December 16, 2020

The Weeds on Your Farm

Introduction

Profitable crop production depends on effective weed control. Weeds can reduce crop yield potential by competing for water, nutrients, and light. Some weeds release toxins that inhibit crop growth, and others may harbor insects, diseases, or nematodes that attack crops. Weeds can also reduce harvest efficiency and produce seed that can impact future crops.

Not all weeds compete with crops equally (Table 1).¹ Broadleaf weeds tend to be more competitive than grasses in corn. For example, the predicted weed densities per 40 feet of row required to cause a 10% yield loss in corn would be 80 foxtails compared to 40 pigweeds and only 10 cockleburs. Canopy closure of the crop can limit the competitive ability of weeds. However, broadleaf weeds are better able to avoid the shading effects of the canopy and compete longer into the growing season. Early-germinating weeds are generally more competitive than weeds that emerge later in the growing season. Fields that experience moisture stress are also at greater risk of yield losses from weed competition. Heavier soils that hold moisture better can tolerate higher populations of weeds that may impact crop yield potential.

Late-emerging weeds can include those that emerge after control tactics have been implemented. The impact of late-emerging weeds decreases rapidly if weeds emerge 3 weeks or more after crop emergence. The competitiveness of late-emerging weeds is strongly influenced by how quickly the crop canopy develops. Stress factors that reduce crop growth can increase the impact of late-emerging weeds. These weeds are at a competitive disadvantage to the crop due to their delayed emergence but are still capable of causing economic losses.

Late-emerging weeds should not be ignored because they are capable of producing significant quantities of seed. If weeds have not initiated seed set at the time of herbicide application, seed production should be eliminated or reduced. However, if the fruiting structures are visible, it is unlikely that the application will reduce weed seed production or viability of the seeds. The other benefit of late-season weed control is harvest efficiency, and there are situations where these applications may be worthwhile.

Effective weed control in field crops requires the use of multiple management techniques including cultural methods as well as herbicides. Growing the same crop year after year and utilizing the same weed control techniques encourages the development of problem weeds and potentially, herbicide resistance. Utilizing crop rotation, tillage, and a diversified herbicide portfolio helps reduce this problem.

Identifying weeds properly is an essential first step in a weed management plan. This guide provides photos and identifying characteristics of grass and broadleaf weeds common to the crop’s growing region.

Click below on Grasses, Sedges or Broadleaves to identify and learn about the weeds on your farm.

Overview

Properly identifying grass weed species during their early growth stages can lead to a more effective management plan. Given that grass weed management is most effective when weeds are small, a hand or pocket lens with 10X magnification can improve grass weed identification.

The ligule and collar region of the plant is where the main characteristics used for grass identification are located (Figure 1). Grass leaves are either rolled or flat within the stem. Sedges can be identified by a triangular stem. Ligules of grasses will either be absent, hairy, or membranous (Figure 2). Auricles will either be present or absent. Below are descriptions and pictures to aid in identifying some of the common grass species found in agronomic crops in the corn growing region as well as management of these species.

Figure 1. Grass identification characteristics.

Figure 2. Grass ligule types.

Winter Annual Grasses

Summer Annual Grasses

Perennial Grasses

Sedges

Common name: Yellow nutsedge

Scientific Name: Cyperus esculentus

Life Cycle: Perennial

Figure 34. Yellow nutsedge seedling.

Figure 35. Yellow nutsedge rhizomes and nutlets. Picture courtesy of Steve Dewey, Utah State University, Bugwood.org.

Figure 36. Yellow nutsedge flower heads. Picture courtesy of Howard F. Schwartz, Colorado State University, Bugwood.org

Identification: Yellow nutsedge, a problem perennial weed in field crops throughout the U.S., is a member of the sedge family but often mistaken for a grass because of its narrow grass-like leaves. However, it is easily distinguished from grasses by its triangular stem, which is free from nodes. The leaves are shiny, yellow-green, and hairless in groups of three at the base of the plant (Figure 34). Yellow nutsedge reproduces by small, underground tubers, called nutlets, that form at the end of rhizomes (Figure 35).It can also spread by rhizomes. Yellow nutsedge produces a seed head as a cluster of yellow-brown spikes at the tip of its stem; however, seeds rarely germinate (Figure 36).

