distribution reproducing populations within one growing season; OWBs can infest both disturbed and non-disturbed sites; such features are highly desirable for hay production. however, they tend to establish more readily on disturbed Both OWB species are prolific seed producers, and sites. The two species can adapt to highly calcareous soils extensive seed banks can develop in soil. with high pH but do well on any well-drained soil. Yellow bluestem is best adapted for sandy loam to clay loam soils. Ecology In general, OWBs have relatively little cold tolerance, Impacts/Threats which makes them unable to withstand environment s with Once established, OWBs can be highly invasive and have extended periods of freezing winter temperatures. the potential to form biodiversity-inhibiting monocultures Caucasian bluestem is more tolerant to freezing and tends that can transform grassland vegetation at the community to occur in more northerly climes in the Midwest. Yellow and ecosystem levels of organization. OWB monocultures bluestem is more common in the southern U.S. and is lack the necessary variety in structure, seasonality of growth, winter-hardy in the Central Great Plains only to about 40 º and nutritional availability required to sustain a diverse N latitude. Both OWBs are found throughout Arizona and fauna. Floral diversity may be impacted directly by OWBs New Mexico, although Caucasian bluestem is relatively through physical displacement, competition, etc. Habitats of uncommon at this point in time. some Threatened and Endangered (T&E) species in particular can be threatened by OWBs. In combination with Spread other less desirable non-native grass species such as Sites planted or invaded by OWBs serve as the primary Lehmann lovegrass (Eragrostis lehmanniana), OWBs may source for further spread onto disturbed and non-disturbed form a complex that can act similarly to a monoculture. sites. In the Southwest, OWBs generally migrate away from infested roadsides or other disturbed areas in an Pastures and grasslands invaded by OWBs support fewer advancing front across pastures or native grasslands. If insects (a vital part of the food chain) as they lack forbs, unassisted, OWB seed has relatively limited dispersion which typically host more insects than wind-pollinated and will mostly establish seedlings close to parent plants. grasses. The reduction in forbs may particularly impact However, seeds readily disperse via mowing operations in native pollinators such as bees and butterflies. In addition, ROWs, vehicular traffic, flowing water, animals, and the loss in insect activity could ultimately lead to lower numbers and diversity of songbirds. winds moving across open terrain. Growth of stolons and rhizomes may also contribute to spread on a local basis. OWB infestations can alter carbon:nitrogen (C:N) ratios in soil and the composition of soil microbial communities, In the Southwest, State and county highway departments including arbuscular mycorrhizae. Growth of native have used OWBs in seeding ROWs for erosion control. species may be inhibited by these changes in soil properties. Use of OWBs was encouraged in the 1980s for In addition, a recent study has found that an allelopathic Conservation Reserve Program (CRP) lands in Oklahoma, toxin produced by yellow bluestem can reduce reproduction, the Texas panhandle, and eastern New Mexico. Yellow growth, and survival of native bluestems. bluestem was also planted during the Dust Bowl era on lands acquired by the Federal government for Heavy OWB infestations in pastures or native grassland may rehabilitation under the Bankhead-Jones Farm T enant Act require changes in grazing management practices. Mature of 1937 . Su ch widespread planting s ha ve enabl ed OWB s patches of OWBs are typically avoided by grazing animals, to mov e northward into Nebraska and Missour i fro m large which can cause accumulation of residual dead standing populations already present in more southerly States. material that is also avoided. High levels of dry matter accumulated in these patches may be prone to wildfire.

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Invasive Features • Use power washers or air compressors with a blow Both OWB species are quickly established, produce large gun attachment to remove seed from vehicles after numbers of seed, and can tolerate severe drought, heavy going through OWB-infested areas. grazing, fire, and a limited amount of winter freezing. • If re-seeding an area, do not use seed obtained from Many of the characteristics that make OWBs desirable for equipment that has also been used to harvest and/or planting also promote invasion of pastures and native process OWBs. grasslands. For example, both OWBs are tolerant to drought and grazing; however, selecting these traits for To manage OWBs, the following actions should be forage production has increased their invasiveness. performed:

The most common use for OWBs is cattle forage, although • Detect, eradicate, or at least contain newly cattle often find them less palatable than warm-season established OWB populations as early as possible, native grasses. Consequently, animals may avoid grazing especially along roadways and waterways. In areas OWBs in favor of native plants thereby giving OWBs a where eradication or containment of these species competitive advantage. are no longer feasible, efforts should be made to control their rate of spread.

