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Publication #ENH1256

Biology and Management of Mulberry Weed (Fatoua villosa) in Ornamental Crop Production1

Chris Marble and Shawn Steed2

Species Description

Class: Dicotyledonous plant

Family: Moraceae (mulberry family)

Other Common Names: Hairy crabweed, fatoua

Life Span: Summer annual

Habitat: Occurs in disturbed areas and wetlands; often found growing in landscapes, greenhouses, container pads, and in nursery pots. It prefers to grow in irrigated or moist shaded areas.

Distribution: Mulberry weed is native to Eastern Asia and was first reported in Louisiana in the 1950s (Bryson and DeFelice 2009). Mulberry weed has naturalized throughout much of the eastern United States and is found from Texas to Florida and north to Michigan and Delaware. It also occurs along the west coast from California into Washington (Gregory 2014; USDA NRCS 2014).

Growth Habit: Upright growth habit (Figure 1)

Figure 1. 

Mulberry weed (Fatoua villosa) growing inside a nursery container. Note upright growth habit.


Credit:

Annette Chandler, Mid-Florida Research and Education Center


[Click thumbnail to enlarge.]

Seedling: Seedlings are dark to light green. Cotyledons are round and notched at the center. First true leaves are simple and slightly serrate (toothed) and triangular in shape (Figure 2).

Figure 2. 

Mulberry weed seedlings.


Credit:

Annette Chandler, Mid-Florida Research and Education Center


[Click thumbnail to enlarge.]

Shoot: Stems are round, pubescent (hairy), and light green but can have a reddish to purple hue near the base. Shoot height can range from a few inches to over 4 feet. Leaves are simple, alternately arranged on the stem, papery in texture, pubescent, triangular to cordate (heart-shaped), and have serrate (toothed) margins (Figure 3).

Figure 3. 

Mulberry weed leaf.


Credit:

Annette Chandler, Mid-Florida Research and Education Center


[Click thumbnail to enlarge.]

Roots: Taproot

Inflorescence: Dense light green to purplish cymes (clusters) occur in leaf axils (Figures 4 and 5). Flower clusters begin turning dark brown as the plant ages.

Figure 4. 

Mulberry weed flowers. Note purplish hue of flowers and location in leaf axils.


Credit:

Annette Chandler, Mid-Florida Research and Education Center


[Click thumbnail to enlarge.]

Figure 5. 

Close-up view of flower in leaf axil.


Credit:

Annette Chandler, Mid-Florida Research and Education Center


[Click thumbnail to enlarge.]

Fruit and Seeds: Seeds (achenes) are light tan, oval, and about 1 mm in diameter (Wunderlin 1997). Some of the seeds are forcibly expelled when mature and can travel up to 4 feet away from the mother plant (Neal and Derr 2005).

Similar Species: When young, the mulberry tree (Morus alba) resembles mulberry weed. Mulberry tree also can be a problematic weed in nursery production and landscapes but grows much taller (up to 45 feet tall) and exudes a milky sap from young twigs when broken (Neal and Derr 2005). Another group of similar looking species is galinsoga (Galinsoga spp.) which can be distinguished from mulberry weed by its white ray and yellow disc flowers.

Plant Biology

Mulberry weed occurs from spring to fall in Florida, primarily growing in moist, shaded areas. Plants flower from early spring through late fall and then die after the first freeze. Optimal temperatures for germination are approximately 70 to 85°F, but seeds have been shown to germinate in temperatures ranging from 60 to 100°F (Penny and Neal 2003). Seedlings may flower and fruit within 12 days of reaching the two-leaf growth stage (Neal and Derr 2005). Germination may be reduced in dry conditions; however, this is rarely seen since irrigation typically is applied regularly to nursery crops and landscapes.

Management

Physical and Cultural Control

Mulberry weed prefers moist soil conditions, but reducing irrigation is often impractical in a container nursery setting. Due to the fast growth and prolific seed production, control efforts should focus on prevention and sanitation. Regularly scout container beds, greenhouses, propagation areas, and non-crop areas for presence of this weed. Closely inspect new plant shipments for presence of weeds. Hand pull mulberry weed as quickly as possible before it flowers. Remove pulled weeds from production areas or landscape beds and dispose of them, as seed can continue to be spread from pulled weed material if left on the soil. Mulberry weed germination is stimulated by light, therefore mulch materials placed on top of container media or in the landscape can significantly reduce seed germination. Pine bark nuggets applied at depths of 1.5 inches or more have been shown to provide up to 90 percent control (Penny and Neal 2003).

Chemical Control

Preemergence

Mulberry weed is effectively controlled with many preemergence herbicides but continues to be a problematic weed due to fast growth and prolific seed production. A list of preemergence herbicides labeled for use in and around ornamentals in nurseries and landscapes which can be used for mulberry weed control is provided in Table 1.

Postemergence

Many different postemergence herbicides will control mulberry weed, although these herbicides can be applied as only a directed application. Contact herbicides such as diquat (Reward®), and pelargonic acid (Scythe®) and systemic herbicides such as glyphosate (RoundUp®) will control mulberry weed, but these products are most effective when weeds are less than 4 inches tall and actively growing. When applying these herbicides, ensure that the herbicide spray does not drift or come in contact with any part of the ornamental plants.