Management: Yellow nutsedge is troublesome; however, competitive crops like corn and soybean can usually outgrow and shade yellow nutsedge except in the case of a severe infestation. An integrated program combining growth suppression from tillage, cultivation, and herbicides followed by shading from competitive crops can be effective in managing yellow nutsedge. Soil clumps containing tubers and rhizomes can be spread by tillage and harvest equipment, so these should be cleaned before moving to an uninfested field. Many herbicides are available for sedge control, but proper application timing is critical to optimize control.

Sources:

Yellow nutsedge. Department of Plant, Soil, and Microbial Sciences. Weeds. Michigan State University. http://www.canr.msu.edu/weeds.

Winter Annual/Biennial Broadleaf Weeds

Overview

Winter annual weeds can become a major problem in crop production when not controlled in the fall or early spring, especially in no-till systems. Winter annual weeds typically emerge from late summer through fall, can overwinter, and then flower to set seed in the spring/early summer. Seedling winter annual weeds can be difficult to distinguish from other weeds, particularly if they are in the same family (Table 2). Many fall-emerging broadleaf weeds have a rosette growth stage such as dandelion, horseweed, prickly lettuce, shepherd’s purse, and other members of the Brassicaceae, making identification more difficult.

The impact of winter annual weeds in cropping systems is sometimes overlooked because these weeds typically complete most of their life cycle prior to or shortly after corn and soybean planting. Dense mats of winter annual weeds may delay soil warming in spring, compete for water and nutrients, and interfere with crop planting. Winter annual weed species are hosts for some pests (Table 3). Henbit and purple deadnettle are hosts for soybean cyst nematode.

Proper identification can help focus weed management decision making. Selecting the right herbicides and proper application timing can influence performance. Common winter annual broadleaf weeds in the Midwest include: marestail, henbit, purple deadnettle, shepherd’s purse, field pennycress, prickly lettuce, and chickweed.
Common chickweed

Common name:  Common chickweed

Scientific name: Stellaria media

Life Cycle: Winter annual

Figure 37. Common chickweed plant. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.

Figure 38. Common chickweed flower.

Figure 39. Common chickweed seeds. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org

Identification: Common chickweed is a winter annual that can have several generations per year during cool, wet seasons, and forms prostrate, dense mats. Common chickweed leaves are opposite, light green, rounded to egg-shaped, with pointed tips, smooth margins, and hairless or with a few hairs near the base (Figure 37). Common chickweed has a single straight row of hairs along the stem. Lower stems often root at the nodes.

Small, white flowers are borne in clusters at the end of stems. Flowers have 5 deeply-notched petals, resembling a pair of petals, and though small, are quite noticeable (Figure 38). Fruit are slightly curved, an oval capsule that contains many tiny, brown seeds (Figure 39).

Management: Heavy infestations of common chickweed are competitive with crops, especially in small grains. Tall wheat cultivars and denser plant populations can help suppress chickweed. Tilling in the fall prior to wheat planting can help give wheat a head start. Common chickweed should be controlled prior to planting in no-till systems. A fall herbicide application can effectively reduce weed populations from overwintering and help reduce the number of seeds set in the spring. In addition, chickweed can serve as an alternate host for a range of crop pests including wireworm, black cutworm, and soybean cyst nematode and should be managed.

Similar species: Common chickweed is similar in growth habit and appearance to mouseear chickweed (Cerastum fontanum ssp. vulgare). Mouseear chickweed differs by having a perennial habit with densely hairy, oblongleaves lacking petioles, and dark-green foliage (Figure 40).

Figure 40. Mouseear chickweed is similar to common chickweed but has densely hairy leaves and a perennial growth habit. Photo courtesy of Theodore Webster, Ohio State Weed Lab, The Ohio State University, Bugwood.org.

Field pennycress

Common name: Field pennycress

Scientific name: Thlaspi arvense

Life cycle: Winter or summer annual

igure 41. Field pennycress rosette leaves. Picture courtesy of Steve Dewey, Utah State University, Bugwood.org.

Figure 42. Field pennycress flowers and stalk. Photo courtesy of Steve Dewey, Utah State University, Bugwood.org.