Management • Report and map known OWB populations. Keep Considerable information exists in regard to planting and annual records on reported infestations. managing OWBs for various agronomic purposes such as • Develop a specific action plan to meet goals and grazing, forage production, soil erosion prevention, objectives for established OWB infestations, which reclamation, etc. However, there is much less experience may emphasize eradication of new OWB infestations and information available about controlling these grasses in sensitive areas such as T&E species habitat, travel in areas where preservation of native plant communities is corridors, etc. a primary management objective. Restoration of pastures or native grasslands dominated by OWBs has proven to be • Implement a plan for monitoring and follow-up exceedingly difficult if not impossible. Studies conducted treatment of missed OWB plants and seedlings. in the Great Plains with different OWB control methods Also, monitor recovery of desirable native plant have shown varying degrees of success. Results from these species following control efforts. studies indicate that an integrated management approach Management Options generally improves the efficacy of herbicide control. Table 1 summarizes management options for common OWBs are most effectively managed by preventing their situations involving yellow and Caucasian bluestems. spread. Preventative measures that can be taken include, Further details on these management options are explained but are not limited to: below. Choice of control method(s) for OWBs depends on • Do not plant OWB seed for forage, erosion control, many local factors including extent of infestation, current reclamation, or other purposes. land use, and site conditions (terrain, accessibility, microclimate, presence of non-target flora and fauna, etc.). • Do not mow OWB-infested areas in ROWs or other Other considerations include treatment effectiveness and corridors of transport once seedheads have started to cost, time needed to achieve control, and whether the form. management objective is eradication, containment, or • Do not feed grass hay from unknown sources or slowing the spread of infestation. More than one control from ROWs. method may be needed for a particular site.

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Table 1. Management options*

Site Physical Control Cultural Control Biological Control Chemical Control

Roadsides, Disk or plow tillable non- Test seed, forage, mulch, and Classical biocontrol Use truck or tractor-mounted fence lines, crop areas. fill materials for OWB seed. agents are unavailable. spraying equipment to or non-crop broadcast treat. Wash Use late season, long-term Use native grass species or areas underneath vehicle after mowing to reduce OWB other desirable plant species application to prevent seed growth in spring. Since when reseeding rights-of-way. spread. movement of seed can Avoid driving vehicles and increase infestations along equipment through infested ROWs, do not mow once areas. Decontamination OWB flowering heads have procedures should be started to form. implemented if travel through Burning used alone is not these areas is necessary. recommended as it will likely result in increased OWB densities; consider combining burning with herbicide spraying.

Rangelands, Disk or plow if OWBs are Test seed, forage, mulch, and To reduce OWB biomass Use truck or tractor-mounted pastures, or in previously tilled areas. fill materials for OWB seed; and fuel load, graze in spraying equipment to riparian use pellets for horses in the spring when OWBs broadcast treat. In areas Use late season, long-term corridors backcountry areas. may be more palatable difficult to access, an ATV- mowing to reduce OWB or graze standing residue mounted sprayer or backpack growth in spring. Since Avoid driving vehicles and in the fall-winter. Use a unit may be the most movement of seed can equipment through infested protein supplement with practical application method . increase infestations along areas. Decontamination fall or winter grazing. Wash underneat h vehicl e after ROWs, do not mow once procedures should be application to prevent seed OWB flowering heads have implemented if travel through Classical biocontrol spread. started to form. these areas is necessary. agents are unavailable. Burning used alone is not Where feasible, consider recommended as it will reseeding areas with native likely result in increased grasses or other desirable OWB densities; consider plant species following OWB combining burning with control actions. herbicide spraying.