References

Bryson, C. T. and M. S. DeFelice (eds). 2009. Weeds of the South. Athens, GA: University of Georgia Press.

Gregory, N. F. 2014. Mulberry weed (Fatoua villosa). University of Delaware Cooperative Extension Factsheet. https://extension.udel.edu/factsheet/mulberry-weed-fatoua-villosa/.

Neal, J. C. and J. F. Derr. 2005. Weeds of container nurseries in the United States. Raleigh, NC: North Carolina Assoc. of Nurserymen, Inc.

Penny, G. M. and J. C. Neal. 2003. “Light, temperature, seed burial, and mulch effects on mulberry weed (Fatoua villosa) seed germination.” Weed Tech 17:213–218.

USDA National Resources Conservation Service. 2014. The PLANTS database. http://plants.usda.gov.

Wunderlin, R. P. 1997. “Moraceae.” In Flora of North America Editorial Committee, eds., Flora of North America North of Mexico. Vol. 3. New York: Oxford University Press. pp. 388–392.

Tables

Table 1. 

Partial list of preemergence herbicides labeled for use in ornamental plant production and landscapes to control mulberry weed.

Common Name (active ingredient)

Example trade name and formulation

WSSA Herbicide Group1

Efficacy2

Container production

Field production

Greenhouse or fully enclosed structures

Landscape

dithiopyr

Dimension® 2EW

3

S-C

YES

YES

NO

YES

pendimethalin

Pendulum® 2G

3

S

YES

YES

NO

YES

Pendulum® 3.3EC, 3.8AC

YES

YES

NO

YES

prodiamine

Barricade® 4FL, 65 WG

3

S

YES

YES

NO

YES

flumioxazin

Broadstar™ 0.25G

14

C

YES

YES

NO

YES

SureGuard® 51WDG

YES3

YES3

NO

YES4

oxadiazon

Ronstar® 2G

14

S-C

YES

YES

NO

YES

dimethenamid-p

Tower® 6EC

15

S-C

YES

YES

NO

YES

s-metolachlor

Pennant Magnum® 7.6 EC

15

S

YES

YES

NO

YES

isoxaben

Gallery® 75DF, 4.16SC

21

S-C

YES

YES

NO

YES

indaziflam

Marengo® 0.622 SC

29

C

NO5

YES

YES6

NO

Marengo® 0.0224G

YES

YES

NO

NO

benefin + oryzalin

XL 2G

3 + 3

S-C

YES

YES

NO

YES

pendimethalin + dimethenamid-p

FreeHand® 1.75G

3 + 15

C

YES

YES

NO

YES

trifluralin + isoxaben

Snapshot® 2.5TG

3 + 21

S-C

YES

YES

NO

YES

prodiamine + isoxaben

Gemini™ 3.7SC

3 + 21

S-C

YES

YES

NO

NO

oxadiazon + pendimethalin

Jewel® 3.25G

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + oryzalin

Rout® 3G

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + pendimethalin

OH2® 3G

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + prodiamine

Biathlon® 2.75G

14 + 3

S-C

YES

YES

NO

YES

oxyfluofen + trifluralin

Granular Herbicide 75 5G

14 + 3

S-C

YES

YES

NO

YES

oxyfluorfen + oxadiazon

Two OX E-Pro 3G

14 + 14

S-C

YES

YES

NO

YES

trifluralin + isoxaben + oxyfluorfen

Showcase® 2.5G

3 + 21 + 14

C

YES

YES

NO

YES

1Herbicide groups are based according to primary sites of action and can be used to select herbicides that have differing sites of action (Weed Technology 17:605–619 [2003]) so as to minimize the potential for the development of herbicide resistant weeds.

2P = poor control; S = suppression, C = good control. Efficacy may vary (better or worse) depending on environmental factors and weed pressure in a given location.

3Can be used only in selected conifer and deciduous tree species. Check manufacturer's label for a complete list of species and recommended application methods.

4Can be applied as a directed application around established woody landscape ornamentals.

5Marengo 0.622 SC can be used in pot-in-pot container ornamentals as a directed application only. Specticle™ is labeled for use in landscapes.

6Labeled for use on greenhouse floors prior to plant production. Plants can be placed back inside greenhouse 24 hours after application.

Footnotes

1.

This document is ENH1256, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date April 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Chris Marble, assistant professor, Mid-Florida REC, Apopka, Florida; Shawn Steed, environmental horticulture production Extension agent, Seffner, FL; UF/IFAS Extension.

Mention of a commercial or herbicide brand name or chemical does not constitute a recommendation or warranty of the product by the authors or the University of Florida, Institute of Food and Agricultural Sciences, nor does it imply its approval to the exclusion of other products that may also be suitable. Products should be used according to label instructions and safety equipment required on the label and by federal or state law should be employed. Pesticide registrations may change, so it is the responsibility of the user to ascertain if a pesticide is registered by the appropriate state and federal agencies for its intended use.


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