Figure 43. Field pennycress seed capsules. Photo courtesy of Steve Dewey, Utah State University, Bugwood.org

Identification: Field pennycress is a member of the mustard family and has either a winter or summer annual growth habit. It can be found in nearly every state, even as far north as Alaska. Seedlings develop into a compact basal rosette with a slender taproot system (Figure 41). Lower leaves are oval to spatula-shaped with wavy margins, rounded tips, and distinct petioles. Upper leaves are alternate with toothed to smooth margins and clasping bases. Basal leaves fall off before maturity.

Stems bolt from the basal rosette to flower (Figure 42). Flowers are terminal clusters with 4 small, white petals. Each flower produces a single seedpod that is bright green, flat, and round to oval in shape with distinct membranous wings that have a notch at the end. (Figure 43). The entire plant turns bright yellow to tan at maturity. All plant parts have a sharp odor and can give a bitter taste to milk if eaten by cows.

Management: Field pennycress can be controlled easily with tillage or burndown herbicide applications. Herbicides work best when plants are in the rosette stage and growth is active, before seeds start to shed.

Sources:

Anderson, B., Bradley, K., and Perez-Hernandez, O. April 19, 2016. Weed of the month: field pennycress. Integrated Pest Management. University of Missouri. https//ipm.missouri.edu.

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Henbit /purple deadnettle

Common name: Henbit

Scientific name: Lamium amplexicaule

Life Cycle: Winter annual

Figure 44. Henbit seedling. Photo courtesy of Steve Dewey, Utah State University, Bugwood.org.

Figure 45. Mature henbit plants.

Figure 46. Henbit flowers.

Identification: Henbit is a member of the mint family and has square stems. Leaves are opposite, circular to heart-shaped, with a crinkled leaf surface, hairy, and have rounded teeth along the leaf margins (Figure 44). Lower leaves are attached to the stem by long petioles, upper leaves lack petioles and encircle the stem. Flowers are pink to purple in a two-lipped tube form in whorls in upper leaf axils (Figure 45). Henbit is more prevalent in no-till fields and thick patches can make areas appear purplish as plants flower (Figure 46).

Figure 47. Purple deadnettle (left) compared with henbit (right)

Similar Species: Henbit can be confused with ground ivy (Glechoma hederacea) and purple deadnettle (Lamium purpureum). However, purple deadnettle differs by having more triangular-shaped leaves, upper leaves with petioles, and red to purple leaf coloration (Figure 47). Ground ivy differs in that it is a creeping perennial with square stems that root at the nodes.

Management: Henbit and purple deadnettle both emerge mostly in the fall with flowering and seed set in the spring and are primarily weeds of no-till systems. Both are easily controlled with herbicides. Fall and early spring herbicide applications are most effective and may also suppress seed production. There is also some spring emergence, so consider herbicide options with some residual control.

Marestail (horseweed)

Common name: Marestail (horseweed)

Scientific name: Conyza canadensis

Life Cycle: Winter annual

Figure 48. Marestail seedlings. Picture courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.

Figure 49. Erect central stem of horseweed.

Figure 50. Marestail panicle flower head. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.

Figure 51. Marestail seed with pappus that aids in wind-dissemination. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.

Identification: Marestail, also known as horseweed, emerges in both fall and spring. Seedlings develop into a basal rosette (Figure 48). Fall-emerged plants survive the winter as a basal rosette and bolt in the spring. Marestail leaves are alternate, linear, and simple with entirely or slightly toothed margins (Figure 49). Leaves get progressively smaller toward the top of the plant. When plants are mature, leaves do not have petioles. The main stem bolts, giving the plant the appearance of a horse’s tail. Flowers are arranged in a panicle with numerous white ray flowers (Figure 50). Fruit are small, yellow achenes, each with a white pappus that aids in wind dispersion (Figure 51). Marestail seeds usually germinate in the fall or spring but can germinate midsummer when growing conditions are adequate. Plants can reach up to 6 feet in height. Once plants are over 5 inches tall, they are difficult to control with herbicides alone.

Watchouts: Marestail has increased in prevalence and herbicide-resistant biotypes have developed due to three primary factors: use of reduced or no-tillage, a lack of diversity in crop rotations (production of soybeans in the same field for consecutive years), and limited herbicide diversity. Herbicide-resistant marestail biotypes have been identified in several states for ALS inhibitor, triazine, paraquat, and glyphosate herbicides. Abundant seed production and wind dispersal facilitate the spread of herbicide-resistant marestail biotypes.