Wilderness, Hand pulling or digging same as above same as above Use backpack or hand-held other natural may aid in control. Pull sprayers. If allowed, vehicle areas, and/or when soil is moist and sprayers may be used to small remove as much root stock broadcast spray thick OWB infestations as possible; wear gloves for stands. Wash underneat h pulling. vehicle after a pplication to prevent seed spread.

* Choice of a particular management option must be in compliance with existing regulations for the land resource.

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Physical Control sustained mowing done annually in September can reduce Physical methods used to control OWBs normally have to OWB cover on a long -term basis as compared to un -mown be repeat ed and must be timed properly with seedhead areas or areas mowed in March or June . Mowing is more formation to be effective. Mowing and burni ng used alone effectiv e if comb ined with pre or post-herbicid e treatments . do not control OWBs and discontinuing them can re- Prescribed Fire establish OWB densities to pretreatment level s or worse. OWBs rapidly recover after fire and may return at greater Thus, an integrated appro ach that combines mowing or densities than b efore. Thus, burning is not recommended as a burning wit h herbicide applicatio n should be used. single or stand-alone contr ol method. A s compared to

Manual Methods mowing, burning is better ab le to reduce OWB cover. Hand rem oval – For isolated or patchy plants, hand pulling Prescribed fire applie d past the boot stage but prior to full seed productio n has shown the greatest potentia l for or digging to remove top growth and root s are the most effective techniques. Hand removal of OWBs can be reducing OWB co ver. complicated as these species can form mats. Manual Cultural Control methods may be combined with herbicide application when To prevent O WB seed mo vement, sanitary measures for OWB populations are relatively small or isolated. vehicles, equipment, and livestock should be implemented.

Mechanical Methods Only clean vehicles and equipment should be allowed to Note – If using machinery t o manage OWBs, the equipment enter un-infested areas . Seed and materials used for plantin g, should be cleaned after use in infested areas to p revent mulch, animal forage, or fill should be tested for presence of transfer of seed into un-infested areas. OWB s eed; pe llets may be used for horses in backcountry areas. Tillage – Tillage with a disk or plow may be used to remove

OWBs fro m previously tilled areas such as old cropland; Public education about the use of non-native grasses, such as however , any newly tilled are a will need to be planted with OWBs, and their impacts o n ecosystem s is essential for desirable vegetation . Better resu lts with tillage may be changing seeding practices. Agencies and landowner s should achieved when conditions are dry enough to desiccate OWB collaborate in promoting use of native or other desirable root fragments . Repeated shallow tillage with implements species rather t han OWBs for reseeding areas disturbed by such as a rotary or disc harrow may prevent deep ly mining, fire, overgrazing, or road constru ction . In the embedded seeds from coming to the soil surface for Southwest, species such as Arizona cottontop ( Digitaria possible germination . Nonetheless , tillag e without follow-up californica), sideoats grama ( curtipendula), control measur es can increase OWB densit ies by breaking sprucetop grama (Bouteloua chondrosioides ), plains up root masses and scatterin g the fragments. It also exposes bristlegrass (Setaria macrostachya), and other native species bare soil, which can become infested b y OWBs . See adapted to relatively lower elevations may be considered. Integrat ed Control M ethods at the end of this sectio n for information on integrated approaches using tillage. Biological Control Grazing Mowing – Mowing along ROWs has the potential to spread By itself, g razing is inadequate to eradicate or control OWB seed and can lead to OWB dominance within ROWs. OWBs as these species are highly tolerant of close grazing Therefore, infested ROWs and other transport corridors or defoliation. OWBs are palatable when young and may should not be mowed once OWB flowering heads have have equal or greater forage quality in the early growing started to form, as this will move seed into un-infested ar eas. season as compared to some native species. However, OWB However, one study conducted in Oklahoma found that plants generally mature more quickly than most native