Management: Several factors can influence marestail control. The size and stage of growth at the time of herbicide application can have a significant effect on efficacy. Marestail is most susceptible to control when it is small, in the rosette stage of growth, and less than 4 to 6 inches tall. Once marestail bolts it is more difficult to control. The second factor is the extended emergence time of marestail, which can complicate the timing of burndown applications. In many cases, including a herbicide with residual activity can help control later-emerging plants. A third challenging factor to marestail control is the limited number of postemergence herbicide options, particularly in soybean. Because of this limitation it is important to use burndown, preplant, and preemergence herbicides effectively.

There are herbicide options available for fall or spring burndown, preemergence, and postemergence applications for marestail control. Preemergence herbicides with residual activity should be the foundation of a marestail management program. Marestail susceptibility to herbicides declines substantially once the plant bolts in the spring.

 Marestail management tips:

Fall or early spring herbicide application for emerged plants to reduce heavy populations or seedlings. Plan for an additional herbicide application closer to planting.
Spring burndown application to marestail less than 4 inches tall to prepare a clean seed bed.  
Add residual herbicides to the spring burndown application.
Use full label rates of herbicides for maximum residual activity and postemergence activity on variable-height marestail.
Herbicide applications with multiple sites of action should be used in areas with ALS-, glyphosate-, or multiple herbicide-resistant biotypes.¹
Use postemergence herbicides in-crop to control escaped plants.
Rotate crops and till to reduce heavy marestail infestations.¹
Consult product labels for use precautions and restrictions to prevent crop injury or carryover.

 

Sources:

¹Loux, M., Stachler, J., Johnson, B., Nice, G., Davis, V., and Norby, D. 2006. Biology and management of horseweed. GWC-9. https://www.extension.purdue.edu

Lingenfelter, O., Klodd, A., and Curran, N. November 13, 2017. Marestail (horseweed) management. Penn State Extension. http://extension.psu.edu.

Sprague, C. November 2018. Herbicide-resistant horseweed (marestail) in Michigan: keys to management in no-till soybean. Michigan State University Weed Science. http://www.msuweeds.com

Prickly lettuce

Common name: Prickly lettuce

Scientific name: Latuca serriola

Life Cycle: Winter annual or biennial

Figure 52. Prickly lettuce seedlings. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org. bugwood

Figure 53. Prickly lettuce rosette. Photo courtesy of Ohio State Weed Lab, The Ohio State University, Bugwood.org. AEM

Figure 54. Prickly lettuce leaves exhibiting characteristic spines on midveins of lower leaf surface. Photo courtesy of Steve Dewey, Utah State University, Bugwood.org. bugwood

Figure 55. Prickly lettuce seed include a feathery pappus attached to a long stalk. Photo courtesy of Steve Dewey, Utah State University, Bugwood.org. bugwood

Identification: Prickly lettuce, also known as wild lettuce, is a common winter annual or biennial that can grow up to 6 feet tall. Seedlings develop as a rosette and stem elongate later (Figure52). The leaves are alternate, clasp the stem, are deeply lobed with spiny margins (Figure 53). The leaves have a row of spines along the mid-vein of the lower surface which is a distinguishing characteristic of this plant (Figure 54). Leaves become smaller and more lanceolate toward the top of the stem and may lack spines. The stems are hollow, and the stem and leaves will exude a milky sap.

Prickly lettuce produces yellow flower heads with up to 25 flowers resembling dandelion flowers. Prickly lettuce seeds travel on wind currents with the help of their downy, white plumes (Figure 55).

Management: Seedlings and rosettes of prickly lettuce are easily controlled by cultivation. There are several herbicide options available for fall or spring burndown, preemergence, and postemergence applications for prickly lettuce control. Plants become more difficult to control with herbicides once the flowering stems have begun to elongate.