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warm-season grasses and correspondingly become less treatment may be used. Placement of protein, mineral, or salt palatable. Burning and mowing old vegetation can increase in troughs, tanks, tubs, or blocks within areas of standing OWB palatability, and some cultivars may be m ore palatable dead OWBs and then eventually moving these feedstuff to livestock than others. materials to other affected sites can provi de sufficien t trampling for reduction of clumps and mounds while also Although OWBs are usually avoided by grazing animals in benefitting livestock distribution. favor of native vegetation during periods of adequate moisture, they can be highly selected by grazers during It is not known whether OWB seed ingested by grazing drought periods. OWBs retain green leaf material longer animals remains viable after passing through the animal; than some native species at the onset of drought, which however, it would be prudent to isolate animals in a drylot allows them to recuperate more rapidly when precipitation and avoid moving them directly from OWB-infested eventually returns to normal levels. pastures into un-infested areas for at least 7 days to allow passage of any possible viable seed. Stocking rates that do not account for areas occupied by OWBs may inadvertently overutilize native vegetation. Classical Biological Control Therefore, stocking may need to be adjusted to favor At present, no known organisms or pathogens (insects, native grasses. Continuous, intensive grazing should fungi, viruses, etc.) are present in the U.S. that are natural generally be used only on lands close to a full monoculture enemies or biocontrol agents for either OWB species. of O WBs; otherwise, native plants will probably be over- utilized. Chemical Control The primary herbicides used for OWB control are Intensive grazing of OWBs with cattle in the early part of glyphosate and imazapyr (Table 2). Both herbicides will the growing season may enhance grazing use. Fall gr azing provide bluestem control when properly applied; however, of OWBs using a deferred-rest, rotational grazing system the two herbicides are non-selective and will impact non- may also provide better utilization. However, additional target species. Therefore, precautionary measures should protein is required since protein and nutritional values for be taken if non-target plants (including woody species) OWBs decline significantly in the fall and winter. Protein need to be protected. Repeated use of the same herbicide supplements in granular, block, crystal, or liquid form can on OWB infestations could lead to herbicide resistance; be used in conjunction with grazing dead OWB plants. thus, the two herbicides should be alternated in their use. Protein supplements can increase palatability, % crude protein, and total digestible nutrients (TDN) in fall-winter Glyphosate will kill or control most other plants diets. Although these protein sources can b e fed in intermixed with OWBs, while imazapyr allows some containers , some forms of protein supplement may be placed native tallgrasses to survive and persist after application. directly on patches of standin g dead OWBs. Studies done in the Midwest have shown that Western wheatgrass (Pascopyrum smithii), tall dropseed Treatments that reduce standing dead material such as (Sporobolus compositus), sideoats grama, and western mowing or burning may encourage greater utilization of ragweed (Ambrosia psilostachya) had the best survival OWBs by grazing animals. A high stocking rate with grazing after glyphosate treatments; however, the herbicide is very animals may remove dead material, which will stimulate damaging to most mid and tall grasses. Big bluestem new O WB growth that can be treated by a foliar herbicide. ( gerardi), little bluestem (Schizachyrium Trampling by cattle can be used to break down clumps and scoparium), Indiangrass (Sorghastrum nutans), and mounds of OWBs if the cattle are concentrated within a sideoats grama were found in the Midwestern studies to be relatively small area. To concentrate animals, a temporary tolerant of some imazapyr treatments, and they may electric fence that is periodically moved to areas needing increase in density following OWB removal.

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Table 2. Herbicide recommendations

Common Broadcast Spot Chemical Product Treatment Treatment Time of 1 Remarks Name (active Example (rate per (spray Application 2 ingredient) acre) solution)

Glyphosate – Roundup, 2-3 lbs per 1.5% of a 5.5 lb Favorable growing Glyphosate is formulated as a product single Roundup acre per gallon conditions and with either 2 lb, 4 lb, or 5.5 lb active application Ultra, product adequate moisture ingredient per gallon. Certain brands Rodeo, should be present; require addition of a non-ionic surfactant or Accord apply when OWBs are (NIS). Read label carefully to mix the [others 2.0% of a 4 lb in boot stage or any proper rate of application. Do not add available] per gallon time prior to seed ammonium sulfate when spraying product production while rangelands. Also, consider tank mixes of leaves are green and both glyphosate and imazapyr for plant is actively increased control. See herbicide label for growing. details. Although immobile in soil, glyphosate Glyphosate – same as 1-2 lbs per same as above First application is at the is a non-selective amino acid inhibitor; split application above acre 5-leaf stage. Second its spray drift can damage non-target application is 8 weeks plants, including forbs and woody later. species.

Imazapyr – Habitat, 0.5 lbs per 1.0% of a 2 lb Favorable growing Herbicidal activity may be slow, and the single Arsenal acre per gallon conditions and adequate extent of control may not be evident until application [others product moisture should be the following growing season. available] present; apply when Imazapyr is a non-selective amino OWBs are in boot stage acid inhibitor. In addition to spray or any time prior to seed drift, non-target plants may also be production while leaves killed or injured by imazapyr are green and plant is through runoff, residue movement actively growing. in soil, or root exudates from treated plants. Imazapyr – same as 0.25 lbs per same as above First application is at the split application above acre 5-leaf stage. Second application is 8 weeks later.

1 Trade names for products are provided for example purposes only, and other products with the same active ingredient(s) may be available. Individual product labels should be examined for specific information and appropriate use with OWBs. 2 Spray solution is the herbicide/water ratio in a spray mix that may be used for spot treatment with backpack or hand-held sprayers. The amount of product applied during an annual growing season must not exceed the maximum application rate per acre as specified by the product label – refer to the product label for the site type and application.

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Aquatically approved herbicide formulations and then again at the same rate eight weeks later. Imazapyr surfactants of glyphosate and imazapyr must be used in may also be applied in a singl e dose at a rate of 0. 5 lb/ or near water. Each herbicide product has different acre when the plant is in the boot stage or later prior to requirements and restrictions. Therefore, label seed production, as long as the plant is green and instructions s hould be carefully followed when mixing favorable growing conditions exist. and applying any herbicide. For herbicide control of individual plants or small Herbicide Application patches with a handheld or backpack sprayer, apply a Applying herbicide to OWBs as a sgin le treatment 1.5% solution of a 5.5 lb glyphosate/gallon product or without follow-up can be ineffective or worse than not a 2.0% solution of a 4 lb glyphosate/gallon product. using herbicide at all. Following initial glyphosate Alternativel y, a 1.0% solution of a 2 lb imazapyr/gallon treatment, OWB seedlings can continue to emerge for product can be applied.

as long as 3 years. In many instances, OWBs have been Application Techniques observed to recover within 1 year after treatment (YAT) To limit impacts to desirable plants during herbicide or 2 YAT due to emergence of new seedlings from the applications, direct spray of OWBs from a backpack or soil seed bank and from basal buds of mature plants that hand-held sprayer is preferable to broadcast treatment. escaped herbicide treatment. Enough spray should be used to wet leaves but avoid OWB control on a short-term basis has been successful dripping from the plant. Adding a blue or red dye to the with both single and split applications of glyphosate solution will aid in identifying treated plants. A team of and imazapyr during the growing season. Whether applicators walking together side-by-side (about 10 feet applied as a single dose or as split applications, both apart) is an effective way to spray a defined area herbicides typically give similar OWB c ontrol. systematically . Th is method is particularly effectiv e for Mixtures of imazapyr and glyphosate can also provide treating relatively small, less dense infestations.