Sources:

Montgomery, G., Bond, J., and Eubank, T. November 28, 2012. Weed of the week: prickly lettuce. Mississippi Crop Situation. Mississippi State University Extension. http://www.mississippi-crops.com

Shepherd’s purse

Common name: Shepherd’s purse

Scientific name: Capsella bursa-pastoris

Life Cycle: Winter or summer annual

Figure 56. Shepherd’s purse basal rosette. Photo courtesy of Steven Gower.

Figure 57. Shepherd’s purse flower and seed head. Photo courtesy of Steven Gower.

Figure 58. Shepherd’s purse seeds. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.

Identification: Shepherd’s purse is a member of the mustard family. Dandelion-like leaves initially develop from a basal rosette (Figure 56). Small stem leaves are alternate with smooth or toothed margins and clasping bases. Stems, up to 2 feet tall, bolt from the basal rosette to flower. White flowers with 4 small petals are found in a terminal cluster. The seed pods are very distinct heart-shaped to triangular pods found on elongated, unbranched stems (Figure 57). Seeds are oblong, grooved and yellowish red to brown (Figure 58). Each plant can produce thousands of long-lived seeds.

Similar species: In the basal rosette stage, shepherd’s purse can be confused with dandelion. Once it starts producing pods in the spring there is very little mistaking of identity.  The arrow-shaped pod is very distinctive.

Management: Although shepherd’s purse is fairly common, it is easy to control in the fall.  The use of glyphosate or 2,4-D in the fall when shepherd’s purse is in the rosette stage will typically control it.  Shepherd’s purse bolts, flowers, and starts to set seed early in the spring, often too early to get into the field.  Once it starts to set seed control can be more inconsistent. 

Wild carrot

Common name: Wild carrot

Scientific name:  Daucus carota

Life Cycle:  Biennial

Figure 59. Wild carrot seedlings. Photo courtesy of Steven Gower.

Figure 60. Young wild carrot leaves. Photo courtesy of Ansel Oommen, Bugwood.org

Figure 61. Wild carrot flower cluster. Photo courtesy of Rob Routledge, Sault College, Bugwood.org

Figure 62. Wild carrot seeds. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org

Identification: Wild carrot, also known as Queen Anne’s lace, is a biennial plant in the parsley family. It germinates and emerges in spring, developing a rosette of delicate, deeply-lobed, feathery or fern-like leaves (Figures 59 and 60). The foliage is very similar to garden carrots and will smell similar when crushed. Some plants will flower and set seed during the first year of growth, but most will overwinter without flowering. When winter comes, these first-year leaves will die back, but the strong taproot overwinters. The second year, plants send up a tall flower stalk and more leaves.

The flower, called an umbel, is a flat-topped cluster of small, white flowers, 2 to 5 inches across (Figure 61). Each plant can have several flowers. The flower heads face upward during the day and bend down at night. After fertilization, the flower head folds up and has a “birds nest” appearance. Fruit have two egg-shaped sections; each section is yellow to grayish brown, flattened on one side, and ridged with barbed prickles to aid in dispersal (Figure 62). Healthy wild carrot plants can produce as many as 1,000 to 40,000 seeds per plant, and seeds can live and germinate over a 7-year period or longer.

Management: Wild carrot disseminates only by seed so any time plants are prevented from going to seed future infestations are reduced. Tillage will control wild carrot. Spring applications of labeled herbicides are effective in controlling wild carrot seedlings in other crops. However, once wild carrot becomes established, fall herbicide applications are more effective.

Wild mustard

Common name: Wild mustard

Scientific name: Sinapis arvensis

Life Cycle: Winter or summer annual

Figure 63. Wild mustard rosette. Photo courtesy of Steven Gower.

Figure 64. Wild mustard plant with flowering shoots.

Figure 65. Wild mustard fruit. Photo courtesy of L.L. Berry, Bugwood.org.

Identification: Wild mustard is a winter or summer annual and is considered a noxious weed in several states. The lower leaves of wild mustard occur as a basal rosette, petiolated, and are unevenly-lobed with coarsely-toothed margins (Figure 63). Upper leaves are alternate, petioles are absent or short, with coarsely-toothed margins, pointed tips, and gradually become smaller towards the top.

Erect stems bolt from the basal rosette to flower with white hairs that point downward and purple rings at the base of young stems. Bright-yellow flowers with 4 petals are found in terminal clusters (Figure 64). Fruit are cylinder-shaped capsules about an inch long with a beak at the tip (Figure 65).