short-term control. Under dry conditions, greater rates A ropewick application method may provide modest of herbicide are required to achieve the same control as OWB control. Ro pewick applicator s can be hand-held lower rates of herbicide used during favorable growing or else towed or mounted on a tractor, ATV, or UTV . conditions, especially with g lyphosate. Ropewick application s do not control new or young For split applications of glyphosate using a broadcast seedlings, but they may control well-established plants treatment, apply 1-2 lb/acre at the 5-leaf stage and then with a taller canopy. If native species are mown or treat again at the same rate eight weeks later. With heavily grazed first, the ropewick can b e set lower and favorable growing conditions and adequate moisture, a mad e more effective. According to one Midwes t study, single dose of 2-3 lb/acre glyphosate may be broadcast a ropewic k applicatio n using glyphosat e and water in a applied as an alternative treatment when OWB plants 50:50 ratio on a volume to volume basis provided an are in the boot stage. Infestations can also be treated average of 65% control in the third season following with a single dose of gl yphosate at 2-3 lb/acre at any annual ropewick applications made in the first 2 years.

time late in the season prior to seed production if leaves For large infestations, it may be more practical to use a remain green and the plants are still growing or boomless or conventional boom sprayer tha t is photosynthesizing well. Single dose glyphosate mounted on a vehicle ( ATV, UTV, truck, or tractor) or applications in late season nhave f bee ound to be more else is towed. Any equipme nt (includ ing backpack effective as compared to early season applications. sprayers) used to spra y herbicide shoul d be calibrated . Alternatively, imazapyr can be broadcast applied in a See the Suggested Web Sites subsection at the end of split application at 0.25 lb/acre at the 5-leaf stage and this docum ent for c alibratio n information . Before

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spraying, always consider the need to reseed with desirable from becoming a more widespread and expensive problem native grasses after herbicide application. will necessita te stakeholders (agencies, landowners, etc.) working togethe r collaboratively, particularl y in manag ing Integrated Control Methods pathways (road systems, waterways , etc.) by which OWBs Grazing, mowing, or burning OWB infestations—applied can invade. A major emphasis should be to maintain or singly or in combination—do not adequately control OWBs. restore diversit y and resiliency of native plant The timing and frequency of these treatments may actually communities. increase OWB vigor relative to native plants and make Control and restoration e fforts for OWBs require long - OWBs even more competitive. However, use of these term planning, sustaine d management, and follow-up treatments either prior to herbicide application or between monitoring. To protec t pastures and native grasslands, split herbicide applications greatly increases herbicide eradication or at least containment s hould be employed effectiveness on OWBs, as the new green foliage arising against OWB i nfestations wherev er feasible. E fforts to from the treatment will potentially enhance total herbicide control OWBs in ROWs should especially be emph asized uptake and translocation. Herbicide label restrictions for and coordinated with State and county highway grazing should be followed. departments. Satellite populations and perimeter edges of

Tillage large infestations may be treated first with the entire

If OWBs are present in tillable areas such as previously infestation scheduled to be eradicated, contained, and/or at cropped areas, then plowing or deep disk tillage followed by least reduced in a series of steps over a period of several treatment of new OWB plants with glyphosate, imazapyr, or years. a mixture of the two can greatly reduce OWB cover. Follow- For lands where eradication or containment of OWBs are up treatments of emergent OWBs on the fallow land and no longer practicable due to widespr ead infestations, eventual reseeding with desirable vegetation are required to manageme nt efforts should focus on (1) slowing their keep OWBs from re-populating. Conducting tillage and spread if possible and (2 ) reducing OWB dominance in seeding of an annual crop such as winter wheat for 3 or more heavily in fested areas to increas e plan t and/or faunal consecutive years should also provide significant OWB diversity. However , it may be mor e cost -effective in some control. Reseeding to native grasses and forbs may then be situations to put control effort s toward protecting areas that possible if coupled with several years of herbicide remain free of OWBs rather than cau sing disturbance in treatments to control new OWB seedlings and plants that areas that are already extensively infested by them. escaped previous treatment. In most cases, at leas t 3 or more consecutive seasons of Managemen t Strategies field treatments will be necessary to eliminate or substantially reduce OWB infestations an d soil seedbanks In the Southwest, seeding of OWBs has historically been following initial treatment. Treated areas will require limited to ROWs, CRP lands, and drought-affected monitoring and likely retreatment to control newly rangelands. OWB species are not currently recognized as a emerging seedlings and recovering patches of O WBs. problem in Arizona or New Mexico as they are not yet Since it is useless to tr eat an area only one time without broadly established in pastures and native grasslands of retreatment, sufficien t resources must be allocated for the either State. However, OWB infestations are expected to area where control is attempted. After initial treatment, it continue expanding and eventually become a major threat is essential that resources are available to respray or retreat similar to the Midwest where OWBs have become highly the treated area as necessary. invasive across grassland areas. Success in keeping OWBs

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References and Further Greer, M.J., G.W.T. Wilson, K.R. Hickman, and S.M. Wilson. 2014. Experimental evidence that invasive Information grasses use allelopathic biochemical as a potential CABI. 2018. Bothriochloa ischaemum (yellow bluestem) mechanism for invasion: chemical warfare in [original text by G. Wilson, 2015]. In: Invasive nature. Plant and Soil 385:165-179. Species Compendium. Wallingford, UK: CAB Harmoney, K.R. 2010. Rate and timing of glyphosate International. www.cabi.org/isc. application to control Caucasian Old World Casey, J. 2014. Timing and intensity of steer use on Old bluestem (Bothriochloa bladhii). Invasive Plant World bluestem (Bothriochloa ischaemum) and Science and Management 3:310-314. blue grama (Bouteloua gracilis) in southern mixed Harmoney, K.R. 2016. Old world bluestem seedling grass prairie. Fort Hays State Univ., M.S. Thesis. emergence and vegetative cover following Clayton, M.K., J.L. Foster, K.C. McCuistion, T.W. glyphosate treatment. Kansas Agricultural Teinert, and M.M. Lesak. 2017. Introduced Experiment Station Research Reports: Vol. 2: Iss. bluestem grasses: management on native lands. 2. https://doi.org/10.4148/2378-5977.1182 Texas Agrilife Extension Service. ERM-036. Harmoney, K.R. 2016. Ropewick application to control Coleman, S.W., C.M. Taliaferro, and R.J. Tyrl. 2004. Old Old World bluestems. Kansas Agricultural World bluestems. p. 909-936. In L.E. Moser et al. Experiment Station Research Reports: Vol. 2: Iss. (ed.) Warm-season (C4) grasses. Agronomy 2. https://doi.org/10.4148/2378-5977.1183 Monographs 45. ASA, CSSA, and SSSA, Madison, Harmoney, K.R., and K.R. Hickman. 2012. Comparing WI. morphological development and nutritive value of Dee, J.R., S.M. Thomas, S.D. Thompson, and M.W. Caucasian Old World bluestem and native grasses. Palmer. 2016. Long-term late season mowing Online. Forage and Grazinglands doi:10.1094/FG- maintains diversity in southern US tallgrass prairie 2012-0127-01-RS. invaded by Bothriochloa ischaemum. Applied Harmoney, K.R., P.W. Stahlman, and K.R. Hickman. Vegetation Science 19: 442–453. 2004. Herbicide effects on established yellow Old Elmore, D., L. Goodman, K.R. Hickman, and K. Alspach. World bluestem (Bothriochloa ischaemum). Weed Options for Expiring Conservation Reserve Technology. 18:545-550. Program (CRP) Land (NREM-9016). Harmoney, K.R., P.W. Stahlman, and K.R. Hickman. Fulbright, T.E., K.R. Hickman, and D.G. Hewitt. 2013. 2007. Suppression of Caucasian Old World Exotic grass invasion and wildlife abundance and bluestem with split application of herbicides. Weed diversity, south-. Wildlife Technology 21:573-577. Society Bulletin 37(3):503–509. Hickman, K.R., G.H. Farley, R. Channell, and J.E. Steier. Gabbard, B.L., and N.L. Fowler. 2007. Wide ecological 2006. Effects of Old World Bluestem amplitude of a diversity-reducing invasive grass. (Bothriochloa ischaemum) on food availability and Biological Invasions 9:149–160. avian community composition within the mixed- George, A.D., T.J. O’Connell, K.R. Hickman and D.M. grass prairie. The Southwestern Naturalist 51:524- Leslie, Jr. 2013. Food availability in exotic 530. grasslands: a potential mechanism for depauperate Mittlehauser, J.R., P.W. Barnes, and T.G. Barnes. 2011. breeding assemblages. The Wilson Journal of Blackland prairie restoration in central Texas. Ornithology 125:526-533. Natural Areas Journal 31:226–233.