Management: In a no-till system, timing herbicide applications before bolting is the key to successful control. Some populations (North Dakota) of wild mustard have developed resistance to Group 2 (ALS inhibitor) herbicides.

Diseases and Insect Pests Harbored: Wild mustard is more prevalent in no-till systems and can also serve as an alternate host to soybean cyst nematode and many insect pests.

Sources:

Cahoon, C. 2016. Wild mustard and wild radish. Virginia Tech Extension. http://blogs.ext.vt.edu

Yellow rocket

Common name: Yellow rocket

Scientific name: Barbarea vulgaris

Life Cycle: Winter or summer annual

Figure 66. Yellow rocket lower leaf. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org]

Figure 67. Yellow rocket basal rosette. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.

Figure 68. Yellow rocket mature plant. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.

Figure 69. Yellow rocket flowers and capsules. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org

Identification: Yellow rocket can be a winter annual or biennial and reproduces by seed. Yellow rocket is most commonly found in no-till fields and contributes to the blanket of yellow covering in fields in the spring.

Yellow rocket is a member of the mustard family and has leaves with several smaller lobes and one large terminal lobe (Figure 66). Seedlings have round to egg shaped cotyledons on long stalks with smooth, shiny, dark green leaves that initially develop from a basal rosette (Figure 67). Leaf stems are arranged alternately and become progressively shorter toward the tip of the plant. Flowering stems are produced during the second year and can reach up to 3 feet in height (Figure 68). Bright-yellow flowers with 4 petals are found in terminal clusters. Fruit are slender, slightly curved, approximately 1-inch long capsules, with a beak at the tip and are almost square in cross-section (Figure 69).

Similar Species: At maturity, the flowers of several mustard species, including wild mustard and wild radish, will resemble those of yellow rocket. However, wild radish has leaves that are covered with stiff hairs unlike wild mustard or yellow rocket. Additionally, the large terminal lobe in the leaves of yellow rocket helps to distinguish this weed from wild mustard.

Management: Herbicides are highly effective at controlling younger, smaller weeds. The use of an effective early burndown to manage winter annual weeds like the mustard species is an important first step for a clean field for crop planting. Including a product with residual activity helps reduce early-season weed competition and helps manage winter annuals that can serve as alternate hosts for insects and soybean cyst nematode.

Summer Annual Broadleaf Weeds

Perennials

General Weed Management Considerations

It is important to start the season clean with tillage or a burndown herbicide application. Allowing weeds to be present at planting because of skipping or delaying the burndown application will give weeds a competitive advantage with the crop.
The use of preemergence herbicides at planting can reduce the risk of early-season competition by reducing densities of weeds that can emerge with the crop.
The use of strictly postemergence herbicide application programs can by risky. Weeds grow rapidly, and weather can delay postemergence applications which can result in loss of yield potential. Surveys have shown that where weeds are managed with only postemergence herbicides, application timings often occur too late to protect the full yield potential of corn from early weed competition.²

The use of preemergence and postemergence herbicides in sequential applications or in tank mixtures can be the best approach to weed control. Weeds should be controlled throughout the season to protect yield potential, using a mix of herbicides and multiple sites of action that can help to prevent the development and spread of resistant weeds.

Sources:

¹VanGessel, M. Weed management in row crops: application to corn production - competitive index factor chart. Northeast IPM Module number 10. http://northeastipm.org.

²Fickett, N.D., Boerboom, C.M., and Stoltenberg, D.E. 2013. Predicted corn yield loss due to weed competition prior to postemergence herbicide application on Wisconsin farms. Weed Technology 27:54-62.

Schaefer, K., Mueller, D., Sisson, A., Hartzler, B., Anderson, M., Jha, P., and McGrath, C. 2019. Weed identification. Field Guide. 2nd Edition. Iowa State University Extension and Outreach.

Everman, W., Sprague, C., Gower, S., and Richardson, R. 2014. An IPM Pocket Guide for Weed Identification in Field Crops. Bulletin E-3081. Michigan State University Extension.

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The Weeds on Your Farm

Introduction

Click below on Grasses, Sedges or Broadleaves to identify and learn about the weeds on your farm.

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General Weed Management Considerations

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