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Pate, F.M., and W.E. Kunkle. 1989. Molasses-based feeds Wilson, G.W.T., K.R. Hickman, M.M. Williamson. 2012. and their use as supplements for brood cows. Invasive warm-season grasses reduce mycorrhizal Circular No. S-365. Agric. Exp. Sta., Inst. root colonization and biomass production of native Food Agric. Sci., Gainesville. prairie grasses. Mycorrhiza 22:327-336.

Roberts, C. 2004. Caucasian Bluestem. University of Photo Image Libraries Extension Guide No. G4674. Online Photo images of OWBs may be found: at https://extension2.missouri.edu/g4674. Flora of . Available at Robertson, S. and K.R. Hickman. 2012. Aboveground http://floranorthamerica.org/ plant community and seed bank composition along an invasion gradient. Plant Ecology 213:1461- SEINet Plants Database. Available at 1475. http://swbiodiversity.org/seinet/

Robertson, S., K.R. Hickman, K.R. Harmoney, and D.M. Suggested Web Sites Leslie, Jr. 2013. Combining glyphosate with For information about calibrating spray equipment: burning or mowing improves control of yellow bluestem (Bothriochloa ischaemum). Rangeland KSU Research and Extension. Hand Sprayer Calibration Ecology & Management: 66:376-381. Steps Worksheet. Available at http://www.bae.ksu.edu/faculty/wolf/PDF/MF2915- Ruckman, E.M., S. Schwinning, and K.G. Lyons. 2012. Hand%20Sprayer.pdf Effects of phenology at burn time on post-fire recovery in an invasive C4 grass. Restoration NMSU Cooperative Extension Service Guide A- Ecology 20:756-763. 613, Sprayer Calibration. Available at http://aces.nmsu.edu/pubs/_a/A613.pdf Ruffner, M.E., and T.G. Barnes. 2012. Evaluation of herbicide and disking to control invasive bluestems in a south Texas coastal prairie. Rangeland Ecology & Management 65:277-285.

Schmidt, C.D. and K.R. Hickman. 2006. Stolon production in Caucasian Old world bluestem. Transactions of the Kansas Academy of Science. 109:74-76.

Schmidt, C.D., K.R. Hickman, R. Channell, W.J. Stark, and K.R. Harmoney. 2008. Competitive ability of native grasses and non-native (Old World Bluestems; Bothriochloa spp.) grasses. Plant Ecology 197:69-80.

Simmons, M.R., S. Windhager, P. Power, J. Lott, R.K. Lyons, and C. Schwope. 2007. Selective and non- selective control of invasive plants: effects of growing-season prescribed fire, herbicide, and mowing in two Texas prairies. Restoration Ecology 15:662–669.

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For more information or other field guides, contact: USDA Forest Service Southwestern Region Forest Health 333 Broadway Blvd., SE Albuquerque, NM 87102 Or visit the Southwestern Region’s website for invasive species: http://www.fs.usda.gov/goto/r3/invasivespecies

The use of trade or firm names in this publication is for reader information only and does not imply endorsement of any product or service by the U.S. Department of Agriculture. Recommendations made here for pesticide use are not obligatory, nor do they imply that discussed uses have been registered. All uses of pesticides must be registered by appropriate State and/or Federal agencies before they can be applied.

CAUTION: Pesticides can be injurious to , domestic animals, desirable plants, and fish or other wildlife—if they are not handled or applied properly. Use all pesticides carefully and lawfully. Follow recommended practices for the disposal of surplus pesticides and pesticide containers.